infectious diseases branch division of …sandiegohealth.org/disease/dhs/vbd_ca_annual_2008.pdf ·...

INFECTIOUS DISEASES BRANCH

DIVISION OF COMMUNICABLE DISEASE CONTROL

CENTER FOR INFECTIOUS DISEASES

CALIFORNIA DEPARTMENT OF PUBLIC HEALTH

Arnold Schwarzenegger Governor

State of California

Kimberly Belshé, SecretaryHealth and Human Services Agency

Mark B Horton, MD, MSPH, DirectorDepartment of Public Health

2008

ANNUAL REPORT

VECTOR-BORNE DISEASE SECTION

iState of CaliforniaCalifornia Department of Public Health

June 2009

Vector-Borne Diseases in California, 2008

I am pleased to present to you the 2008 Annual Report for the Vector-Borne Disease Section (VBDS) of the California Department of Public Health (CDPH). VBDS staff conducted surveillance, prevention, and control of existing and emerging vector-borne diseases throughout California in 2008.

West Nile virus (WNV) activity was widespread in 2008 with 445 cases reported from 27 counties. The epicenter of activity was in southern California where an increase in neglected swimming pools, due in part to the high home foreclosure rate, spurred extensive backyard mosquito breeding. VBDS worked with local vector control agencies to address mosquito problems and, in particular, published a document that outlined best management practices for mosquito control on California state properties. VBDS continued to successfully coordinate the WNV surveillance program and early in 2008 we assumed responsibility for testing sentinel chicken sera in our laboratory.

In 2008 VBDS staff investigated several emerging pathogens. In Lake County, we worked with local officials and the U.S. Centers for Disease Control and Prevention (CDC) to investigate the first documented human infection with Rickettsia 364D. In the Sierra Nevada foothills, VBDS collaborated with local officials and the CDPH Microbial Diseases Laboratory to identify only the second human case of infection with Bartonella washoensis; we implicated ground squirrel fleas from the property as the likely disease vector. VBDS partnered with social service organizations to provide education on prevention and control of louse-borne diseases among homeless persons in San Francisco, San Jose, and Los Angeles. Head and body lice collected from homeless persons were found to be infected with Bartonella quintana through testing done in collaboration with CDC.

Under a pilot agreement with the National Park Service (NPS), VBDS conducted vector-borne disease surveillance in several NPS units, such as Alcatraz Island and Manzanar National Historic Site, where risk of exposure to vector-borne pathogens had not been previously assessed. Indicators of hantavirus and plague risk were consistently low in surveillance data from NPS units, US Forest Service lands, and elsewhere, perhaps due to lower rodent numbers in 2008 than in previous years.

Many of you are our collaborators and colleagues and I hope that you find the information contained in this annual report to be of value as we collectively strive to promote and protect the health of all Californians.

Respectfully,

Vicki L. Kramer, Ph.D., ChiefVector-Borne Disease Section

Foreword

iiState of CaliforniaCalifornia Department of Public Health


June 2009

Foreword ................................................................................................................ i

Vector-Borne Disease Section: Program Overview ...............................................1

Vector-Borne Disease Section: Personnel ............................................................2

Rodent-borne Disease Surveillance ......................................................................3

Flea-borne Disease Surveillance ..........................................................................6

Tick-borne Disease Surveillance .........................................................................10

Mosquito-borne Disease Surveillance .................................................................15

Caltrans Stormwater Project Activities ................................................................28

U.S. Forest Service Activities ..............................................................................33

National Park Service Activities ...........................................................................45

Other Vectors and Public Health Pests ...............................................................48

Vector Control Technician Certification Program .................................................50

Presentations and Publications ...........................................................................52

Reports and Public Information Materials ...........................................................60

Acknowledgements .............................................................................................61

2008

ANNUAL REPORT

VECTOR-BORNE DISEASE SECTION

Table of Contents

1State of CaliforniaCalifornia Department of Public Health

June 2009


Vector-Borne Disease SectionProgram Overview

The mission of the California Department of Public Health (CDPH) Vector-Borne Disease Section (VBDS) is to protect the health and well-being of Californians from arthropod- and vertebrate-transmitted diseases and injurious pests. (Authorizing statutes: Health and Safety Code Sections116108-116120, 116102, et. seq., and 116180; Government Code Section 12582.) VBDS provides leadership, information, and consultation on vector-borne diseases to the general public and agencies engaged in the prevention and control of vector-borne diseases.

VBDS staff, located in six regional offices and headquartered in Sacramento, provide the following services:

Develop and implement statewide vector-borne disease surveillance, prevention, and control programs.Design and conduct scientific investigations to further knowledge of vector-borne diseases in California.Coordinate preparedness activities for detection and response to introduced vectors and vector-borne diseases, such as West Nile virus.Conduct emergency vector control when disease outbreaks occur.Administer public health exemptions in disease outbreaks where applicable under the Endangered Species Act.Advise local agencies on public health issues related to vector-borne diseases.Oversee local vector control agency activities through a Cooperative Agreement.Oversee the Vector Control Technician Certification and Continuing Education programs.Provide information, training, and educational materials to governmental agencies and the public.Provide assistance in coordinating issues related to the management of Africanized honey bees and red imported fire ants.Advise local governmental agencies, schools, and the public on head lice management.Maintain the San Francisco Bay Area U.S. Army Corps of Engineers general permit, which allows local vector control agencies to conduct abatement activities.Oversee Special Local Need permits on restricted use of public health pesticides.

This report summarizes surveillance and control activities for plague, hantavirus cardiopulmonary syndrome, and mosquito- and tick-borne diseases in 2008. Activities conducted in the National Forests and National Parks of California to protect U.S. Forest Service (USFS) and National Park Service (NPS) personnel and visitors from vector-borne diseases are included; USFS and NPS provide support for these activities through cooperative agreements. Results from a special project with the California Department of Transportation to examine vector production in stormwater treatment devices are described. VBDS oversees the Vector Control Technician Certification Program; data summarizing the number of exams administered by VBDS and the number of vector control technicians in each certification category are provided. As education and training are important components of a vector-borne disease prevention program, a summary of the many presentations and reports prepared by VBDS staff is included. Many of the federal, state, and local agencies with which VBDS collaborated in 2008 are listed in the Acknowledgements section.



June 2009Source: California Department of Public Health

Vector-Borne Disease SectionPersonnel

December 2008

Renjie Hu, Ph.D.

(Redding)Associate Public Health Biologist

Peter Bonkrude

Caltrans Agreement

U.S. Forest Service Project

(Elk Grove)Associate Public Health Biologist

Marco Metzger, Ph.D.Senior Public Health Biologist

Senior Public Health Biologist

(Santa Rosa)

Martin CastroAssociate Public Health Biologistjoseph Burns

Supervising Public Health Biologist

COASTAL REGIONStan Husted, M.P.H., M.P.A.

SOUTHERN REGION

Senior Public Health Biologist

(Ontario)

(Richmond)

(Richmond)

Richard Davis, D.Sc.Senior Public Health Biologist

(San Luis Obispo)


Kerry Padgett, Ph.D.

Michael Niemela, M.S.

DIVISION OF COMMUNICABLE DISEASE CONTROLDouglas Hatch, M.D., M.P.H., Chief

INFECTIOUS DISEASES BRANCH

NORTHERN REGIONMark Novak, Ph.D.

Supervising Public Health Biologist

Duc Vugia, M.D., M.P.H., Chief

VECTOR-BORNE DISEASE SECTIONVicki Kramer, Ph.D., Chief

Tina Feiszli, M.S.P.H.Associate Public Health Biologist

(Richmond)

Ervic Aquino, Data Manager


Linda Parsons

(Sacramento)

Associate Public Health Biologist

Denise Bonilla, M.S.

Long Her, Biologist

jesse Laxton

(Ontario)

(Elk Grove)

(Redding)

Lawrence BronsonSenior Public Health Biologist

(Elk Grove)Senior Public Health Biologist

james Tucker, M.S.

Mosquito Control Specialist

Tim Howard, M.S.

Anne Kjemtrup, D.V.M., M.P.V.M., Ph.D.

jonathan Kwan, M.S.

Research Scientist III (Epidemiology/Biostatistics)(Sacramento)

(Sacramento)

Senior Public Health Biologist(Sacramento)

(Ontario)

justin Harbison, M.S.

Claudia Erickson. M.S.Health Education Specialist(Sacramento, VBDS/VPHS)

Erin Parker, M.P.H., Biologist

Office Technician

Other VBDS staff during part of 2008: Carrie Nielsen, Ph.D., Vector Control Specialist (Sacramento)

Laboratory

Laura Diaz, MicrobiologistRobert Payne, Asst. Microbiologist

(Richmond)

Curtis Fritz, D.V.M., M.P.V.M., Ph.D.

HEADQUARTERS

Research Scientist IV (Epidemiology/Biostatistics)

(Sacramento)Administrative Analyst

(Sacramento)

janey Butner, Assistant ChiefINFECTIOUS DISEASES BRANCH

Supervising Public Health Biologist(Ontario)

(Richmond)

Associate Public Health Biologist(Richmond)

West Nile Virus Contract Project


June 2009


Rodent-borne Disease SurveillanceHuman disease surveillanceNo cases of hantavirus cardiopulmonary syndrome were diagnosed in California residents in 2008.

Non-human surveillanceRodentsIn 2008, 1102 rodents were collected and serologically tested for antibody to Sin Nombre virus (SNV), representing at least 10 species from 5 genera (Table 1). Of 1032 Peromyscus spp. collected, 48 (4.7 %) had serologic evidence of infection with SNV. Seroprevalence was highest in deer mice (Peromyscus maniculatus) at 11.5 percent. At least one seroreactive deer mouse was detected in 8 of 14 California counties in which surveillance was conducted in 2008 (Table 2).

VBDS activitiesThe California Department of Public Health (CDPH) Vector-Borne Disease Section (VBDS) continued three multi-year studies of hantavirus in rodent populations at National Forests in California. Summaries of results in 2008 from each of these studies are provided below.

Plumas National ForestEmploying mark-recapture methods, 216 rodents were captured over eight nights of trapping at the fire station study site in April, June, August, and October. Of 145 sera tested at the CDPH Viral and Rickettsial Disease Laboratory (VRDL), antibodies to SNV were detected in only one P. boylii. The overall infection prevalence of 0.7 percent was the lowest recorded since 2001 (4.7%). Rodent abundance, as measured by trap success, was down nearly 50 percent from 2007, with captures of P. maniculatus diminished from 75 in 2007 to 5 in 2008. The US Forest Service discontinued operations at the fire station in 2008, but the apparent rodent population crash cannot be wholly attributed to withdrawal of human activity as the same number of rodents were captured in sylvatic habitats adjacent to the facility as in and around structures during this season. It is likely that extreme drought conditions (4.25” rainfall for 2008) reduced forage production, limiting rodent reproduction as well as virus transmission.

Eldorado National ForestThree nights of trapping conducted at the fire station and fire lookout study sites in 2008 yielded 79 rodents--76 Peromyscus maniculatus, 2 Microtus longicaudus, and one P. boylii. The P. boylii represents only the second observation of this species at the fire station since the project began in 2002. The seroprevalence of SNV antibodies in P. maniculatus were 25, 20, and 17 percent at the fire station and 21, 20, and 9 percent at the lookout in June, August, and October, respectively. Recent habitat modification (tree and brush clearing) at the fire station likely reduced mouse abundance and activity around the facility; the SNV seroprevalence, however, remained higher than at the lookout and higher than the state average.

Inyo National ForestDuring six trap-night periods of a mark-recapture at the ranger station study site in May, June, and September 2008, a total of 50 P. maniculatus were captured, compared to 301 in 2006 and 190 in 2007. Overall seroprevalence for SNV was 24 percent (12 of 50), ranging from 75 percent (9 of 12) in May, to 14 percent (1 of 7) in late June, to 6 percent (2 of 31) in September. Seroprevalence in May was the highest recorded for the site since 2005, while seroprevalences in June and September’s were the lowest. The decline in seropositive deer mice as the year progressed recapitulated patterns seen in 2006 (37% in June to 21% in October) and 2007 (41% in May to 18% in September). The high seroprevalences observed at the beginning of the collection season support the hypothesis that older mice are more likely to be infected.




No. No. No. No.

Species Common name collected reactive Percent collected reactive Percent

FAMILY MURIDAE

Neotoma fuscipes dusky-footed woodrat 457 8 1.8

Neotoma lepida desert woodrat 19 0 0 525 18 3.4

Neotoma spp. other and unspecified Neotoma 1 0 0 89 0 0

Onychomys torridus southern grasshopper mouse 4 0 0

Peromyscus boylii brush mouse 217 1 0.5 2702 106 3.9

Peromyscus californicus parasitic mouse 124 0 0 1638 26 1.6

Peromyscus crinitus canyon mouse 34 1 3 331 11 3.3

Peromyscus eremicus cactus mouse 281 5 1.8 2324 84 3.6

Peromyscus maniculatus deer mouse 358 41 11.5 7641 1121 14.7

Peromyscus truei piñon mouse 18 0 0 445 14 3.1

Peromyscus sp. unspecified Peromyscus 100 12 12.0

Reithrodontomys megalotis western harvest mouse 44 4 9.1 756 66 8.7

Sigmodon hispidus hispid cotton rat 8 0 0

Microtus californicus California vole 224 28 12.5

Microtus spp. other and unspecified Microtus 4 0 0 117 11 9.4

SUBFAMILY MURINAE

Mus musculus house mouse 196 0 0

Rattus rattus black rat 61 0 0

FAMILY HETEROMYIDAE

Chaetodipus spp. pocket mice 2 0 0 495 3 0.6

Dipodomys spp. kangaroo rats 34 0 0

Perognathus spp. Great Basin pocket mouse 21 0 0

FAMILY SCIURIDAE

Ammospermophilus leucurus white-tailed antelope squirrel 2 0 0

Spermophilus spp. ground squirrels 1 0 0

Tamias spp. chipmunks 8 0 0

SUBFAMILY ARVICOLINAE

2008 1999-2008

SUBFAMILY SIGMODONTINAE

Table 1. Serologic evidence of hantavirus (Sin Nombre) infection in California rodents, 1999-2008.


June 2009


Source: California Department of Public Health

Table 2. Serologic evidence of hantavirus (Sin Nombre) infection in Peromyscus maniculatus in California, 1999-2008.

2008 1999-2008No. No. No. No.

County collected reactive Percent collected reactive PercentAlameda 17 0 0 152 1 0.7Alpine 76 26 34.2Amador 0Butte 13 5 38.5Calaveras 2 0 0 5 1 20.0Colusa 23 9 39.1Contra Costa 20 2 10.0Del Norte 0El Dorado 73 15 20.5 759 221 29.1Fresno 68 16 23.5Glenn 0Humboldt 0Imperial 0Inyo 77 7 9.1Kern 60 2 3.3Kings 0Lake 0Lassen 7 1 14.3 799 128 16.0Los Angeles 173 8 4.6Madera 42 10 23.8Marin 31 1 3.2Mariposa 5 1 20.0Mendocino 0Merced 0Modoc 19 0 0Mono 55 12 21.8 693 204 29.4Monterey 91 11 12.1Napa 67 8 11.9Nevada 34 7 20.6Orange 17 1 5.9 1162 73 6.3Placer 3 0 0Plumas 76 19 25.0Riverside 11 0 0 1558 205 13.2Sacramento 0San Benito 0San Bernardino 35 0 0 466 43 9.2San Diego 81 4 4.9 505 30 5.9San Francisco 13 0 0 13 0 0San Joaquin 0San Luis Obispo 48 6 12.5San Mateo 171 13 7.6Santa Barbara 84 13 15.5Santa Clara 21 0 0Santa Cruz 0Shasta 7 1 14.3 10 1 10Sierra 3 0 0 58 9 15.5Siskiyou 14 2 14.3 41 8 19.5Solano 0Sonoma 0Stanislaus 0Sutter 7 0 0Tehama 0Trinity 0Tulare 0Tuolumne 23 5 21.7 148 30 20.3Ventura 11 2 18.2Yolo 25 0 0Yuba 31 0 0Douglas, NV 5 1 20.0California 358 41 11.5 7650 1121 14.7



June 2009

Flea-borne Disease SurveillancePlagueThe California Department of Public Health (CDPH) collaborates with local, state, and federal agencies to conduct a statewide plague surveillance program. The CDPH Vector-Borne Disease Section (VBDS) collects, collates, and analyzes information on suspect and confirmed plague activity among humans, domestic pets, and wild animals throughout California. This report summarizes plague activity in California for 2008.

Human surveillanceNo cases of plague in humans were identified in California in 2008.

Domestic petsOne domestic cat with clinical signs suggestive of plague was tested through the public health Laboratory Response Network in 2008. The cat tested negative.

Wild animalsThrough the statewide plague surveillance program, blood samples were collected from 420 wild carnivores and 539 rodents from 39 California counties (Table 3, Figure 1). Seropositive carnivores were identified in Kern, Modoc, Plumas, Sierra, and Siskiyou counties; seropositive carnivores were 15 (4.8%) of 311 coyotes, and one bobcat from Kern County. Seroprevalence was highest (23%) among carnivores collected in Modoc County. One hundred and six feral pigs sampled from 12 counties were negative.

Blood samples were tested from 539 wild rodents collected in 21 California counties through the VBDS cooperative program. Antibodies to Yersinia pestis were detected in 9 (3%) of 302 California ground squirrels collected in 15 counties; all seropositive ground squirrels were from Inyo County. Additionally, one Lodgepole chipmunk and one Shadow chipmunk from Sierra County were seropositive.

Rodent plague surveillance conducted independently by the San Diego County Health Department detected Y. pestis antibodies in three California ground squirrels sampled from Doane Valley campground on Palomar Mountain.

One rabbit and one opossum tested for evidence of Y. pestis infection were negative.

FleasThree rodent flea-pools collected in Inyo County were negative for Y. pestis.


June 2009



Table 3. Mammals tested for plague in California, 2008. (All specimens are sera except where otherwise indicated.)

County

Location1 Species Result MonthAlameda 3Alpine 4Butte 3Colusa 1Contra Costa 1El Dorado 5 4GlennInyo 94Taboose Creek CG CA G Sq 1:1024 JuneTaboose Creek CG CA G Sq 1:1024 JuneTaboose Creek CG CA G Sq 1:256 JuneTaboose Creek CG CA G Sq 1:256 JuneTaboose Creek CG CA G Sq 1:32 JuneTaboose Creek CG CA G Sq 1:512 JuneTaboose Creek CG CA G Sq 1:512 JuneMillpond CoP and CG CA G Sq 1:128 JulyMillpond CoP and CG CA G Sq 1:256 JulyKern 29Frazier Park, 6.5W, Cuddy Valley Bobcat 1:128 MarchLake 26 5Lassen 22Los Angeles 7 42Mariposa 37Mendocino 29Modoc 12 35Lake City, 3N Coyote 1:64 JanuaryLake City, 3N Coyote 1:128 JanuaryLake City, 8NE Coyote 1:32 JanuaryFort Bidwell, 3S Coyote 1:128 JanuaryCedarville, 5SE Coyote 1:32 JanuaryCedarville, 6S Coyote 1:64 AprilCedarville, 6S Coyote 1:512 AprilAlturas, 5S Coyote 1:128 AprilMonterey 2 3Napa 13Nevada 17 4Orange 1Placer 8Plumas 15 28Vinton, 5SW Coyote 1:64 JanuaryVinton, 4SW Coyote 1:32 JanuaryRiverside 54San Benito 29San Bernardino 116 3San Diego 15 9San Francisco 1San Luis Obispo 31San Mateo 1Santa Barbara 18Santa Clara 8Shasta 22 6Sierra 5 22Sierraville, 3S Coyote 1:32 JanuaryBeckwourth, 3S Coyote 1:64 JanuaryCalpine, 4W Coyote 1:64 JanuaryTahoe NF, Sardine Lookout Lodgepole Chipmunk 1:64 JuneTahoe NF, Sardine Lookout Shadow Chipmunk 1:64 June

No. rodents tested

No.carnivores

tested

Positive specimens




County

Location1 Species Result MonthSiskiyou 89 41Callahan, 2.5E Coyote 1:128 FebruaryCallahan, 2.5E Coyote 1:64 FebruaryTehamaTulare 1Tuolumne 15 2Ventura 16Yolo 3Yuba 2California 121 48

No. rodents tested

No.carnivores

tested

Positive specimens

1. Mileage and direction from nearest town may be indicated2. Lymph node aspirate

AbbreviationsLocation CG: Campground CoP: County Park NF: National Forest Species CA G Sq: California ground squirrel (Spermophilus beecheyi)

Table 3. Continued.


June 2009



Figure 1. Mammals tested for evidence of Yersinia pestis, California, 2008. Icons indicate one or more positive specimens.



June 2009

Tick-borne Disease SurveillanceHuman disease surveillanceLyme diseaseA total of 78 cases of Lyme disease were reported to the California Department of Public Health (CDPH) in 2008. Case-patients were residents of 24 counties (Table 4). Mendocino County reported the most cases (11). Reported incidence was highest in Mendocino County at 12.7 cases per 100,000 residents (Figure 2). Of 44 cases for whom county of likely exposure was reported, 31 (70%) had exposure outside their county of residence; 28 of these reported exposure outside California. The most frequently reported locations of likely exposure were the states of Massachusetts and New York.

The median age of reported Lyme disease cases was 42 years (range: 2 to 84 years) and 46 (59%) were male. Of 67 cases for which race was reported, 65 (98%) were white, 1 was Native American, and 1 was listed as “Other.” Erythema migrans (EM) was identified in 45 (58%) cases. Of 40 cases with EM for which dates of onset were reported, 28 (70%) occurred between May and August.

Tick-borne relapsing feverEleven cases of tick-borne relapsing fever (RF) were reported to CDPH in 2008. Ages ranged from <1 year to 50 years and nine patients were male. Dates of onset ranged from mid January through early December; however, seven patients had onset between July and September. Case-patients were residents of six California counties; two case-patients were family members who lived in the same Nevada County home. Counties of likely exposure were El Dorado (2 cases), Inyo (2), Mono (2), Nevada (4), and Tuolumne (1).

Spotted Fever-Group RickettsiaIn July 2008, a male resident of Lake County presented with progressive swelling and erythema of his forearm which developed into a 1.5 cm eschar. DNA extracted from a biopsy of the eschar was positive for Rickettsia 364D by PCR at the Viral and Rickettsial Zoonoses Branch at the Center for Disease Control and Prevention (CDC). Although Rickettsia 364D had been previously reported in Pacific Coast ticks (Dermacentor occidentalis), this is the first known instance of human disease associated with this organism.

BabesiaIn September 2008, a 57-year-old, asplenic, sickle cell anemic, male resident of Alameda County was hospitalized following weakness, jaundice, renal failure, and decreased hemoglobin over the preceding month. Intraerythrocytic inclusions consistent with Babesia were observed on blood smear; infection with B. duncani was confirmed via polymerase chain reaction (PCR) performed by the Division of Parasitic Diseases, CDC. The patient was treated with clinidamycin and quinine and recovered. The patient had a history of receiving blood transfusions to treat the sickle-cell anemia; infection was evident on blood smears from July 2008 and the patient reported compatible clinical illness as early as June 2008. The American Red Cross, CDC, and CDPH Lab Field Services and VBDS collaborated to follow up on the donors whose blood was provided to the patient in 2008.

TularemiaTwo cases of tularemia were reported in 2008, both residents of Alameda County. A 54-year-old woman developed fever and cervical lymphadenopathy in September. An aspirate of the lymph node was positive for Francisella tularensis (type B) by PCR. The woman reported no contact with animals or arthropod bites, but reported hiking in Alameda and San Mateo counties during the week prior to onset. The second case, a 20-year-old man, had onset of fever, chills, and axillary pain after handling a wild rabbit from Solano County in November.


June 2009


Non-human surveillanceBorrelia spirochetesLocal, state, and federal agencies collaborated in 2008 to collect 4,675 western black-legged ticks (Ixodes pacificus) from 25 counties. Of these, 2,097 I. pacificus from 21 counties were tested by indirect fluorescent antibody assay (IFA), direct fluorescent antibody assay (DFA), or PCR for Borrelia spirochetes.

Of 1,875 adult I. pacificus tested, 18 pools (1.0%) from eight counties were positive for Borrelia spirochetes; of these, six were identified as B. burgdorferi (0.3%) by either specific antibodies (IFA) or by species-specific primers (PCR). Six of 652 (0.9%) adult ticks were positive in a DFA assay to generic Borrelia antibodies. Eleven pools tested by PCR were positive using B. burgdorferi-specific primers; five were positive only at Borrelia genus level.

Six pools of 222 I. pacificus nymphs (2.7%) tested from three counties contained Borrelia spirochetes, two of which (0.9%) were identified as B. burgdorferi by IFA or B. burgdorferi-specific PCR primers.

In 2008, VBDS staff conducted a study in Tilden Regional Park, Contra Costa County, to determine the risk of exposure to nymphal ticks at picnic sites from March through August. Nymphal Ixodes pacificus were collected March through July, with the peak in abundance in late April and a secondary peak in June. Nymphal I. pacificus were collected in greatest numbers in leaf litter, followed by vegetation, logs, wooden picnic tables, and tree trunks. This is the first study to identify wooden picnic tables as a source for potential tick exposure. Four of 170 (2.4%) nymphal I. pacificus collected at picnic sites were positive for Borrelia spirochetes by DFA.

In 2008, sera from 250 rodents collected in 12 counties were tested at Rocky Mountain Laboratories, National Institutes of Health, for antibodies to relapsing fever group Borrelia. Serum antibodies were detected in 2 of 41 Peromyscus spp., 3 of 101 Spermophilus spp., and 13 of 92 Tamias spp.

Spotted Fever-Group RickettsiaIn 2008, VBDS, Lake County Mosquito Vector Control District, and CDC conducted tick surveillance in Lake County as followup to the first diagnosed human infection with Rickettsia 364D. A total of 57 adult D. occidentalis, 14 adult Dermacentor variabilis, and 267 adult and nymphal Ornithodoros coriaceus were collected by flag or by CO2 traps. Rickettsia 364D was detected by PCR in 4 of 52 (7.7%) adult D. occidentalis. Non-pathogenic SFG Rickettsia were detected in 13 of 52 (25%) D. occidentalis; all other tick species were negative for SFG Rickettsia.

VBDS, CDC, and Los Angeles County Department of Public Health collaborated to collect 1,205 ticks in Los Angeles County along 17 hiking trails as well as residences of suspected canine Rocky Mountain spotted fever cases. Rickettsia 364D DNA was detected by PCR in 50 of 955 D. occidentalis. Rickettsia massiliae DNA was detected in 2 of 50 Rhipicephalus sanguineus collected from one household; this is the first time that this pathogen has been detected in California ticks.




Table 4. Reported Lyme disease cases by county of residence, California, 1999-2008.

County 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 Incidence per 100,000person-years

Alameda 3 4 3 5 1 0 5 3 2 6 0.21Alpine 0 0 0 0 0 0 0 0 0 0 0Amador 1 0 1 0 0 0 0 1 2 0 1.33Butte 18 3 1 3 2 2 0 1 0 2 1.50Calaveras 0 1 0 0 0 0 0 0 0 0 0.22Colusa 0 0 0 0 0 0 0 0 0 0 0Contra Costa 1 1 5 3 4 0 4 1 0 1 0.20Del Norte 1 0 0 2 0 0 0 0 0 0 1.04El Dorado 1 0 0 0 0 3 3 3 2 2 0.81Fresno 0 1 0 0 0 0 0 1 0 2 0.05Glenn 1 1 0 0 0 0 0 0 0 0 0.71Humboldt 14 10 4 4 5 7 11 5 7 6 5.57Imperial 0 0 0 0 0 0 0 0 0 0 0Inyo 0 0 1 0 0 0 0 1 0 0 1.08Kern 2 2 0 2 1 0 2 1 2 5 0.23Kings 0 0 0 0 0 0 0 0 0 0 0Lake 1 0 1 0 1 1 1 0 1 0 0.95Lassen 2 0 0 2 0 0 0 0 0 0 1.13Los Angeles 7 2 9 6 7 2 9 11 9 8 0.07Madera 1 0 0 0 0 0 0 0 0 0 0.07Marin 4 3 1 4 4 0 1 7 2 2 1.19Mariposa 0 0 0 1 0 1 0 0 0 0 1.12Mendocino 8 7 4 11 6 2 0 0 5 11 6.13Merced 1 1 0 0 0 0 0 0 0 0 0.08Modoc 0 0 0 0 0 0 0 0 0 0 0Mono 1 0 0 0 3 1 0 0 0 0 3.66Monterey 2 1 0 5 1 1 0 0 0 0 0.24Napa 2 2 3 3 0 1 1 0 3 0 1.13Nevada 5 9 6 3 4 1 3 2 3 2 3.85Orange 2 3 0 3 2 0 1 2 1 1 0.05Placer 2 1 4 3 0 2 2 3 0 1 0.59Plumas 1 0 1 0 0 0 0 0 0 0 0.95Riverside 0 3 2 1 2 1 4 0 0 1 0.07Sacramento 1 3 4 1 4 2 6 3 2 0 0.19San Benito 0 0 1 1 0 0 0 0 0 0 0.35San Bernardino 1 1 0 0 2 0 0 0 0 1 0.03San Diego 16 9 3 7 2 4 8 9 5 3 0.22San Francisco 1 2 3 3 3 1 7 5 5 4 0.43San Joaquin 0 0 0 0 0 0 0 0 0 0 0San Luis Obispo 1 1 0 0 0 0 1 0 0 1 0.15San Mateo 4 2 4 4 5 1 4 2 0 2 0.39Santa Barbara 0 0 1 2 2 2 0 0 2 2 0.26Santa Clara 2 2 2 6 4 0 2 9 2 0 0.16Santa Cruz 2 5 9 1 8 3 0 6 5 2 1.58Shasta 0 0 2 1 0 2 2 0 0 0 0.39Sierra 0 0 0 0 0 0 0 0 0 0 0Siskiyou 0 0 1 1 0 0 0 0 0 0 0.44Solano 0 1 1 0 0 0 0 0 0 0 0.05Sonoma 14 8 6 4 9 2 9 8 8 10 1.64Stanislaus 0 1 1 0 0 0 1 0 0 1 0.08Sutter 0 1 1 0 0 0 0 0 0 0 0.22Tehama 0 2 0 0 0 0 0 0 0 0 0.33Trinity 13 1 1 1 1 3 3 0 1 0 17.32Tulare 1 0 2 0 2 0 0 0 1 0 0.15Tuolumne 0 0 2 1 0 0 1 1 0 0 0.88Ventura 1 2 2 1 1 2 1 0 5 2 0.21Yolo 0 0 0 2 0 1 0 1 1 0 0.27Yuba 1 0 0 0 0 0 0 0 0 0 0.15California 139 96 92 97 86 48 94 86 76 78 0.24


June 2009



Figure 2. Reported incidence of Lyme disease by county of residence, California, 1999-2008.

Mendocino 12.7 > 5

Humboldt 4.7 > 3

Nevada 2.2

Sonoma 2.2

El Dorado 1.2 > 1

Others > 0

2008

Reported cases per 100,000 person-years

Trinity 17.3

Mendocino 6.1

Humboldt 5.6 > 5

Nevada 3.8

Mono 3.7 > 3

Sonoma 1.6

Santa Cruz 1.6

Butte 1.5

Amador 1.3

Marin 1.2

Lassen 1.1

Napa 1.1

Mariposa 1.1

Inyo 1.1

Del Norte 1.0 > 1

Others > 0 1999-2008

Reported cases per 100,000 person-years




Table 5. Ixodes pacificus ticks tested for evidence of Borrelia spirochetes, California, 2008.

No. pools positiveNo ticks No. pools DFA IFA PCR

County Location tested tested Borrelia spp. B. burgdorferi Borrelia spp. B. burgdorferi** Laboratory

Alameda Indian Joe Trail 32 32 0 CDPH-VBDSLittle Yosemite Area 4 4 0 CDPH-VBDS

Amador Grinding Rock SP 31 4 1 US ArmyCalaveras Natural Bridge 103 11 4 3 US Army

Water Treatment Site 13 4 0 US ArmyContra Costa Tilden Regional Park 140 (182*) 140 (182*) 1 (4*) CDPH-VBDSLake Mendocino NF 190 (2*) 19 (1*) 4 US Army

Mendocino NF 9* 9* 0 CDPH-VBDSMiddletown 5 (3*) 5 (3*) 0 CDPH-VBDS

Los Angeles Angeles NF 59 59 0 CDPH-VBDSCharmlee Wilderness 117 117 0 CDPH-VBDSMalibu 100 10 0 US Army

Madera Chepo Saddle 2 (1*) 1 (1*) 0 US ArmyMarin Point Reyes NS 7 (3*) 7 (3*) 0 CDPH-VBDS

Marin Headlands 69 69 3 CDPH-VBDSMariposa Sierra NF 20 2 0 US ArmyMendocino Manchester SB 26 26 0 CDPH-VBDSNapa Bale Grist Mill SHP 67 67 0 Napa MAD

R.L. Stevenson SP 100 100 0 Napa MADQuail Ridge Reserve 142 (8*) 14 (1*) 1 (1*) Sac-Yolo MVCD

Nevada Nevada City 17 (8*) 11 (2*) 0 US ArmyRiverside San Bernardino NF 49 (1*) 49 (1*) 0 CDPH-VBDSSan Bernardino San Bernardino NF 6 2 0 US ArmySan Diego Cleveland NF 24 3 0 US Army

Cleveland NF 23 23 0 CDPH-VBDSSan Joaquin Carnegie SP 22 8 0 US ArmySanta Clara Henry Coe SP 100 (11*) 10 (1*) 2 (1*) 2 (1*) CDPH-VBDSSanta Cruz Pogonip SP 42 42 1 CDPH-VBDSShasta Anderson River Park 38 4 0 US Army

Baily Cove CG 18 2 0 US ArmyAnderson 51 5 0 US ArmyRedding 70 7 0 US Army

Solano Cold Canyon Reserve 61 61 1 CDPH-VBDSCold Canyon Reserve 106 (2*) 10 (1*) 0 Sac-Yolo MVCD

Stanislaus Patterson 3 2 0 US ArmyTotal ticks tested 1843 (222*) 916 (204*) Total pools positive 6 (4*) 1 (1*) 11 (1*) 5 (1*)

* Nymphs** PCR primer sets were specific for B. burgdorferi Test: DFA, Direct Fluorescent Antibody

PCR, Polymerase Chain ReactionCG, CampgroundNF, National ForestNS, National SeashoreSB, State BeachSHP, State Historic ParkSP, State Park

Laboratory: US Army, United States Army Center for Health Promotion and Preventive Medicine-West CDPH-VBDS, California Department of Public Health, Vector-Borne Disease SectionNapa MAD, Napa County Mosquito Abatement DistrictSac-Yolo MVCD, Sacramento Yolo Mosquito Vector Controd District


June 2009


Mosquito-borne Disease SurveillanceThe California Arbovirus Surveillance program is a cooperative effort of the California Department of Public Health (CDPH), the University of California at Davis Center for Vectorborne Diseases (CVEC), the Mosquito and Vector Control Association of California (MVCAC), local mosquito abatement and vector control agencies, county and local public health departments, and physicians and veterinarians throughout California. Additional local, state, and federal agencies collaborated upon, and contributed to, the West Nile virus (WNV) component of the arbovirus surveillance program. (See Acknowledgements, page ii)

In 2008, the surveillance program elements included:

1. Diagnostic testing of specimens from human patients exhibiting symptoms of encephalitis, aseptic meningitis, acute flaccid paralysis, or with unexplained febrile illness of more than seven days.

2. Diagnostic testing of specimens from horses exhibiting clinical signs of viral neurologic disease compatible with western equine encephalomyelitis virus (WEE), WNV, and other arboviruses as appropriate.

3. Monitoring and testing of mosquitoes for the presence of St. Louis encephalitis (SLE), WEE, West Nile, and other arboviruses as appropriate.

4. Serological monitoring of sentinel chickens for SLE, WEE, and WNV antibodies.5. Surveillance and diagnostic testing of tree squirrels and dead birds, especially crows and other

birds in the family Corvidae, for infection with WNV.6. Weekly reporting in the CDPH Arbovirus Surveillance Bulletin of arbovirus testing results in

California and arbovirus activity throughout the United States.7. Bi-weekly posting of WNV information, including test results, reports, maps, and public

education materials on the California WNV website: www.westnile.ca.gov.8. Mapping of dead bird reports using the WNV Dynamic Continuous-Area Space-Time (DYCAST)

model.9. Data management and reporting through the web-based California Surveillance Gateway.

Human disease surveillance Serological diagnosis of human infection with WNV and other arboviruses was performed at the CDPH Viral and Rickettsial Disease Laboratory (VRDL) and 26 local county public health laboratories. Local laboratories tested for WNV using an IgM or IgG immunofluorescent assay (IFA) and/or an IgM enzyme immunoassay (EIA). Specimens with inconclusive results were forwarded to the VRDL for confirmation or further testing with a plaque reduction neutralization test (PRNT). Additional WNV infections were identified through testing performed at blood donation centers.

A total of 445 symptomatic and 53 asymptomatic--including 51 blood donors--infections with WNV were identified in 2008 (Table 6). The 445 clinical WNV cases occured among residents of 27 counties; incidence was highest (6.4 cases per 100,000 persons) in Tehama County (Figure 3). Of these, 148 (33%) were classified clinically as West Nile fever, 293 (66%) were neuroinvasive disease (i.e. encephalitis, meningitis, or acute flaccid paralysis), and four (1%) were of unknown clinical presentation. For cases for which data were available, 283 (64%) were male and the median age was 55 years (range: 3-94 years). The median ages for West Nile fever and neuroinvasive cases were 52 years (range: 7-94 years) and 58 years (range: 3-90 years), respectively. The median age of the 15 WNV-associated fatalities was 78 years (range: 48-90 years).



June 2009

Horse surveillanceSera or brain tissue from horses displaying neurological signs were tested for arboviruses at the California Animal Health and Food Safety Laboratory System (CAHFS) and CVEC. West Nile virus infections were detected in 32 horses from 14 counties (Table 7). At the time of onset, five horses were currently vaccinated with the WNV vaccine, two had not completed the recommended vaccine dosage schedule, and 14 were unvaccinated; vaccination history was unknown for 11 horses. Seventeen (53%) of the horses died or were euthanized as a result of their illness.

Mosquito surveillance Forty-three agencies in 33 counties collected a total of 798,048 mosquitoes (26,285 pools) which were tested by real-time polymerase chain reaction (RT-PCR) for SLE, WEE, and WNV RNA (Table 8) at CVEC and the Sacramento-Yolo Mosquito and Vector Control District. An additional 182,894 mosquitoes (8,817 pools) were tested for only WNV by eight local agencies using either RT-PCR or a commercial rapid assay-RAMP® (Rapid Analyte Measurement Platform, Response Biomedical Corp; Table 9).

WNV was identified from six Culex species (Cx. erythrothorax, Cx. pipiens, Cx. quinquefasciatus, Cx. restuans, Cx. stigmatosoma, Cx. tarsalis) and two Culiseta species (Culiseta incidens, Culiseta inornata) (Table 4). West Nile virus was detected in 1,999 of 32,115 Culex spp. pools from 27 counties (Table 9, Figure 4); 1,639 were positive by RT-PCR and 360 were positive by RAMP only. The first detection of WNV in mosquitoes in 2008 was from a pool of Culex erythrothorax collected on February 12 in Orange County. The last detection of WNV in mosquitoes in 2008 was from a pool of Cx. quinquefasciatus collected on December 12 in Los Angeles County. SLE and WEE viruses were not detected in mosquito pools in 2008 (Figure 5).

Sentinel chicken surveillanceFifty-three local mosquito and vector control agencies in 40 counties maintained 246 sentinel chicken flocks (Table 8). Blood samples were collected from chickens every other week and tested for antibodies to flavivirus and alphavirus by EIA. Antibodies to SLE, WNV, or WEE were confirmed by IFA and western blot.

Laboratories at the CDPH Vector-Borne Disease Section (VBDS) and four local mosquito and vector control agencies tested 31,225 chicken sera for antibodies to SLE, WEE, and West Nile viruses. A total of 585 seroconversions to WNV were detected among 129 flocks from 27 counties (Table 8, Figure 6). In 2008, the first and last WNV seroconversions were detected in Los Angeles County on January 29 and December 18, respectively. No SLE or WEE seroconversions were detected in 2008 (Figure 7).

Dead bird and tree squirrel surveillanceIn 2008, the WNV hotline and website received 33,684 dead bird reports from the public in all 58 counties. Of the 6,100 carcasses deemed suitable for testing, WNV was detected in 2,568 (42%) carcasses from 46 counties: 2,235 by RT-PCR at CVEC and two local agencies, 208 by VecTest and 96 by RAMP at 23 local agencies, and 29 by immunohistochemistry at CAHFS (Table 10, Figure 8). In 2008, the first and last WNV positive dead birds were reported in San Diego County on January 7 and December 27, respectively. Reports of dead birds were mapped onto a 0.25 square-mile scale grid and analyzed using the DYCAST model. Clusters of reported dead birds were interpreted as suggestive of increased WNV activity. Areas of possibly increased WNV activity were identified in 21 counties; in six of these, dead bird clusters were the first potential indicators of WNV activity in 2008.

In 2008, 691 dead tree squirrels were reported through the WNV hotline; 219 carcasses were tested and WNV RNA was detected in 33 (15%) carcasses from seven counties (Table 7). These included 27 eastern fox squirrels (Sciurus niger), 5 eastern gray squirrels (S. carolinensis), and one western gray squirrel (S. griseus).


June 2009



Table 6. Reported cases of West Nile virus infection by county of residence, California, 2004-2008.

County 2004 2005 2006 2007 2008Incidence per 100,000

person-yearsAlameda 0 1 1 0 1 0.0Alpine 0 0 0 0 0 0.0Amador 0 3 0 0 0 1.6Butte 7 24 31 16 6 7.8Calaveras 0 2 0 0 1 1.3Colusa 0 2 4 2 1 8.5Contra Costa 0 11 8 3 4 0.5Del Norte 0 0 0 0 0 0.0El Dorado 0 1 2 0 1 0.5Fresno 11 59 11 17 3 2.3Glenn 3 13 12 7 1 25.3Humboldt 0 1 0 0 0 0.2Imperial 1 1 1 3 0 0.7Inyo 0 0 0 0 0 0.0Kern 59 67 49 140 2 8.2Kings 0 32 1 7 2 5.7Lake 1 0 2 0 0 0.9Lassen 1 0 0 0 0 0.6Los Angeles 306 40 13 36 156 1.1Madera 0 18 0 2 0 2.8Marin 0 0 1 0 0 0.1Mariposa 0 0 0 0 0 0.0Mendocino 0 0 0 2 0 0.4Merced 1 25 4 4 1 2.9Modoc 0 0 2 0 0 4.1Mono 0 0 1 0 0 1.5Monterey 0 0 0 0 0 0.0Napa 0 0 1 1 0 0.3Nevada 0 4 1 0 0 1.0Orange 62 17 6 9 71 1.1Placer 1 35 8 4 6 3.4Plumas 0 1 0 0 0 0.9Riverside 109 103 4 17 62 3.0Sacramento 3 163 15 25 13 3.2San Benito 0 0 0 0 0 0.0San Bernardino 187 33 3 4 36 2.6San Diego 2 1 1 15 35 0.4San Francisco 0 2 0 0 0 0.0San Joaquin 2 34 8 10 12 2.0San Luis Obispo 1 0 1 0 0 0.2San Mateo 0 1 0 0 0 0.0Santa Barbara 0 2 0 0 1 0.1Santa Clara 1 5 5 4 1 0.2Santa Cruz 0 0 0 0 0 0.0Shasta 5 1 4 9 1 2.2Sierra 0 0 0 0 0 0.0Siskiyou 0 0 0 0 0 0.0Solano 0 5 8 1 1 0.7Sonoma 0 1 0 1 0 0.1Stanislaus 0 84 11 21 17 5.2Sutter 0 9 12 3 0 5.3Tehama 10 4 6 4 4 9.2Trinity 0 0 0 0 0 0.0Tulare 3 56 6 10 5 3.8Tuolumne 0 1 0 0 0 0.4Ventura 2 1 3 1 0 0.2Yolo 1 11 27 2 1 4.4Yuba 0 6 5 0 0 3.2

Total WNV disease 779 880 278 380 445 1.5Asymptomaticinfections 51 55 14 29 53

Total WNV infections 830 935 292 409 498 1.6




Table 7. Infections with West Nile virus in California, 2008.

County Humans HorsesaMosquito

poolsSentinelchickens

Deadbirds

Deadsquirrels

Alameda 1 1 0 12 1Alpine 0 --- --- --- ---Amador 0 --- --- 3 0Butte 7 5 31 38 0Calaveras 1 1 9 1 0Colusa 1 --- 1 3 ---Contra Costa 5 3 31 15 88 7Del Norte 0 --- --- 1 ---El Dorado 1 --- --- 9 0Fresno 3 1 53 24 44 1Glenn 1 1 5 17 ---Humboldt 0 --- --- 1 ---Imperial 0 7 26 --- ---Inyo 0 --- --- 0 ---Kern 2 7 18 10 0Kings 2 0 1 1 ---Lake 0 1 3 1 2 ---Lassen 0 1 --- 0 ---Los Angeles 179 517 134 481 14Madera 0 1 2 3 ---Marin 0 0 0 1 0Mariposa 0 --- --- 0 ---Mendocino 0 --- --- 1 0Merced 1 1 0 3 5 ---Modoc 0 --- --- 1 ---Mono 0 --- --- 2 ---Monterey 0 --- 0 6 ---Napa 0 0 0 1 0Nevada 0 --- 0 5 0Orange 79 2 361 3 639 4Placer 6 1 27 11 4 0Plumas 0 --- --- 0 ---Riverside 64 9 118 118 39 ---Sacramento 17 3 277 7 130 1San Benito 0 --- 0 0 ---San Bernardino 42 2 170 61 176 5San Diego 36 4 40 15 566 ---San Francisco 0 --- --- 0 ---San Joaquin 15 207 18 69 ---San Luis Obispo 0 --- --- 2 0San Mateo 0 --- 0 2 0Santa Barbara 1 0 0 1 ---Santa Clara 1 1 0 13 0Santa Cruz 0 0 0 3 0Shasta 1 0 3 7 ---Sierra 0 --- --- 0 ---Siskiyou 0 --- --- 0 0Solano 2 1 7 7 ---Sonoma 0 2 0 11 0Stanislaus 18 2 75 38 45 ---Sutter 0 12 9 2 ---Tehama 5 --- 0 6 0Trinity 0 --- --- 1 ---Tulare 5 1 64 20 76 ---Tuolumne 0 --- --- 0 0Ventura 0 1 0 4 24 ---Yolo 1 1 19 0 9 0Yuba 1 1 1 0 ---California 498 32 2003 585 2568 33

aData not available for horses that tested negative for WNV--- None tested


June 2009



Table 8. Mosquitoes and sentinel chickens tested for St. Louis encephalitis (SLE)a, western equine encephalomyelitis (WEE), and West Nile (WNV) viruses, California, 2008.

CountyNo. mosquitoes

testedbNo. mosquito pools tested

WNV + pools

No.flocks

No.chickens

No. sera testedc

WNV + sera

Alameda 7,411 229 1 3 21 224 0Alpine 0 0Amador 0 0Butte 3,223 74 5 7 77 1,193 31Calaveras 0 1 10 138 9Colusa 0 1 10 138 1Contra Costa 14,859 396 6 5 55 708 15Del Norte 0 0El Dorado 0 0Fresno 25,767 762 46 10 111 1,304 24Glenn 1,641 34 1 1 13 175 5Humboldt 0 0Imperial 9,052 190 7 6 72 525 26Inyo 0 0Kern 19,743 660 7 15 188 2,102 18Kings 15,089 406 0 4 24 270 1Lake 9,622 215 3 2 30 270 1Lassen 730 19 1 0Los Angeles 124,559 3,474 506 47 331 4,860 134Madera 952 20 1 2 22 252 2Marin 822 44 0 1 6 59 0Mariposa 0 0Mendocino 0 0Merced 9,985 320 0 8 58 572 3Modoc 0 0Mono 0 0Monterey 0 2 22 340 0Napa 5,099 117 0 3 33 390 0Nevada 0 2 20 320 0Orange 0 1 10 155 3Placer 30,393 969 27 8 48 592 11Plumas 0 0Riverside 120,670 3,118 118 22 271 3,343 118Sacramento 159,180 7,397 276 7 42 1,465 7San Benito 0 1 10 147 0San Bernardino 28,199 1,223 49 18 126 2,295 61San Diego 8,545 279 40 4 40 592 15San Francisco 0 0San Joaquin 4,541 148 1 2 20 279 18San Luis Obispo 0 0San Mateo 0 1 10 130 0Santa Barbara 14,016 327 0 4 39 682 0Santa Clara 712 169 0 4 40 548 0Santa Cruz 6,446 146 0 2 20 303 0Shasta 3,248 66 0 7 74 919 3Sierra 0 0Siskiyou 0 0Solano 4,766 111 1 3 36 315 7Sonoma 1,295 64 0 2 12 168 0Stanislaus 50,542 1,754 63 9 100 1,236 38Sutter 11,012 271 12 5 50 635 9Tehama 0 3 40 337 0Tulare 27,743 698 64 8 90 1,003 20Tuolumne 0 0Ventura 1,637 43 0 5 49 839 4Yolo 75,894 2,524 18 8 48 1,164 0Yuba 655 18 1 2 20 238 1California 798,048 26,285 1,254 246 2,298 31,225 585

aNo mosquito pools or sentinel chickens were positive for SLE or WEE in 2008

cTested by California Department of Public Health Vector Borne Disease Laboratory or local mosquito/vector control agencies

bTested by University of California at Davis Center for Vectorborne Diseases or local mosquito/vector control agency. Does not includemosquitoes tested by local agencies for WNV only.




Table 9. Mosquitoes tested for West Nile virus (WNV), California, 2008.Culex species Pools Mosquitoes WNV + Prevalencea

Cx boharti 1 1 0 0Cx erraticus 6 126 0 0Cx erythrothorax 2,068 77,360 22 0.28Cx pipiens 8,055 186,351 340 1.82Cx quinquefasciatus 7,820 244,092 1,046 4.29Cx restuans 5 94 1 10.64Cx stigmatosoma 753 8,660 67 7.74Cx tarsalis 13,390 422,438 523 1.24Cx thriambus 16 559 0 0Cx unknown 1 11 0 0All Culex 32,115 939,692 1,999 2.13

Anopheles species Pools Mosquitoes WNV + PrevalenceAn franciscanus 43 362 0 0An freeborni 153 4,318 0 0An hermsi 60 1,170 0 0An occidentalis 7 93 0 0An punctipennis 49 154 0 0All Anopheles 312 6,097 0 0

Aedes species Pools Mosquitoes WNV + PrevalenceAe dorsalis 153 3,137 0 0Ae increpitus 4 167 0 0Ae melanimom 304 8,903 0 0Ae nigromaculis 12 191 0 0Ae sierrensis 22 164 0 0Ae squamiger 26 217 0 0Ae taeniorhynchus 58 2,805 0 0Ae vexans 61 2,212 0 0Ae washinoi 172 3,038 0 0All Aedes 812 20,834 0 0

Other species Pools Mosquitoes WNV + PrevalenceCuliseta incidens 1,264 10,116 3 0.30Culiseta inornata 337 1,356 1 0.74Culiseta particeps 177 1,113 0 0Coquilletidia peturbans 65 1,341 0 0Unknown species 20 393 0 0All other 1,863 14,319 4 0.28

a Prevalence = (No. pools positive/No. mosquitoes tested) X 1000


June 2009



Table 10. Dead birds reported, testeda, and positive for West Nile virus, California, 2008.

County Reported Tested PositivePercentPositive

Alameda 678 128 12 9.4Alpine 3 0 0 ---Amador 100 25 3 12.0Butte 751 139 38 27.3Calaveras 129 28 1 3.6Colusa 46 7 3 42.9Contra Costa 2185 321 88 27.4Del Norte 12 3 1 33.3El Dorado 477 89 9 10.1Fresno 1199 172 44 25.6Glenn 92 37 17 45.9Humboldt 58 6 1 16.7Imperial 25 0 0 ---Inyo 35 7 0 0.0Kern 1552 194 10 5.2Kings 133 10 1 10.0Lake 83 11 2 18.2Lassen 23 3 0 0.0Los Angeles 5426 922 481 52.2Madera 104 28 3 10.7Marin 219 28 1 3.6Mariposa 16 2 0 0.0Mendocino 79 16 1 6.3Merced 207 32 5 15.6Modoc 15 2 1 50.0Mono 11 3 2 66.7Monterey 258 42 6 14.3Napa 88 3 1 33.3Nevada 305 59 5 8.5Orange 3006 965 639 66.2Placer 713 17 4 23.5Plumas 57 16 0 0.0Riverside 1232 92 39 42.4Sacramento 3062 420 130 31.0San Benito 34 5 0 0.0San Bernardino 1544 330 176 53.3San Diego 1688 818 566 69.2San Francisco 106 15 0 0.0San Joaquin 1495 199 69 34.7San Luis Obispo 169 30 2 6.7San Mateo 379 73 2 2.7Santa Barbara 95 15 1 6.7Santa Clara 948 93 13 14.0Santa Cruz 163 30 3 10.0Shasta 406 20 7 35.0Sierra 16 1 0 0.0Siskiyou 21 3 0 0.0Solano 542 22 7 31.8Sonoma 489 89 11 12.4Stanislaus 924 130 45 34.6Sutter 179 8 2 25.0Tehama 112 31 6 19.4Trinity 14 3 1 33.3Tulare 752 180 76 42.2Tuolumne 92 8 0 0.0Ventura 552 102 24 23.5Yolo 482 60 9 15.0Yuba 103 8 0 0.0Totals 33,684 6,100 2,568 42.1aTested by University of California at Davis Center for Vectorborne Diseases or local mosquito/vector control agency




Figure 3. Human cases of West Nile virus (WNV) infection, California, 2008.

1

1

113

6

124

117

1

52

236

156

71 62

35

County

Tehama 6.4Colusa 4.6Glenn 3.4Stanislaus 3.2Riverside 3.0Butte 2.7Orange 2.3Calaveras 2.2Placer 1.8San Joaquin 1.8San Bernardino 1.8Los Angeles 1.5Kings 1.3Tulare 1.2San Diego 1.1

Others

Incidence per 100,000 population

> 3

> 0

> 1

> 5

4

1

1

6

3

##: Number of WNV cases identified

1

1

1

1


June 2009



Figure 4. West Nile virus in Culex spp. mosquitoes, California, 2008. Prevalence = (number of positive pools/number of mosquitoes tested) X 1,000.

Prevalence of West Nile virus

> 5.0

No Culex tested

0

0.1 – 1.0

1.1 – 3.0

3.1 – 5.0

0.4

0.6

3.0

10.5

1.0

0.84.7

1.1

2.3

4.2

2.0

2.9

1.20.1

1.60.6

0.4 1.2

0.3 0.3

1.3

1.8

1.51.1

5.0

1.4

0.2




Figure 5. Mosquito pools tested for St. Louis encephalitis (SLE), western equine encephalitis (WEE), and West Nile (WNV) viruses, California, 1999-2008. (Mosquito pools were tested for WNV beginning in 2000.)

0.8

2

0.2 0.050.6

0.30.05 0.04

0.3

7.6

6.2

3.23.6

4.8

0123456789

10

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008Year

Mo

sq

uit

o p

oo

ls,

perc

en

t p

osit

ive SLE

WEEWNV


June 2009



Figure 6. West Nile virus (WNV) seroconversions in sentinel chicken flocks, California, 2008.

Percent of sentinel flocks in which >1chickens seroconverted to WNV

>75%

51 - 75 %

No flocks maintained

No seroconversions

1 - 25 %

26 - 50 %

##: Number of flocks maintained

4

22

18

4

6

1

47

15

54

84

102

2

1

4

2

13

2

13

28

7

3

2

8

5

8

7

2571

1

3

9

12




Figure 7. Sentinel chicken seroconversions to St. Louis encephalitis (SLE), western equine encephalitis (WEE), and West Nile (WNV) viruses, California, 1999-2008. (Sentinel chickens were tested for WNV beginning in 2000.)

1.42.7 3.5

2.20.60.2 0.2

2.6

0.1

5.3

0.6 0.6

3.2

30.3 30.429.1

23.3

25.6

0

5

10

15

20

25

30

35

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008Year

Sero

co

nvers

ion

s,

perc

en

t o

f sen

tin

el

ch

icken

s

SLEWEEWNV


June 2009



Figure 8. West Nile virus infection in dead birds, California, 2008.

Percent of dead birds in which WNV was detected

0%

1 -19 %

>60%

40 - 59 %

20 - 39 %

No birds tested



June 2009

Caltrans Stormwater Project ActivitiesIntroduction and backgroundIn 1999, the California Department of Public Health, Vector-Borne Disease Section (VBDS), entered into a Memorandum of Understanding with the California Department of Transportation (Caltrans). The interagency agreement that followed tasked VBDS to lend technical expertise to the Caltrans Stormwater Program regarding vector production (chiefly mosquitoes) and the potential for vector-borne diseases within structural treatment Best Management Practices (BMPs) installed along state highways to reduce pollution carried by stormwater runoff. To this end, VBDS has designed, implemented, and evaluated surveillance and research projects intended to minimize vector production in Caltrans BMPs while maintaining water management and water quality goals. The interagency agreement has been revised and renewed three times since its inception. Funding has been used to support at least two full-time VBDS staff and has supported five interns under the California Epidemiologic Investigation Service Fellowship Program.

In 1999-2001, VBDS’s chief activity was to document and, where possible, recommend non-chemical measures to minimize vector production within BMPs in Los Angeles and San Diego counties. Data revealed that a large percentage of BMPs, particularly those that held permanent standing water, produced mosquitoes. A nationwide survey conducted by VBDS of over 150 public agencies supported these findings. Various design changes, specific repairs, exclusion techniques, biological controls, and maintenance intervals were developed and implemented to minimize mosquito breeding.

Additional projects were conducted in 2002-2007 to better understand the relationship of mosquitoes with stormwater BMPs, develop new mosquito control measures, and improve upon previously implemented solutions. The long-term projects in Los Angeles and San Diego counties continued, while several special studies indicated that BMPs in the Lake Tahoe Basin supported mosquitoes during summer months when natural habitats are dry. In addition, studies in this region indicated that water could be held in BMPs for up to 96 hours without contributing to mosquito breeding. A summer project in Los Angeles suggested that structural barriers or routine insecticide treatment were the most viable options for mosquito control in subterranean BMPs. Results from all studies were published in interagency reports, magazine articles, and peer-reviewed journals and are used as reference materials both in California and nationally to guide policy.

Consultation and education services have been a vital component of the interagency agreement since its inception. VBDS has provided Caltrans with periodic review of BMP pre-construction plans, current information on vector minimization practices specific to stormwater infrastructure, information on vector biology and vector-borne diseases, and information on personal protective measures for employee health and safety. These services have been provided through a variety of media including seminars, field demonstrations, brochures, electronic mail, and personal communication.

Project activities: 2008Summary

• Extended the current interagency agreement funding through June 30, 2009.• Initiated negotiations for a proposed three-year renewal of the interagency agreement. • Continued biweekly inspections of BMPs installed along State Route (SR) 73 in Orange County.• Prepared biweekly reports of observations and recommendations related to mosquito production in

SR-73 BMPs.• Initiated a multi-year study of BMPs installed along a newly-constructed 11-mile segment of the

SR-125 freeway in San Diego County.• Prepared monthly reports of observations related to mosquito production in SR-125 BMPs.


June 2009


• Continued to gather responses to a nationwide survey of mosquito control and stormwater management agencies and began compiling and analyzing data.

• Initiated and completed special studies on the biology, ecology, and control of Culex quinquefasciatus mosquitoes in subterranean BMPs.

• Continued collaboration with local vector control agencies conducting vector surveillance at selected BMP sites.

• Maintained a database on larval mosquito abundance in BMPs that were monitored by VBDS and collaborating vector control agencies.

• Presented seminars on issues pertaining to BMPs and vector production at professional meetings, continuing education seminars, and informal meetings.

• Prepared, submitted, and published manuscripts on surveillance projects and research studies.

SR-73 Project, Orange CountyVBDS continued bimonthly monitoring of 24 BMPs installed along SR-73 in Orange County for evidence of vector production or conditions favorable to vector production. The majority of structural modifications made to BMPs by Caltrans in 2005 continued to be successful in minimizing mosquito breeding sites. Available mosquito habitat was greatly reduced, except where persistent non-stormwater flows created situations difficult to control. Key findings from four years of study (June 2004-June 2008) were:

• The percentage of BMPs failing to drain within 96 hours of a storm event increased notably during months with greater than 20 mm total rainfall, suggesting the need for additional improvements to design and maintenance.

• The percentage of BMPs with observed standing water remained consistently between 10 and 25 percent from mid 2005 through 2008 despite two seasons with below-average rainfall and extended periods of drought. These data were mostly a result of persistent non-stormwater flows entering certain BMPs.

• At no point were all BMPs completely dry. The fewest number of BMPs with standing water was observed in June 2008 when only one site that received persistent non-stormwater flow contained standing water.

• Mosquitoes were present in approximately 15 percent of those BMPs in which standing water was present.

• Mosquitoes were observed in standing water in BMPs during all months of the year except December, but were most commonly seen during periods when BMPs received chiefly non-stormwater flow, viz. June to September (Figure 9).

SR-125 Project, San Diego CountyIn 2008, the 11-mile SR-125 toll road in San Diego County was opened for public use. Sixty-four stormwater BMPs were installed within this transportation corridor: 33 grass swales, 15 extended detention basins (EDB), and 16 belowground proprietary systems named Aqua-Filter™ (manufactured by AquaShield™ Inc.). Initial observations by VBDS in April confirmed the presence of mosquitoes at several EDBs and Aqua-Filters™. These types of BMPs had features highly favorable to mosquito production in sub-grade riprap energy dissipaters (depressions filled with large rocks) and in underground chambers with permanent standing water. Monthly data collection for EDBs and Aqua-Filters™ began in July to document presence of standing water, presence of mosquitoes, and mosquito species composition, and to identify sources and/or causes for standing water. Findings will be used to develop long-term, non-chemical solutions to minimize mosquito production in these BMPs, many of which are near densely populated residential areas and sport parks.

Nationwide SurveyIn late 2007, VBDS launched a nationwide survey of stormwater management and vector control agencies to complement a survey conducted in 2001. The objective was to determine if the arrival and spread of West Nile virus (WNV) in North America had catalyzed widespread policy change with



June 2009

regard to mosquito control in stormwater management structures. In addition, it was hypothesized that BMPs, largely unrecognized by vector control agencies in 2001, would now be prioritized for mosquito control activities. A 34-question, internet-based questionnaire was prepared to solicit information on 1) the prevalence and types of BMPs that produce mosquitoes, 2) efforts taken to minimize mosquito production in these structures, 3) the costs of associated mosquito management measures, 4) public health policy changes in response to the introduction and spread of WNV, and 5) identification of additional needs of stormwater management and vector control agencies to prevent future vector-borne diseases crises. Findings will aid development of future Caltrans policies on mosquito and vector control in stormwater BMPs.

A total of 585 agencies in 50 states and the District of Columbia were contacted. The internet link to the questionnaires was mailed electronically to 369 individuals, of which 329 returned responses (Figure 10). VBDS completed the data collection phase in 2008 and began to compile data in preparation for analysis and a final report.

Biology, Ecology, and Control of Culex quinquefasciatus in Belowground BMPsStudies of biology, ecology, and control of Cx. quinquefasciatus mosquitoes were conducted in subterranean proprietary BMPs installed near the VBDS southern regional office in the city of Ontario. The purpose of these studies was to gather information locally that could be used to help develop effective long-term mosquito control measures for the SR-125 Project subterranean Aqua-Filters™

BMPs described previously. The objectives were to monitor mosquito egg-laying, determine factors that accelerate development of larval mosquitoes, and evaluate the potential of a structural barrier to reduce access by adult mosquitoes.

Mosquitoes were found to lay eggs in belowground BMPSs every month of the year, with greatest numbers between July and September and lowest numbers during January and February. Mosquito larvae developed more rapidly with warmer water temperatures and with increased organic content in water. The speed of larval development in water collected from BMPs was both site-dependent and variable in time, suggesting development of Cx. quinquefasciatus is more strongly influenced by watershed characteristics that determine the composition of stormwater and seasonal changes in temperature than by a particular type of BMP.

A study of simulated BMPs suggested that twice as many mosquitoes entered through vertical access points than lateral ones. In field trials, plugging vertical access points in manhole covers significantly reduced female mosquito entry and egg-laying, with greater reductions in those systems with fewer and/or more distant alternate entry points.

Education and outreachIn 2008, a strategic plan (Plan) was developed and published by VBDS to minimize the potential for mosquito breeding on state-owned properties in an effort to reduce the risk of WNV in California. The Plan was prepared under order of the Governor’s Proclamation of Emergency of August 2, 2007, which was issued in response to rapidly escalating WNV activity and the threat to public health. The Plan included specific guidelines and recommendations for Caltrans, with emphasis on minimizing mosquito production in their stormwater management infrastructure.

In 2008, VBDS continued to prepare and present reports and provide recommendations on potential public health impacts created by certain BMPs and the long-term implications associated with their construction. Four manuscripts were published in the Journal of the American Mosquito Control Association in 2008. These papers summarized findings from the 1999-2002 BMP Retrofit Pilot Study, the 2003-2006 Lake Tahoe Basin mosquito production studies, and the 2006 studies on Culex mosquito development and flight behavior through conveyance pipes. Other reports emergent from Caltrans activities are listed in VBDS Presentations and Publications beginning on page 53.


June 2009



Figure 9. Total monthly rainfall and monthly percentage of 24 structural Best Management Practices (BMPs) installed along State Route 73 (Orange County, California) with observed standing water and immature mosquitoes.




Figure 10. Approximate geographic locations of public agencies that participated in a nationwide survey on mosquito control in stormwater management structures, November 2007 – December 2008.


June 2009


U.S. Forest Service ActivitiesIn 1992, the California Department of Public Health (CDPH) Vector-Borne Disease Section (VBDS) entered into a Challenge Cost-Share Agreement with the Pacific Southwest Region (Region 5 [R5]) of the United States Department of Agriculture Forest Service (USFS) to maintain cooperative surveillance and control of vector-borne diseases within the National Forests. VBDS and USFS established this agreement to achieve mutually beneficial objectives in pest control and management, mandated by both federal and state law. VBDS and USFS R5 agreed to work cooperatively in planning and implementing vector-borne disease management programs.

In accordance with this agreement, VBDS staff in 2008 conducted field activities in and/or provided educational and safety materials to the following R5 National Forests: Angeles, Cleveland, Eldorado, Inyo, Klamath, Lake Tahoe Basin Management Unit, Lassen, Los Padres, Mendocino, Modoc, Plumas, San Bernardino, Sequoia, Shasta-Trinity, Sierra, Stanislaus, and Tahoe. VBDS personnel also visited the Humboldt-Toiyabe National Forest (USFS Intermountain Region 4) to ensure plague caution signs were posted in campgrounds and discuss vector-borne disease concerns with campground hosts. VBDS also provided consultation, certification, and oversight on vector-borne diseases and pesticide applications to autonomous agencies (environmental health departments and vector control agencies) that also interact with USFS.

Activities conducted by VBDS staff in R5 National Forests included disease surveillance, risk assessment, risk reduction, and education of USFS personnel and concessionaires. Direct surveillance included the collection and testing of indicator species and vectors for plague, hantavirus, Lyme borreliosis, and tick-borne relapsing fever (TBRF) (Table 11); indirect surveillance through visual assessment of vector-borne disease risk factors (e.g., counting active rodents and evaluating rodent burrows for abandonment) was also conducted. Based on surveillance information, VBDS offered recommendations to reduce risks of vector-borne diseases at recreational areas, fire stations, fire lookouts, employee residences, and work places. Recommendations included control of vectors, rodent management, habitat modification, and personal protection. Educational activities involved providing information on specimen collection and identification, vector-borne disease epidemiology, and methods to reduce risk of infection. VBDS staff distributed posters, brochures, and wallet cards on plague, hantavirus, Lyme disease, TBRF, tick identification, and West Nile virus to ranger district offices, USFS concessionaires, USFS fire stations, and individual campgrounds in areas endemic for these diseases. This report provides detailed information on VBDS’s activities in the individual R5 National Forests during 2008.




Table 11. Surveillance for selected vector-borne disease agents in U.S. National Forests, California, 2008.

Hantavirus Plague Plague Borrelia spp. Borrelia hermsiiNational Forest (rodents)a (rodents) (carnivores)b (Ixodes ticks) (rodents)c

Positive Tested Positive Tested Positive Tested Positive Tested Positive Tested

Angeles 0 222d 0 23 0 26 2 22

Cleveland 0 3 0 76 0 2 0 47 1 15

Eldorado 15 76 0 3 0 1Inyo 12 50 0 22 11 84

Klamath 0 21 2 30 0 21

Lake Tahoe Basin 0 5 0 3Lassen 0 15 0 3 0 6

Los Padres 0 16 1 18Mendocino 0 26 0 24 4e 201Modoc 2 3 0 24 8 36 1 19

Plumas 0 5 0 5 3 30San Bernardino 0 5 0 122 0 2 0 56 7 35

Shasta-Trinity 0 3 0 18Sierra 0 7 0 23Stanislaus 0 12 0 21Tahoe 0 3 2 21 2 25 0 25Total, all forests 29 145 2 590 16 228 4 396 22 202

a Data presented for only deer mice (Peromyscus maniculatus). All rodents tested = 410; total rodents seropositive = 31. b Carnivore specimens taken directly from or immediately adjacent to USFS lands. Because of the broad home range of some carnivores, results obtained can be inferred to a large area, including both USFS and adjacent lands.

c Columns show rodents tested for serum antibodies to Borrellia hermsii , causative agent for tick-borne relapsing fever, in collaboration with National Institutes of Health, Rocky Mountain Laboratory.

d Most testing conducted by the Los Angeles County Department of Public Health.

e Additionally, 7 Dermacentor occidentalis ticks tested by the CDC were positive for Rickettsia sp.


June 2009


VBDS ACTIVITIES IN REGION 5 NATIONAL FORESTS

Angeles National Forest

• Conducted direct TBRF surveillance at Mount Wilson Observatory in response to suspected case of TBRF. Two of 22 rodents tested by western immunoblotting (WB) were positive for Borrelia hermsii, causative agent of TBRF.

• Conducted adult and nymphal tick surveillance at Switzer Picnic Area (PA) and Shortcut Fire Station as part of a special project to validate an Ixodes risk model. Eleven adult Ixodes pacificus and two Dermacentor occidentalis were collected at Switzer PA. No ticks were found at Shortcut Fire Station. None of the nine I. pacificus tested by direct fluorescent antibody (DFA) was positive for Borrelia.

• Conducted adult and nymphal tick surveillance at Barley Flats and Red Box PAs as part of a special project to validate an Ixodes risk model. Five and 14 adult I. pacificus and one and 10 D. occidentalis were collected at the two sites, respectively. None of the 17 I. pacificus tested by DFA was positive for Borrelia.

• Conducted adult and nymphal tick surveillance at Devil’s Punchbowl as part of a special project to validate an Ixodes risk model. Five D. variabilis but no I. pacificus were collected in one hour of flagging.

• Conducted adult tick flagging at Sycamore Flat, South Fork, and Big Rock campgrounds (CG). No ticks were found in one-half hour of flagging at each location.

• Conducted direct plague surveillance of California ground squirrels (Spermophilus beecheyi) in collaboration with the Los Angeles County Department of Public Health Vector Management Program (LACDPH/VMP) at the following locations: Los Alamos CG (26 squirrels sampled), Stoneyvale PA (7), Little Rock Reservoir (26), Fishing & Hiking Hwy 39 (20), Big Tujunga Fire Station (10), Wildwood PA (7), Oak PA (14), Mt. Wilson Observatory (7), South Fork CG (27), Switzer’s PA (16), Lake Elizabeth PA (11), Upper Chilao PA (6), Jackson Lake (12), Camp Verdugo Pines (7), Camp Big Pines (6), MountainOak CG (10), Table Mountain CG (2), Ski Sunrise (2), Apple Tree CG (6). Serum antibody to Yersinia pestis, the causative agent for plague, was detected in none of the 222 squirrels tested.

• Collected blood samples from 23 carnivores on adjacent lands. Serum antibody to Y. pestis was not detected.

• Conducted indirect plague surveillance in collaboration with the LACDPH/VMP at 33 CGs, 24 PAs, 4 fire stations, the Rincon Ranger Station, and 34 other recreation areas on, leased from, or immediately adjacent to USFS lands. Follow-up direct surveillance and flea control were conducted at selected sites.

• Sent tick identification cards and hantavirus, plague, and TBRF brochures to the Forest Safety Officer.

Cleveland National Forest

• Conducted surveillance for adult and nymphal ticks at Secret Canyon Trail on two separate trips as part of a special project to validate an Ixodes risk model. Twenty-four and 35 adult I. pacificus and 6 and 28 adult D. occidentalis were collected. None of 48 I. pacificus tested positive by polymerase chain reaction (PCR) or DFA for Borrelia.



June 2009

• Conducted rodent-borne disease surveillance in collaboration with SDCDEH/VSCP at Pine ValleySCP at Pine ValleyCP at Pine Valley Trailhead, Laguna, and El Prado Group CGs, and along Old Highway 80 on USFS land. Serum antibody to Sin Nombre virus (SNV), the etiologic agent of hantavirus cardiopulmonary syndrome, was not detected in the one deer mouse (Peromyscus maniculatus) and five other microtine rodents tested.

• Conducted direct plague and TBRF surveillance at Laguna and El Prado Group CGs. Serum antibody to Y. pestis was not detected in the 15 S. beecheyi tested. One of 15 samples was positive by WB for antibody to B. hermsii.

• Conducted direct plague surveillance in collaboration with SDCDEH/VSCP at Burnt Rancheria,SCP at Burnt Rancheria,CP at Burnt Rancheria, Observatory, Horse Heaven, Laguna, El Prado Group, Oak Grove, and Cibbets Flat CGs. Serum antibodies to Y. pestis were detected in none of the 61 S. beecheyi tested.

• Collected blood samples from two carnivores on adjacent lands. Serum antibody to Y. pestis was not detected.

• Conducted rodent-borne disease surveillance in collaboration with Riverside County Department of Environmental Health Vector Control Program (RCDEHVCP) on and adjacent to USFS lands. Serum antibody to SNV was not detected in the 29 samples tested.

• Developed a S. beecheyi control options plan for plague risk reduction in an ecologically sensitive area at the request of the Recreation Officer of the Descanso Ranger District. The plan minimizes the risk of fleas seeking alternative hosts in this potentially plague-endemic area.

Eldorado National Forest

• Continued a multi-year rodent-borne disease surveillance project monitoring long-term trends in rodent population dynamics and SNV transmission at Leek Springs Lookout and Lumberyard Fire Station in June, August, and October. Three nights of trapping (450 trap-nights) conducted in 2008 yielded 79 rodents: 76 P. maniculatus, 2 Microtus longicaudus, and one P. boylii. Seroprevalences of antibodies to SNV in P. maniculatus were 25, 20, and 17 percent at the fire station and 21, 20, and 9 percent at the lookout in June, August, and October, respectively. Although recent habitat modification (tree and brush clearing) at had significantly reduced mouse abundance and activity at the fire station, the overall seroprevalence remained higher (23%) than at the lookout (18%).

• Visited Amador Ranger Station and met with Recreation Officer. Updated contact lists, discussed available resources, and provided vector-borne disease education materials.

• Conducted indirect plague surveillance at most campgrounds, day-use, and trail heads, including kiosk along the lower portion of Mormon Emigrant Trail, Mokelumne, White Azalea Campgrounds, Kirkwood Lakes, Martin Meadows, Silver Lakes area, and boat launch of Salt Springs Reservoir.

• Conducted visual assessments of rodent activity at Damsite, Middle Creek, and Lower Blue Lake CGs operated by Pacific Gas and Electric Company. Plague and hantavirus public information brochures were provided to campground hosts and plague caution signs were posted.

• Tested for plague a black bear from adjacent land; serum antibody to Y. pestis was not detected

Inyo National Forest

• Investigated four known or suspected cases of TBRF on lands immediately adjacent to, owned by, or leased-out by USFS at Crooked Creek Station, Lake Sabrina, Pine Glade, and Swall Meadows.


June 2009


Serum antibody to B. hermsii was detected by WB in 4 of 18 (22%), 1 of 8 (13%), 0 of 8, and 1 of 3 (33%) rodents collected at the four sites, respectively.

• Continued a multi-year project on rodent-borne disease risk at Lee Vining Ranger Station. Six trapping events totaling 600 trap-nights yielded 50 sera from P. maniculatus. Serum antibodies toSerum antibodies to to SNV were detected in 12 sera (24% seroprevalence). However, the overall abundance of deer mice was well below (~80%) historic levels at this location.

• Surveillance for TBRF at Lee Vining Ranger Station detected serum antibody to B. hermsii in 2 of 27 (7%) non-microtine rodents opportunistically sampled.

• Conducted direct plague and TBRF surveillance at Four Jeffrey CG. Serum antibody to Y. pestis was detected in none of 25 rodent sera. Serum antibodies to B. hermsii were found in 3 of 20 (15%) rodents submitted.

• Tested (negative) one belding ground squirrel carcass from Sabrina CG for Y. pestis.

• Conducted indirect plague surveillance at Four Jeffrey, Forks, Willow, and Table Mountain Group CGs. Sciurid rodent abundance was estimated to be high at Four Jeffrey but low at the other three CGs.

• Conducted indirect plague surveillance at New Shady Rest, Old Shady Rest, and Sherwin Creek CGs. All CGs exhibited average to low levels of sciurid rodent activity.

• Conducted indirect plague surveillance at Saddlebag Lake, Junction, and Ellery Lake CGs. Sciurid rodent abundance was estimated to be average to low at each location.

• Conducted indirect plague surveillance at Grandview CG. Sciurid rodent abundance was estimated to be average.

• Presented disease prevention talk to approximately 300 employees and concessionaires at the Inyo NF All Employee Meeting in Mammoth Lakes. Distributed tick cards and brochures on vector-borne diseases commonly found on the Inyo NF to attendees.

• Met with the Forest Supervisor and discussed the comparatively high risk of hantavirus in the eastern Sierra.

• Distributed vector-borne disease informational brochures to the White Mountain Ranger District and discussed vector-borne diseases with personnel present.

Klamath National Forest

• Conducted direct rodent-borne disease surveillance at Juanita Lake Campground. Forty traps yielded 21 rodents (P. maniculatus, Neotoma fuscipes, S. lateralis, and Tamias senex). Serum antibodies toY. pestis and B. hermsii were found in none of the 21 rodents tested. Serum antibody to SNV was not detected in the two P. maniculatus tested.

• Collected blood samples from carnivores on adjacent lands. Serum antibodies to Y. pestis were detected in two of 30 carnivores tested.

• Conducted indirect rodent surveillance at Shafter and Martin’s Dairy CGs; rodent abundance was considered low at both locations.

• Visited Klamath Supervisor’s Office and met with the new forest Safety Officer. Updated contact lists and provided staff with educational materials.



June 2009

• Provided staff at Goosenest Ranger District and Work Station with vector-borne disease educational brochures.

Lake Tahoe Basin Management Unit

• Conducted a site inspection of a USFS employee’s residence for the presence of Ornithodoros hermsi ticks at the Tallac Historic Site after an engorged O. hermsi tick was recovered by USFS personnel. An additional O. hermsi tick was recovered from the employee residence. Neither tick was positive for B. hermsii spirochetes.

• Tested five rodent carcasses for presence of Y. pestis; all were negative.

• Collected blood samples from three carnivores on adjacent lands. Serum antibody to Y. pestis was not detected.

• Conducted indirect plague surveillance at the following CGs and facilities: Bayview, Camp Richardson Resort, Fallen Leaf, Kaspian, Meeks Bay, William Kent, and the Tallac Visitor Center. The Tallac Visitor Center and Fallen Leaf CG showed high densities of sciurid rodents.

• Discussed vector-borne disease issues with the Safety Officer and provided specific recommendations concerning TBRF risk reduction.

Lassen National Forest

• Conducted direct disease surveillance for plague and TBRF at Lake Almanor CG. Serum antibodies to Y. pestis or B. hermsii were not detected in 15 rodents tested.


• Conducted a visual inspection of the Almanor Ranger District main facilities for areas needing rodent proofing improvements.

• Discussed available resources with Hat Creek Ranger District and Almanor Ranger District personnel. Distributed vector-borne disease educational brochures and updated contact lists.

Los Padres National Forest

• Conducted direct plague surveillance at Chuchupate CG. Serum antibody to Y. pestis was detected in none of 16 rodents tested.

• Collected blood samples from carnivores on adjacent lands. Serum antibody to Y. pestis was detected in one of 18 carnivores tested.

• Conducted indirect plague surveillance at the following campgrounds: Fremont, Paradise, Los Prietos, Upper Oso, Sage Hill Group; and day use areas: Whiterock, Lower Oso, Falls, and First Crossing. Sciurid rodents were abundant at Upper Oso, Sage Hill Group, and Paradise CGs; all other locations had few or no sciruid rodents present.

• Conducted indirect plague surveillance at Mt. Pinos, McGill, Caballo, Marion, and Toad Springs CGs. S. beecheyi numbers were estimated to be low at all locations. Very few chipmunks were seen at McGill and Mt. Pinos CGs.


June 2009


Mendocino National Forest

• Conducted adult and nymphal tick surveillance at Sunset CG. One hundred twenty adult male, 90 adult female, and 11 nymphal I. pacificus were collected. Eleven D. occidentalis were also collected. Four of the 20 I. pacificus pools tested were positive by PCR for Borrelia sp. Seven of 11 D. occidentalis tested positive for Spotted Fever group Rickettsia.

• Conducted direct plague surveillance at Middle Creek CG. Serum antibody to Y. pestis was detected in none of 26 S. beecheyi tested.


Modoc National Forest

• Performed direct rodent-borne disease surveillance at Blue Lake CG. Serum antibodies to Y. pestis and B. hermsii were detected in none and 1 of 17 samples, respectively. Serum antibody to SNV was detected in one of 2 P. maniculatus.

• Performed rodent-borne disease surveillance at Medicine Lake- Hemlock and Headquarters CGs. Serum antibody to SNV was found in the single P. maniculatus trapped in Hemlock CG. Antibody to Y. pestis was not detected in eight rodent sera submitted for testing. Serum antibody for B. hermsii was found in neither of two samples tested.

• Collected blood samples from carnivores on adjacent lands. Serum antibodies to Y. pestis were detected in eight of 36 carnivores tested.

• Conducted indirect plague surveillance at Patterson, Mill Creek Falls, and Soup Spring CGs. Few sciurid rodents were observed and the risk for plague was estimated to be low at all locations.

• Visited Modoc Supervisor’s Office and Big Valley Ranger District and met with Recreation Officer. Updated contact lists, discussed available resources, and provided vector-borne disease education materials.

• Provided campground hosts with vector-borne disease education brochures and materials.

Plumas National Forest

• Continued a rodent-borne disease project employing mark-recapture methods. Two hundred sixteen rodents were captured at the Laufman Fire Station during four surveillance events (2 nights trapping per surveillance event) conducted in April, June, August, and October. Serum antibody to SNV was detected in none of 5 P. maniculatus and one of 140 P. boylii samples. Serum antibody to Y. pestis was not detected in five S. beecheyi tested opportunistically.

• Discussed safety training for USFS staff with the Province Safety Officer.

San Bernardino National Forest

• Conducted TBRF surveillance at Holcomb, San Gorgonio, Fern Basin, and Marion Mountain CGs. Serum antibodies to B. hermsii were detected in seven of 14, none of 10, none of 4, and none of 7 sciurid rodents tested from each site, respectively.



June 2009

• Conducted surveillance for adult and nymphal I. pacificus along Black Mountain Trail as part of a special project to validate an Ixodes risk model. One adult I. pacificus and six D. occidentalis were collected. The I. pacificus was negative by DFA for Borrelia sp.

• Conducted surveillance for adult and nymphal ticks at Kenworthy Fire Station on two separate occasions as part of a special project to validate an Ixodes risk model. One nymphal I. pacificus, 54 adult I. pacificus, and 19 D. occidentalis were collected. None of 49 I. pacificus adults nor a single nymph tested was positive for Borrelia sp. by DFA.

• Conducted surveillance for adult and nymphal I. pacificus at Bonilla Springs on two occasions as part of a special project to validate an Ixodes risk model. A total of 5 person-hours of flagging yielded no ticks.

• Conducted surveillance for adult ticks at Mill Creek Ranger station and Mountain Home Creek Rest Area. Thirty-nine D. occidentalis and six I. pacificus ticks were collected. None of the six I. pacificus ticks tested were positive by PCR forere positive by PCR for positive by PCR for Borrelia sp.

• Conducted surveillance for adult ticks along the Momyer Trail. Fourteen adult D. variabilis were collected.

• In collaboration with the San Bernardino County Vector Control Program (SBCVCP), 144 adult I. pacificus were collected from various locations throughout the forest.

• In collaboration with the Riverside County Department of Environmental Health Vector Control Program (RCDEHVCP), 30 adult I. pacificus were collected from Thomas Mountain.

• In collaboration with the Coachella Valley Mosquito and Vector Control District conducted rodent-borne disease surveillance at Kenworthy Fire Station. Serum antibody to SNV was not detected in the two mice tested.

• Conducted rodent-borne disease surveillance in collaboration with the SBCVCP at various locations on the forest. Serum antibody to SNV was detected in none of the 17 rodents tested.

• Conducted direct plague surveillance in collaboration with SBCVCP, at Lobo-Oso Group, San Gorgonio, Heartbar, Crab Flats, and Barton Flats CGs. Serum antibody to Y. pestis was detected in none of 5, 16, 38, 18, and 12 rodents from each site, respectively.

• Conducted direct plague surveillance in collaboration with the RCDEHVCP at the Fern Basin, Marion Mountain, and Dark Canyon CGs on the San Jacinto Ranger District. Serum antibody to Y. pestis was detected in none of 5, 16, and 12 samples from each site, respectively.

• Collected blood samples from carnivores on adjacent lands. Serum antibody to Y. pestis was detected in neither of the two carnivores tested.

• Conducted indirect plague surveillance at Marion Mountain and Fern Basin CGs. Sciurid numbers were estimated to be average with approximately 7-10 rodents seen per campground.

• Conducted rodent-borne disease surveillance in collaboration with RCDEHVCP on and adjacent to USFS lands. Serum antibody to SNV was not detected in 4 deer mice and 16 other microtine rodents tested.

• Conducted indirect plague surveillance at Thomas Mountain and Tool Box Springs CGs for rodentCGs for rodent for rodent activity. No rodents were seen during the surveillance event.. No rodents were seen during the surveillance event.

• Inspected Kenworthy Fire Station facility structures for evidence of and opportunity for rodent access. Provided vector-borne disease education material to USFS personnel.


June 2009


• Delivered tick identification cards, and information brochures for hantavirus, plague, and TBRF to the San Bernardino NF Headquarters.

Sequoia National Forest

• Conducted indirect plague surveillance at Fish Creek CG. Sciurid rodent numbers were estimated to be average.

Shasta-Trinity National Forest

• Conducted tick surveillance at Bailey Cove CG. Flagged 24 male I. pacificus, 18 female I. pacificus, and 3 D. occidentalis. Borrelia sp was detected in none of the 18 female I. pacificus tested by PCR.

• Conducted tick surveillance along a paved, wheelchair-accessible trail at Pollard Gulch CG. Forty male I. pacificus, 53 female I. pacificus, and 1 D. occidentalis were collected.

• Conducted tick surveillance at Moore CG. Thirty male I. pacificus, 33 female I. pacificus, and 1 D. occidentalis were collected.

• Conducted tick surveillance at Nelson Point CG. Nine male I. pacificus, 22 female I. pacificus, and 1 D. occidentalis were collected.

• Conducted tick surveillance at McCloud Bridge CG/Roadcut. Eighty-three male I. pacificus and 90 female I. pacificus were collected.

• Conducted tick surveillance at Mary Smith CG. Nineteen male I. pacificus and 18 female I. pacificus were collected.

• Conducted tick surveillance at Cooper Gulch CG. Thirty-three male I. pacificus and 37 female I. pacificus were collected.


• Conducted indirect plague surveillance at East Weaver, Rush Creek, and Bridge Camp CGs. No sciurid rodent activity was observed.

• Evaluated implementation of recommendations from 2007 on rodent control in and around facilities at McCloud Ranger District. Verified that USFS staff were actively trapping and safely disposing of nuisance rodents. VBDS personnel advised continuing the program and provided more vector-borne disease educational materials.

• Performed a walk-through of facilities to assess the progress made on rodent exclusion at Ash Creek Fire Station. Most VBDS recommendations made in 2007 had been implemented. VBDS biologists made further recommendations and provided the staff with additional vector-borne disease educational materials.

• Visited Trinity River CG and provided the host with vector-borne disease education brochures.



June 2009

Sierra National Forest

• Conducted adult and nymphal tick surveillance along Lewis Creek National Trail and an ATV trail in the Chepo Saddle area. No ticks were found at Lewis Creek; two adult and one nymphal I. pacificus ticks were collected from the Chepo Saddle ATV trail. All ticks were negative by PCR for Borrelia sp.

• Conducted surveillance for adult and nymphal ticks along Savage Lundy Trail. Twenty I. pacificus were collected and tested negative by PCR for Borrelia sp.

• Collected blood samples from seven carnivores on adjacent lands. Serum antibody to Y. pestis was not detected.

• Performed indirect plague surveillance at Crane Valley Group Camp (GC), Recreational Point PA and GC, Denver Church PA, Little Denver Church PA, Rocky Point PA, Forks CG, Lupine-Cedar Bluff CG, Spring Cove CG, and Wishon Point CG. Sciurid rodent abundance was estimated to be low at all sites except Recreational Point PA and Forks CG where averageal Point PA and Forks CG where average Point PA and Forks CG where average S. beecheyi abundance was observed. Each campground had a host, but plague caution signs were often absent.as observed. Each campground had a host, but plague caution signs were often absent. observed. Each campground had a host, but plague caution signs were often absent. Lakeside, Pine Point, and Pine Slope PAs were under construction and inaccessible.

• Delivered plague, hantavirus, Lyme disease, TBRF brochures and tick identification cards to the Bass Lake Ranger Station. Discussed the Cost-Share agreement and VBDS program with district personnel.

• Provide 300 tick identification cards to Safety Officer.

Six Rivers National Forest

• No activities in 2008

Stanislaus National Forest

• Conducted direct plague surveillance at Camp Wolfeboro as a follow-up to an earlier visit. Serum antibody to Y. pestis was detected in none of 12 rodents tested.


• Conducted indirect plague surveillance and evaluated mosquito activity at Highland Lakes, Pacific Valley, Hermit Valley, Mosquito Lake, and Lake Alpine CGs. Distributed plague and hantavirus brochures and plague caution posters to rangers and campground hosts. Posted plague caution posters at most campgrounds, day-use areas, and trail heads.

• Conducted indirect surveillance for rodent activity and inspected buildings for signs of rodent infestation at the Boy Scouts of America’s Camp Wolfeboro. Discussed needed improvements and problem areas with camp directors and property manager and emphasized proper hantavirus preventive measures.

• Posted plague caution signs at Cottage Springs PA, Sand Flat CG, Sour Grass Recreational Area, Boards Crossing, Stanislaus River, and Spicer Reservoir Group CGs and boat launch.

• Provided brochures on Lyme disease, hantavirus, and plague, tick identification cards, and plague caution signs to hosts at Sour Grass and Big Meadow CGs.


June 2009


• Distributed rodent and other vector-borne disease prevention literature to the station engineer at Dorrington/Ebbets Pass Fire and Information Station.

• Presented safety information on hantavirus, plague, Lyme disease, and TBRF to approximately 75 staff members at the Boy Scouts of America’s Camp Wolfeboro. Distributed approximately 225 tick identification cards, tick-borne disease, plague, and hantavirus brochures.

• Met with the fire training and Safety Officer, discussed training opportunities and obtained contact information for ranger districts.

Tahoe National Forest

• Investigated two cases of TBRF in residences immediately adjacent to USFS land. Serum antibody to B. hermsii was detected in one of nine total rodents tested from both sites. Serum antibody to Y. pestis was detected in none of 13 rodents tested.

• Conducted surveillance for adult and nymphal ticks at the Forest Headquarters. Seventeen adult and 7 nymphal I. pacificus, 10 adult D. occidentalis, and one adult D. variabilis were collected. None of the 24 I. pacificus tested positive by PCR for Borrelia sp.

• Conducted adult and nymphal tick surveillance at White Cloud CG. Two adult and one nymphal I. pacificus ticks were collected. The nymphal tick tested negative by PCR for Borrelia sp.

• Conducted rodent-borne disease surveillance at Sardine Fire Lookout in response to a USFS request for a hantavirus risk analysis of the lookout prior to planned cleanup by USFS personnel. Serum antibody to SNV was detected in none of the three deer mice captured. Serum antibodies to mice captured. Serum antibodies tomice captured. Serum antibodies to Y. pestis were detected in two of five chipmunks sampled, with titers of 1:64 in both animals. VBDS notified the Safety Officer of the surveillance results and provided a brief set of recommendations.

• Tested three rodent carcasses from private lands adjacent to USFS land for plague; Y. pestis was not detected.

• Collected blood samples from carnivores on adjacent lands. Serum antibodies to Y. pestis were detected in 2 of 25 carnivores tested.

• Conducted indirect surveillance for plague and posted plague caution signs at the following campgrounds and recreational areas: Lakeside, Boca Springs, Boca Rest, Boca, Prosser, Lower Little Truckee, Upper Little Truckee, Boyington Mill, Cold Creek, Cottonwood and Logger. No evidence of plague activity was observed at any of the campgrounds evaluated. Boca, Prosser and Logger have significant numbers of sciurid rodents.

• Provided brochures and plague warning signs to USFS personnel at Truckee Ranger Station.

Humboldt-Toiyabe National Forest

• Distributed plague and hantavirus brochures and plague caution posters to campground hosts. Plague caution signs were posted at most CGs, day-use areas, and trail heads, including Evergreen, Damsite, Middle Creek and Lower Blue Lake CGs, and Tamarack Junction.

• Conducted indirect plague surveillance at the following campgrounds and day-use areas: Kit Carson, Tamarack Junction, Crystal Springs, Markleeville, Wolf Creek, and Silver Creek. Plague, TBRF, and hantavirus brochures were provided to all campground hosts and plague caution signs were posted.



June 2009

SPECIAL PROjECT: Field Validation of a Spatial Risk Model for Nymphal Tick Exposure and Lyme Disease in Southern California National Forests

In August 2007, staff of VBDS and the CDPH California Epidemiologic Investigation Service program initiated a project to field validate a previously published spatial risk model for I. pacificus nymphs in California. Because little information is available on the ecology and distribution of I. pacificus nymphs in southern California, sites in southern California National Forests which the model identified as “high risk” were selected for study during the first year of the project. Sites for surveillance for adult and nymphal I. pacificus were selected in Cleveland, San Bernardino, and Angeles National Forests. The objectives of the project were to verify the presence of I. pacificus nymphs in predicted areas, to estimate peak seasonality for nymphal abundance at these sites, and to determine prevalence of B. burgdorferi infection in ticks collected from these sites. It was anticipated that results from this project would enhance knowledge of the ecology of I. pacificus ticks and Lyme disease risk in southern California National Forests and aid in development of appropriate disease prevention strategies for visitors and USFS staff.

Other services provided

• Sent a pre-season letter to R5 Safety Officer for distribution to all USFS R5 Supervisors, District Rangers, and campground concessionaires. This letter described the services VBDS staff can provide to the USFS and included contact information for VBDS biologists.

• Sent 300 tick identification cards for distribution to R5 Headquarters.

• Provided R5 Safety Officer with West Nile virus updates on positive findings on or near USFS lands.

• Presented “Vector-Borne Diseases in USFS Region 5, An Update for Safety Officers” at the USFS Safety Workshop in Pacific Grove.

• Presented a summary of 2007 USFS activities and short and long-term goals to the Vector Control Advisory Committee in Sacramento.

• Developed and initiated beta-testing of an Access database to document all VBDS activities ondocument all VBDS activities on all VBDS activities on USFS lands.

• Initiated flea identification training to enhance the USFS rodent-borne disease processing capabilities.

• Published a flea control study conducted on USFS lands at Los Padres National Forest.

• Provided R5 Safety Officer a semi-annual update of USFS activities conducted by VBDS personnel.


June 2009


National Park Service Activities

In September 2007, the National Park Service (NPS) signed a cooperative agreement with the California Department of Public Health (CDPH) to develop a vector-borne disease prevention program for the 24 NPS units in California. The NPS Office of Public Health (OPH) provided funding for a three-year pilot program to support the CDPH Vector-Borne Disease Section (VBDS) to conduct surveillance, perform site evaluations, and provide expert consultation to help reduce the risk of vector-borne diseases to visitors and staff.

This report summarizes activities pursuant to this cooperative agreement that VBDS conducted in 2008.

Golden Gate National Recreation Area

In September 2008, VBDS staff conducted rodent surveillance for Sin Nombre virus (SNV), the viral agent of hantavirus cardiopulmonary syndrome (HCPS), on Alcatraz Island in the Golden Gate National Recreation Area (GOGA). Overnight live-trapping was conducted in both interior and exterior areas that visitors and/or NPS staff frequently visited, including cell blocks and maintenance areas. A total of 13 deer mice (Peromyscus maniculatus) were collected—two from inside the cell blocks and 11 from outside. Serum antibodies to SNV were detected in none of the rodents. VBDS provided recommendations to GOGA staff on minimizing opportunity for rodent ingress and infestation of buildings and facilities.

Golden Gate National Recreation Area and Point Reyes National Seashore

Between January and June, 2008, VBDS staff conducted tick surveillance in and around hiking and walking trails in Golden Gate National Recreation Area (GOGA) and Point Reyes National Seashore (PORE). At least 0.5 person-hours of flagging were conducted approximately monthly at each of three sites each in GOGA and PORE. A total of 271 ticks was collected from five of the six surveillance sites: 104 western black-legged ticks (Ixodes pacificus), 144 Pacific Coast ticks (Dermacentor occidentalis), and 23 American dog ticks (Dermacentor variabilis). Borrelia bacteria were detected by direct fluorescent antibody in 3 of 69 adult I. pacificus and 0 of 3 nymphal I. pacificus. The three positive ticks were collected from the Fort Baker area. VBDS recommended continued trailside vegetation maintenance and posting of Tick Warning signs at trailheads to reduce risk of tick bite for visitors and staff.

Lassen Volcanic National Park

In August 2008, VBDS staff conducted surveillance of rodents for Borrelia hermsi, SNV, and Yersinia pestis, the agents of tick-borne relapsing fever (TBRF), HCPS, and plague, respectively, at Lassen Volcanic National Park (LAVO). A total of 252 rodent trap-nights were conducted in the campground, residential area, and maintenance yard near Manzanita Lake. Serum antibodies to Y. pestis were detected in none of 17 golden-mantled ground squirrels (Spermophilus lateralis) and 5 shadow chipmunks (Neotamias senex) captured. Serum antibodies to B. hermsii were detected in 1 of 10 S. lateralis and 0 of 5 N. senex tested. Eight P. maniculatus were captured; antibodies to SNV were detected in serum from one deer mouse collected from the campground area. VBDS staff inspected select residences and maintenance buildings for signs of rodent infestation and conveyed observations and recommendations for rodent exclusion and control to LAVO staff.



June 2009

Lava Beds National Monument

In April 2008, VBDS staff conducted rodent surveillance in caves within Lava Beds National Monument (LABE) that had high visitor use or in which evidence of plague had been previously observed. Trap success was low and three woodrats (Neotoma sp.) and 29 Peromyscus spp. tested for serum antibody to Y. pestis were negative.

VBDS staff returned to LABE in September to conduct rodent surveillance on the surface, in and around the residential and maintenance compounds, campground loops, and trails, as well as in the caves. Six bushy-tailed wood rats (Neotoma cinerea) and six canyon mice (Peromyscus crinitus) were captured from the caves; all were negative for antibodies to Y. pestis and SNV. A total of 23 rodents were captured on the surface; all were negative for antibodies to Y. pestis, but antibodies to SNV were detected in one of seven P. maniculatus and one of seven P. truei. Both seropositive mice were collected from the residential compound. VBDS staff conducted training of LABE staff to promote rodent-borne disease awareness and the identification of potential exposure risks and appropriate mitigation measures.

Manzanar National Historic Site

In July 2008, VBDS staff conducted a visual assessment of the main facility building at Manzanar National Historic Site (MANZ). Little evidence of rodent infestation or opportunity for rodent ingress were observed. VBDS staff returned in September to conduct rodent surveillance to evaluate risk of hantavirus exposure. Forty-one live traps were set within and around the main facility and an outbuilding. One P. maniculatus was captured outside the main facility, and one desert woodrat (Neotoma lepida) was captured near the outbuilding. Thirty additional live traps set in the historic orchard area yielded seven N. lepida, four desert mice (Peromyscus eremicus), and two California ground squirrels. Serum antibodies to SNV and B. hermsi were detected in none of the rodents tested. VBDS recommended that MANZ staff maintain cleared buffer zones around buildings and cleanliness within buildings to reduce incentives for rodent ingress.

Whiskeytown National Recreation Area

In June 2008, VBDS staff attended an employee training day at Whiskeytown National Recreation Area (WHIS) and led discussions on the ecology of vector-borne diseases, safety and employee awareness and responsibility issues, and past vector-borne disease problems at WHIS. WHIS staff were provided CDPH vector-borne disease prevention materials.

Yosemite National Park

In September 2008, VBDS conducted rodent surveillance for B. hermsi, Y. pestis, and SNV at Tuolumne Meadows; this work was followup to a TBRF case investigation that VBDS conducted in Yosemite National Park (YOSE) in September 2007. Daytime and overnight live rodent trapping were conducted in and around staff buildings and residences. Two of seven (29%) lodgepole chipmunks (Tamias speciosus) and one of four (25%) golden-mantled ground squirrels (S. lateralis) tested positive for antibodies to B. hermsi. Three chipmunk and squirrel sera were tested for antibodies to Y. pestis; all were negative. Twenty-two deer mice (P. maniculatus) were collected, 11 from inside buildings. Serum antibodies to SNV were detected in 5 of 21 (24%) deer mice tested.

The exteriors of several buildings at the Ranger Station were visually assessed for rodent entry potential. Carbon dioxide tick traps were placed in or near rodent nests found in buildings to attempt to collect “soft” ticks (Ornithodoros sp.). In addition, rodent nesting materials that were removed from


June 2009


building interiors were examined for soft ticks. No soft ticks were collected from tick traps nor recovered from rodent nests.

In addition to activities at Tuolumne Meadows, VBDS personnel visually inspected a residence in Foresta for the presence of rodents and Ornithodoros tick infestation, following reports of a suspected case of TBRF in a recent resident. No ticks and minimal evidence of rodent activity were observed. VBDS staff advised the current residents of rodent control and TBRF preventive measures.

Finally, VBDS staff led seminars on TBRF, HCPS, and other vector-borne diseases for YOSE staff and concessionaires in Curry Village.



June 2009

Other Vectors and Public Health PestsAfricanized honey beesAlmost 40 years after their introduction to Brazil and subsequent expansion into South, Central, and North Americas, Africanized honey bees (Apis mellifera scutellata; AHB) entered California in 1994. Through 2008, the California Department of Food and Agriculture reported that AHB had spread throughout southern California south of the Tehachapi Mountains, especially the desert regions of Imperial, Riverside, and San Bernardino counties. North of the Tehachapi Range, AHB has been detected in Inyo, Kern, and Tulare counties and as far north as Madera County. Along the southern coast, isolated AHB detections have occurred as far north as San Luis Obispo County. Occasional human and domestic pet stinging incidents continue to be locally reported from southern California, including the deaths of two Imperial County residents in 2008. Continued public education efforts at the local level remind residents as well as first responders of the potential hazards that feral honey bee colonies present.

Red imported fire antsVBDS continued to serve as liaison with CDFA, county agriculture departments, and local vector control agencies that conduct eradication programs for red imported fire ants (RIFA). The CDFA reported that over 16,500 acres of chiefly agricultural land in Fresno, Kern, Madera, Merced, San Joaquin, and Stanislaus counties were treated for RIFA infestation. In southern California, CDFA continued to monitor limited RIFA in San Bernardino, western Riverside, and San Diego counties. Eradication of the RIFA infestation in San Diego County is ongoing.

The Coachella Valley Mosquito and Vector Control District (CVMVCD) reported that over 20,000 acres were treated for RIFA infestations within their district in 2008. Treatments were conducted in 14 communities on residential, country club, and golf course sites. Sixty-seven square miles remain under CDFA RIFA quarantine guidelines in Riverside County. The Orange County Vector Control District Fire Ant Program conducted or contracted-out over 2900 treatments on infested properties. All of Orange County (790 square miles) remains under RIFA quarantine. The Los Angeles County Agricultural Commissioner and Weights and Measures Department RIFA Eradication Program treated 930 properties in 16 communities in 2008. Surveys identified 763 RIFA-infested properties in 22 Los Angeles County communities. RIFA quarantine remains in effect for 8.5 square miles of the county.

ScorpionsIn 2007-08 VBDS collaborated with the San Gabriel Valley Mosquito and Vector Control District and the Los Angeles County Department of Public Health to investigate reports of a scorpion infestation in a suburban neighborhood of Los Angeles County. Infestations of the Arizona bark scorpion (Centruroides exilicauda) were confirmed at three properties where residents reported having encountered scorpions both indoors and outdoors. C. exilicauda is the only medically important scorpion in the United States and produces a sting that is painful but rarely fatal. It is endemic throughout Arizona and in California along the Colorado River corridor, but may be incidentally transported to distant locals in vehicles, as is suspected in this case. A program of scorpion removal, exclusion from indoor spaces, and habitat modification was implemented by residents of the three infested properties. Scorpion management fact sheets and guidelines were provided to neighborhood residents to help ensure eradication from the neighborhood. While residents continued to encounter scorpions outdoors in 2008, these were less frequent than in previous years.

Lice, bed bugs, and scabiesVBDS continued a program initiated in 2007 to educate urban homeless clients and their providers about public health pests. In cooperation with Project Homeless Connect, VBDS offered head


June 2009


(Pediculus humanus), body, and pubic (Pthirus pubis) louse checks, plus bed bug (Cimex lectularius) and scabies (Sarcoptes scabiei) consultations at Project Homeless events in San Francisco, Los Angeles, and San Jose. In San Francisco, over 132 clients received consultations. Of these, 27 clients had body lice infestations (628 lice collected), eight had head lice infestations (11 lice collected), 12 reported bed bug bites, and two had scabies. Clients found infested with lice and/or scabies received free insecticidal lotions provided through the pharmacy division. Clients were able to exchange their infested clothing for clothing donated by CDPH staff and San Francisco businesses. In Los Angeles, 73 clients visited the CDPH booth; 19 body lice were collected off clothing received from six clients. In addition, staff distributed educational materials and took 21 bed bug reports. No infestations were identified at the San Jose event.

Collected lice were sent to the Centers for Disease Control and Prevention, Fort Collins, Colorado, as part of a collaborative project on Bartonella quintana (the agent of trench fever) among the homeless. B. quintana was identified in lice from two of the San Francisco clients in 2008. A survey of possible risk factors for body lice infestations in San Francisco homeless people was initiated in December 2008 and will continue until December 2010.



June 2009

Vector Control Technician Certification ProgramThe California Department of Public Health (CDPH) administers the Public Health Vector Control Technician certification examination in May and November each year. The purpose of this examination is to certify the competence of government agency personnel to handle and apply pesticides for public health purposes. Authority to administer this exam derives from the Health and Safety Code, Section 106925, which requires every government agency employee who handles, applies, or supervises the use of any pesticide for public health purposes to be certified by CDPH. CDPH first sponsored certification examination of agency personnel on mosquito control in April 1974. Standards governing certification of local agency vector control personnel are described in Title 17 of the California Code of Regulations, Sections 30001-30061. To become certified in a control category, applicants must pass the Core section and at least one Specialty section of the examination. Each applicant to the examination pays a fee for each section requested on the application. The Core section consists of questions about the safe and effective use of pesticides. Specialty sections of the examination include the Biology and Control of Mosquitoes in California, Arthropods of Public Health Significance in California, and Vertebrates of Public Health Importance in California (Table 12). Successful examinees are issued a gold certification card that is valid for two years in the qualified categories specified on the card. To maintain full certification status in subsequent two-year cycles, Certified Technicians must pay annual renewal fees and fulfill minimum continuing education requirements. Successful examinees who elect not to participate in continuing education are issued parchment certificates in the categories in which they qualified. These Certified Technicians (Limited) employees may use pesticides only under the direct supervision of a Certified Technician.

Through 2008, 1269 Vector Control Technicians employed at 115 local public health agencies and CDPH held 2851 certificates (Table 13). The agencies include 54 mosquito abatement districts, mosquito and/or vector control districts and other special districts, 44 departments of county government, 16 departments of city government, and CDPH. Table 14 compares the certification status among employees of Mosquito and Vector Control Association of California (MVCAC) corporate member agencies and non-MVCAC member agencies.

In 2008, CDPH revised the training manuals for the Core and Biology and Control of Mosquitoes sections. These training manuals, as well as practice questions and the Continuing Education Guide, were posted on a newly created website dedicated to the Vector Control Technician Program:http://www.cdph.ca.gov/certlic/occupations/Pages/VectorControlTechnicianProgram.aspx


June 2009



Table 13. Public Health Vector Control Technician certificates in effect as of December 2008.

Table 12. Results of Public Health Vector Control Technician certification examinations administered in 2008.

Table 14. Certified Public Health Vector Control Technicians employed by Mosquito and Vector Control Association of California (MVCAC) corporate member agencies and non-MVCAC agencies.

Exam section No. exams given No. passed (%)Core 132 114 (86%)Mosquito Control 143 118 (83%)Terrestrial Invertebrate Control 134 77 (57%)Vertebrate Vector Control 104 77 (74%)

Totals 506 386 (76%)

No. certificatesCertification category Full status Limited status TotalMosquito Control 810 254 1064Terrestrial Invertebrate Vector Control 616 212 828Vertebrate Vector Control 627 332 959

Totals 2053 798 2851

Certified Technicians Certified Technicians (Limited)Agency type No. agencies No. employees No. agencies No. employeesMVCAC 60 728 17 149Non-MVCAC 20 97 38 295

Totals 80 825 55 444



June 2009

Presentations and PublicationsVector-Borne Disease Section Staff

Oral Presentations

Vector-borne diseases, general• Vector-borne disease ecology and awareness Peter Bonkrude, Larry Bronson: National Park Service (NPS) staff training, Whiskeytown National Recreation Area

• Vector-borne diseases of concern to BLM employees in California Joseph Burns: Bureau of Land Management Bishop Field Office, Bishop

• Vector-borne diseases of the eastern Sierra Joseph Burns: Inyo National Forest All Employee meeting, Mammoth Lakes

• Things that buzz, squeak, bite, and suck: The hapless life of a vector-borne disease epidemiologist Curtis Fritz:Topics in Public Health Seminar (EPP 298-012), University of California, Davis.

• Surveillance of vector-borne diseases in California Anne Kjemtrup o Arthropod-Borne Zoonotic Diseases: Basic Principles and Methods of Study (ESPM 145),

University of California, Berkeley o Principles of Epidemiology (EPM 405), University of California, Davis

• Vector-borne diseases in California: an update Vicki Kramer: State Public Health Vector Control Conference, Fort Collins, Colorado

• Protecting yourself from vector-borne diseases Marco Metzger: 17th Annual Urban Pest Management Conference, Riverside

rodent-borne disease• Rodent-borne disease ecology and awareness Peter Bonkrude, Larry Bronson: NPS staff training, Lava Beds National Monument

• Hantavirus update: lessons learned Larry Bronson: Butte County Mosquito and Vector Control District annual training session, Oroville

• The chipmunks of California Joseph Burns: Southern California Mosquito and Vector Control Association of California (MVCAC) and Southern California Vector Education Cooperative Continuing Education Program, Anaheim

• Conducting small mammal trapping for disease surveillance Joseph Burns: MVCAC/CDPH Continuing Education Category D Program, Garden Grove

• Plague and hantavirus: a brief history of rodent-borne disease Curtis Fritz: San Joaquin Valley Epidemiologists Network, Sacramento


June 2009


• Hantavirus cardiopulmonary syndrome, tick-borne relapsing fever, and plague Michael Niemela: Boy Scouts of America staff training, Camp Wolfeboro

• Hantavirus and plague safety brief Jim Tucker: U.S. Forest Service (USFS) Lake Tahoe Basin Management Unit, South Lake Tahoe

• Rodent-borne diseases in California Jim Tucker: Nevada County Public Health, Nevada City

Flea-borne disease• Plague biology and control Peter Bonkrude o Plumas County Agriculture Department continuing education program, Quincy

o Butte County Mosquito and Vector Control District continuing education program, Oroville

• Decreasing the risks of plague to wildlife and humans using easily applied ground squirrel baits Richard Davis: Symposium on the Ecology of Plague and its Effects on Wildlife, Fort Collins, Colorado

• Plague and hantavirus Curtis Fritz: Epidemiology & Control of Infectious Diseases (PH 253B), School of Public Health, University of California, Berkeley

tick-borne disease• A tale of two trailers: relapsing fever in Mono County Joseph Burns: 76th Annual Conference of the MVCAC, Palm Springs

• Tick-borne diseases Marty Castro: Public Information Forum, San Geronimo

• Tick-borne disease in the North Bay: biology, risk, and personal protection Marty Castro: Marin-Sonoma/MVCAC Continuing Education Workshop, Cotati

• Ticks, tick-borne diseases, and associated risks Richard Davis: Pecho Coast Trail Docents, PG&E Diablo Canyon, San Luis Obispo

• Tick-borne relapsing fever in a visitor to Yosemite National Park, 2006: a collaborative investigation Curtis Fritz: Council of State and Territorial Epidemiologists Annual Conference, Denver, Colorado

• Prevalence and identity of rickettsiae in Dermacentor ticks from southern California Renjie Hu: 76th Annual Conference of the MVCAC, Palm Springs

• Does Spot get spots? Survey for canine cases of Rocky Mountain spotted fever in California Anne Kjemtrup, Laura Krueger: 76th Annual Conference of the MVCAC, Palm Springs



June 2009

• Molecular investigations have changed assumptions about Babesia and other piroplasm parasites infecting humans and animals Anne Kjemtrup: Vector-Borne Infectious Diseases: Changing Patterns (PHR 214), University of California, Davis

• Zoonotic Babesia Anne Kjemtrup: Epidemiology of Zoonoses (PHR 212), University of California, Davis

• Use of prescribed burn for tick control in California chaparral Kerry Padgett: 76th Annual Conference of the MVCAC, Palm Springs

Mosquito-borne disease• Overview of arbovirus surveillance and risk assessment Marty Castro: Laguna de Santa Rosa Ludwigia Taskforce Meeting, Cotati

• West Nile virus update and future program Marty Castro: Sonoma County Infectious Disease Taskforce, Santa Rosa

• State West Nile virus risk analysis Richard Davis: MVCAC South San Joaquin Region Quarterly Meeting, Taft

• Surveillance for mosquito-borne encephalitis virus activity in California, 2007 Tina Feiszli: 76th Annual Conference of the MVCAC, Palm Springs

• California mosquito-borne disease surveillance program, 2007 Tina Feiszli: MVCAC South San Joaquin Region Continuing Education Program, Visalia

• Best management practices for mosquito control on California state properties Tim Howard: MVCAC Sacramento Valley Region Continuing Education Program, Yuba City

• Pesticide resistance in California mosquitoes – An overview Tim Howard o 76th Annual Conference of the MVCAC, Palm Springs

o MVCAC Northern San Joaquin Region Continuing Education, Stockton

• ULV mosquito control Tim Howard: MVCAC Southern California Region Continuing Education Program, Prado Dam

• Epidemiology and prevention of West Nile virus and Lyme disease in California Anne Kjemtrup: Epidemiology & Control of Infectious Diseases (PH253B), University of California, Berkeley

• Epidemiology of WNV for the clinician with emphasis on the California experience Anne Kjemtrup: national web-based seminar sponsored by Kroeger Associates

• West Nile virus: surveillance and clinical issues Anne Kjemtrup: statewide web-based seminar sponsored by San Diego County Department of Health

• West Nile virus: the ecological connection Anne Kjemtrup: Central Veterinary Conference West, San Diego


June 2009


• West Nile virus activity in California 2007 Vicki Kramer: 74th Annual American Mosquito Control Association (AMCA) Conference, Sparks, Nevada

• West Nile virus in California Vicki Kramer: 76th Annual Conference of the MVCAC, Palm Springs

• Fall flooding and mosquitoes: a public health risk Jonathan Kwan: Fall Flood Meeting, Sacramento-Yolo Mosquito and Vector Control District, Elk Grove

• West Nile virus in California Michael Niemela: Nevada County West Nile Task Force, Nevada City

• The history of the West Nile virus in California Michael Niemela: MVCAC Northern San Joaquin Regional Continuing Education Meeting, Stockton

caltrans storMwater project• Understanding stormwater best management practices Marco Metzger: 74th Annual American Mosquito Control Association Conference, Sparks, NV

• Underground stormwater treatment systems Marco Metzger: MVCAC Northern San Joaquin Valley Region Continuing Education Program, Stockton

• Balancing water runoff management with vector control Marco Metzger: Santa Ana Regional Water Quality Control Board, Riverside

• Public health concerns associated with stormwater management Marco Metzger: Nuisance Water Management and Public Health Workshop, Ontario

• Mosquito prevention in stormwater BMPs Marco Metzger: 76th Annual Conference of the MVCAC, Palm Springs

u.s. Forest serVice• Synergistic agreement: how the California Department of Public Health and United States Forest Service Region 5 Challenge Cost-Share Agreement saves lives and money Joseph Burns: 23rd Vertebrate Pest Conference, San Diego

• Vector-borne diseases in USFS Region 5: an update for safety officers Mark Novak: U.S. Forest Service Safety Workshop, Pacific Grove

national park serVice• California Department of Public Health and National Park Service: a collaborative effort to prevent vector-borne diseases in NPS staff and visitors Curtis Fritz o West Coast Epidemiologists Conference, Yreka

o NPS staff and concessionaires training, Yosemite National Park



June 2009

• Vector-borne diseases in Yosemite Michael Niemela: NPS staff and concessionaires training, Yosemite National Park

other Vectors and public health pests• Detection and identification of Bartonella quintana in body lice from homeless persons in San Francisco Denise Bonilla: Society for Vector Ecology Annual Meeting, Fort Collins, Colorado

• Guidelines for the prevention and control of bed bug infestations in California: perspectives from local health departments Anne Kjemtrup, Laura Krueger: Quarterly Epidemiology Meeting, California Department of Public Health, Sacramento

• Taxonomy and ecology of the forensically important flies of California Michael Niemela: Forensic Entomology class, University of California, Davis

Vector control technician certiFication prograM• Exam review session o Denise Bonilla: San Francisco, San Jose (2)

o Jonathan Kwan: Fresno, Garden Grove, Ontario, Visalia o Michael Niemela: Elk Grove (2)

Miscellaneous• An update on bartonellosis Denise Bonilla: Bay Area Biologists Meeting

• CDPH Cooperative Agreement and pesticide use reporting Larry Bronson: MVCAC Sacramento Valley Region Continuing Education Session, Yuba City

• Bat basics: biology, health concerns, and management Richard Davis: Southern California MVCAC and SEVEC Continuing Education Program, Anaheim

• Fieldwork – challenges for a new generation Richard Davis: 76th Annual Conference of the MVCAC, Palm Springs

• Health education 101: Elements to planning a campaign Claudia Erickson: 76th Annual Conference of the MVCAC, Palm Springs


June 2009


Posters• Introduction of the scorpion Centruroides exilicauda into a suburban Los Angeles Basin neighborhood Larry Bronson, Laura Krueger: 76th Annual Conference of the MVCAC, Palm Springs

• Public health pesticide use in California and the impact of West Nile virus Tim Howard, Mark Novak: 74th Annual AMCA Conference, Sparks, Nevada

• Timothy Tickfinder: Don’t Let the Ticks Bite Anne Kjemtrup: 11th International Congress on Lyme Borreliosis and Other Tick-Borne Diseases, Irvine

• Mortality of non-target arthropods from an aerial application of pyrethrins Jonathan Kwan, Mark Novak, Michael Niemela. 76th Annual Conference of the MVCAC, Palm Springs

• Detection and relative prevalence of Borrelia miyamotoi sensu lato in California Ixodes pacificus Kerry Padgett: 11th International Congress on Lyme Borreliosis and Other Tick-Borne Diseases, Irvine

• Plague activity in California: a summary of statewide public health surveillance, 1984-2007 Jim Tucker: Symposium on the Ecology of Plague and its Effects on Wildlife, Fort Collins, Colorado



June 2009

Publications

Carney RM, Husted S, Jean C, Glaser C, Kramer V. Efficacy of aerial spraying of mosquito adulticide in reducing incidence of West Nile virus, California, 2005. Emerging Infectious Diseases 2008; 14:747-54.

Crosbie SP, Koenig WD, Reisen WK, Kramer VL, Marcus L, Carney R, Padolfino E, Bolen GM, Crosbie LR, Bell DA, Ernst HB. Early impact of West Nile virus on the yellow-billed magpie (Pica nuttalli). The Auk 2008; 125:542-50.

Davis RM, Cleugh E, Smith RT, Fritz CL. Use of a chitin synthesis inhibitor to control fleas on wild rodents important in the maintenance of plague, Yersinia pestis, in California. Journal of Vector Ecology 2008; 33:278-84.

Feiszli T, Husted S, Kjemtrup A, Park B, Eldridge B, Fang Y, Reisen W, Jean C, Cossen C, McQuarry A, Kramer VL. Surveillance for mosquito-borne encephalitis virus activity in California, 2007. Proceedings and Papers of the 76th Annual Conference of the Mosquito and Vector Control Association of California, 2008.

Harbison jE, Metzger ME, Hu R, Fritz CL, Kramer VL. Effect of conveyance pipe dimension and orientation on mosquito oviposition in a simulated stormwater management device. Journal of the American Mosquito Control Assocation 2008; 24: 98-104.

Henn jB, Metzger ME, Kwan jA, Harbison jE, Fritz CL, Riggs-Nagy j, Shindelbower M, Kramer VL. Development time of Culex mosquitoes in stormwater management structures in California. Journal of the American Mosquito Control Association 2008; 24:90-7.

Kwan jA, Riggs-Nagy jM, Fritz CL, Shindelbower M, Castro PA, Kramer VL, Metzger ME. Mosquito production in stormwater treatment devices in the Lake Tahoe Basin, California. Journal of the American Mosquito Control Association 2008; 24:82-9.

Levine jR, Fritz CL, Novak MG. Occupational risk for exposure to rodent-borne hantavirus at U.S. Forest Service facilities in California. American Journal of Tropical Medicine & Hygiene 2008; 78:352-7.

Margolis DA, Burns j, Reed SL, Ginsberg MM, O’Grady TC, Vinetz JM. Case report: Septicemic plague in a community hospital in California. American Journal of Tropical Medicine and Hygiene 2008; 78:868-71.

Metzger ME, Myers CM, Kluh S, Wekesa JW, Hu R, Kramer VL. An assessment of mosquito production and nonchemical control measures in structural stormwater best management practices in southern California. Journal of the American Mosquito Control Association 2008; 24:70-81.

Salkeld DJ, Leonhard S, Girard YA, Hahn N, Mun J, Padgett KA, Lane RS. Identifying the reservoir hosts of the Lyme disease spirochete Borrelia burgdorferi in California: the role of the western gray squirrel (Sciurus griseus). American Journal of Tropical Medicine and Hygiene 2008; 79:535-40.

Wikswo ME, Hu R, Dasch GA, Krueger L, Arugay A, Jones K, Hess B, Bennett S, Kramer V, Eremeeva ME. Detection and identification of spotted fever group rickettsiae in Dermacentor species from southern California. Journal of Medical Entomology 2008; 45:509-16.


June 2009


Peer reviewIn 2008, VBDS staff served as peer reviewers for 19 manuscripts submitted to the following scientific journals:

• Acta Parasitologica (1)• American Journal of Tropical Medicine and Hygiene (1)• Emerging Infectious Diseases (1)• Folia Parasitologica (1)• Journal of the American Mosquito Control Association (4)• Journal of the American Veterinary Medical Association (1)• Journal of Clinical Microbiology (1)• Journal of Medical Entomology (1)• Journal of Parasitology (2)• Journal of Vector Ecology (2)• Journal of Veterinary Internal Medicine (1)• Journal of Veterinary Parasitology (1)• Vector-Borne and Zoonotic Diseases (2)



June 2009

VBDS Reports and Public Information MaterialsNewly developed or revised in 2008

Rodent-borne Diseases

• Hantavirus Cardiopulmonary Sydrome, fact sheet (revised)• Facts About HPS in California, brochure (revised)

Flea-borne Diseases

• Compendium of Plague Control (updated)

Mosquito-borne Diseases

• West Nile Virus Activity – North Coastal Region, seasonal monthly e-newsletter• Best Management Practices for Mosquito Control on California State Properties, report• California Mosquito-borne Virus Surveillance and Response Plan (updated)• Operational Plan for Emergency Response to Mosquito-borne Disease Outbreaks • Location of Neglected Swimming Pools (updated) • Information for Real Estate Managers on Neglected Pools (updated) • Fight the Bite, 2008-2009 calendar • Best Management Practices For Mosquito Control On California State Properties • What You Should Know About Mosquito Control and Pesticides (updated) • Overview of Mosquito Control Practices in California (updated) • Protect Your Horse from WNV, flier –English, Spanish

Other Vectors and Public Health Pests

• Kjemtrup A, Krueger L, Hu R. Survey results from California health agencies on bed bug infestations in California. California Environmental Health Association Bulletin, Summer 2008: 7-9.

• Swimmer’s Itch, fact sheet• Facts About Conenose Bugs in California, brochure• Scabies, fact sheet• Easy to Read Bed Bug, fact sheet• Africanized Honeybees, fact sheet (revised)• Lyme Disease in California, brochure—English, Spanish (revised)• A Parent’s Guide to Headlice, brochure (revised)• Guidelines on head lice prevention and control for school districts and child care facilities, 2008

Vector Control Technician Certification Program

• Pesticide application and safety training for applicators of public health testicides, training manual (revised)

• The biology and control of mosquitoes in California, training manual (revised)


June 2009


AcknowledgementsRodent-borne Disease SurveillanceU.S. Department of Agriculture (USDA) Forest Service (USFS); U.S. Department of Interior, National Parks Service (NPS); Alameda County Vector Control and Services District (VCSD), Coachella Valley Mosquito and Vector Control District (MVCD); Contra Costa MVCD; El Dorado Public Health Department; Los Angeles County Department of Public Health (DPH); Mono County Health and Human Services (HHS); Napa County Mosquito Abatement District (MAD); Northwest MVCD; Orange County Vector Control District (VCD); Riverside County Vector Control Program (VCP); San Bernardino County VCP; San Diego County Vector Surveillance and Control Program (VSCP); West Valley MVCD; University of California, Santa Barbara; Viral and Rickettsial Diseases Laboratory (VRDL), California Department of Public Health (CDPH).

Flea-borne Disease SurveillanceUSDA Animal and Plant Health Inspection Service, Wildlife Services; NPS; Alameda County VCSD; El Dorado County Environmental Management Department (EMD); Fresno County Department of Agriculture; Inyo County Department of Environmental Health; Kern County Environmental Health Services (EHS); City of Long Beach HHS; Los Angeles County Agricultural Commissioner/Weights & Measures and DPH; Mono County HHS; Napa County MAD; Nevada County Department of Environmental Health; Orange County Health Care Agency and VCD; Plumas County Public Health Agency Environmental Health Division (EHD); Riverside County VCP; San Bernardino County VCP; San Diego County VSCP; San Mateo County MVCD; Santa Barbara County Mosquito and Vector Management District; Ventura County EHD; West Valley MVCD; School of Veterinary Medicine, University of California, Davis (UCD); Microbial Diseases Laboratory Branch, CDPH.

Tick-borne Disease SurveillanceUnited States Army Center for Health Promotion and Preventative Medicine-West; Division of Vector-Borne Infectious Diseases, U.S. Centers for Disease Control and Prevention (CDC); Rickettsial Zoonoses Branch, CDC; Rocky Mountain Laboratories, National Institutes of Health; Alameda County VCSD; Calaveras County Department of Environmental Health; El Dorado County EMD; Inyo County Department of Environmental Health; Lake County VCD; Los Angeles County DPH; Mono County Environemtnal Health; Napa County MAD; Orange County VCD; Riverside County VCP; Sacramento-Yolo MVCD; San Mateo County MAD; Santa Cruz County MVCD; Sonoma County Public Health Laboratory; West Valley MVCD.

Mosquito-borne Disease SurveillanceCalifornia Animal Health and Food Safety Laboratory; California Department of Food and Agriculture (CDFA); Mosquito and Vector Control Association of California; participating local health departments, physicians and veterinarians, and local mosquito and vector control agencies; Center for Vectorborne Diseases, UCD; Center for Advanced Research of Spatial Information, Hunter College of The City University of New York; VRDL and Veterinary Public Health Section, CDPH.

Caltrans Stormwater ProjectCaltrans; University of California, Riverside, Aquatic Entomology Laboratory; Orange County VCD; San Diego County VSCP.

Other Vectors and Public Health PestsCDFA; Coachella Valley MVCD; Los Angeles County Agricultural Commissioner/Weights & Measures; Los Angeles County DPH; Orange County VCD; San Gabriel Valley MVCD; San Francisco Department of Public Health; San Francisco Housing and Homeless Programs; Alameda VCD; San Francisco, San Jose, and Los Angeles Project Homeless Connect; CDC



June 2009

VBDS student assistants and dead bird hotline staffYaffa Alter, Chris Bass, Lakeyssia Brown, Anna Cragin, Sandra Crossley, Clarence DeGuzman, Laura Diaz, Eduard Flores, Kristine Galang, Carol Hegstrom, Long Her, Kimberly Holbrook, Stephanie Hwa, Margaret Kerrigan, Joanne Kim, Grace Laylay, Laura Leypoldt, Angus Mullins, Laurel Ormiston, Elizabeth Sigman, Erin Trimble, James Suchy

Annual Report technical assistanceLinda Sandoval

State of CaliforniaCalifornia Department of Public Health

June 2009


California Department of Public HealthVector-Borne Disease Section1616 Capitol Avenue, MS 7307

P.O. Box 997377Sacramento, CA 95899-7377

Telephone: (916) 552-9730www.cdph.ca.gov/programs/vbds

infectious diseases branch division of …sandiegohealth.org/disease/dhs/vbd_ca_annual_2008.pdf ·...

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