tick borne infections
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Tick Borne Infections
Daniel J Anderson, MD
EpidemiologyEcologyClinical CharacteristicsDiagnosisTreatmentPrevention
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Tick-Borne InfectionsChallenges
Expanding / changing geography of ticks / infections
New infections / newly recognized “old” infections
Newly identified -- new Ehrlichia species 2011
Old infections | new to MN -- Powassan fever, RMSF
Clinical clues that might suggest tick-borne infection
Fever plus [rash, severe headache, mild hepatitis]
low blood cell counts [esp platelets]]
Diagnostic tests -- blood smear, serology, PCR
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EpidemiologyEcologyClinical
DiagnosisDifferential Diagnosis
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EPIDEMIOLOGY
Tick Borne Infections - MN/WI
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Lyme disease
Anaplasmosis
Ehrlichiosis
Babesiosis
Powassan Fever
RMSF (Rocky Mountain Spotted Fever)
Tick Borne Infections - MN/WI
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Tick Borne Infections - MN
Daniel J Anderson, MD
Lyme1,293 cases in 2010
(21 % increase from 2009)
Anaplasma720 cases in 2010
( > 100 % increase from 2009)
Ehrlichia New species of Ehrlichia reported 2011
Babesia 56 cases in 2010 (31 in 2009)
Powassan(50 cases in all of US 1958-2009 )
6 MN cases 2008 - 20101 MN death from Powassan 2011 (at ANW)
RMSF2000 cases / year in all of US
Sporadic cases in MN1 death in MN 2009
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http://www.health.state.mn.us/divs/idepc/diseases/lyme/highrisk.html
Risk of Tick-borne infection is not uniform throughout the state. The highest risk is central and SE sections
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More Anaplasma than Lyme in Aitkin, Beltrami, Cass,
Crow Wing & Hubbard counties
The risk of different tick-borne infections also is not
uniform throughout the state
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RMSF annualincidence isincreasing
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Ecology
Tick Borne Infections - MN/WI
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Ticks <> Diseases
Daniel J Anderson, MD
TICK
Ixodes scapularis
AnaplasmosisLyme disease
BabesiosisPowassan Fever
Ambyloma americanum
EhrlichiosisRMSFSTARI
Tularemia
Dermacentor variabilis Dermacentor andersoni
RMSFTularemia
DISEASEORIGIN
Endogenous
“Imported” (returning from travel)
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Comparison of ticks
Lyme, Anaplasma, Babesia, Powassan
Ehrlichia, STARI, Tularemia, RMSF
RMSF, Tularemia
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Blacklegged tick (Deer Tick)Ixodes scapularis
Lyme, Anaplasmosis, Babesiosis,& Powassan
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Lone Star tickAmblyoma americanum
Ehrlichia, RMSFSTARI, Tularemia
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American dog tickDermacentor variablis
RMSF, Tularemia,Human Monocytic Ehrlichiosis
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Brown dog tickRhipicephalus sanguineus
RMSF
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Clinical
Tick Borne Infections - MN/WI
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Tick Borne IllnessesFever, chills, myalgias, arthralgias
Fever, chills, rash
Fever, chills, CNS findings
(encephalitis / paresis / paralysis / focal findings)
Hepatitis / transaminitis
Leukopenia, thrombocytopenia, anemia
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Diagnostic Clues / HintsAppropriate Exposure Potential
Suggestive Symptoms
Fever, rash, arthralgias, headache, neurologic findings
Exam
Rash, splenomegaly
Labs
Low peripheral blood cell counts (esp thrombocytopenia)
Mild transaminitis / hepatitis
Blood smear, serologies, nucleic acid based tests (NATs)
CSF analysis
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Lyme
3-30 days after tick bite (BEFORE fever)Erythema migrans (EM) 70 - 80 % of patients get rash
STARIVery similar to Lyme disease“expanding Bull’s Eye” lesions
RMSF
90 % -- usually 2 - 5 days AFTER feverInitially small pink macules on wrists / anklesLATER petchial
TularemiaSkin ulcer w regional lymphadenopathy
RASH
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Hgb Platelets LFTs WBC
Lyme Disease
RMSF anemialow
plateletstransaminitis leukopenia
AnaplasmosisEhrlichiosis
Babesiosis
PowassanFever
anemia transaminitisleukopenia
then leukocytosis
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Lyme Disease
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LymePathogen. Borrelia burgdorferi (spirochete)
Clinical
EM rash, Bell’s palsy, AV block, CNS, Arthropathy
Co-infection -- ~ 5-10 % with Anaplasma || ~ 2 % with Babesia
Dx
IgM: HGA can cause false + IgM for Lyme
IgM can persist for years (even if no clinical disease)
After 8 weeks, should always have + IgG
Treatment -- no data for prolonged therapy
Prevention -- Doxycycline 200 mg if engorged tick < 72 h after bite
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Lyme DiagnosisClinical diagnosis (ie no serology needed) if exposure to deer tick AND
Bilateral Bell’s Palsy
III ° AV block or complete heart block [CHB]
Characteristic erythema migrans [EM] rash
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Lyme SerologyCriteria for positive
Western blot IgG ≥ 5 bands
Western blot IgM ≥ 2 bands
Chronology
Early IgM +
After 4-8 weeks
nearly all IgG + (regardless of RST test strain used)
SO, if IgG still negative > 8 weeks illness, then “+ IgM” is false +
IgM
HGA can cause false + IgM
+ IgM can persist for years ... may NOT correlate at all w clinical state
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Lyme Testing:Unvalidated tests with unproven use
Test assays whose accuracy and clinical usefulness have not been adequately established. Unvalidated tests available as of 2011 include:
• Capture assays for antigens in urine
• Culture, immunofluorescence staining, or cell sorting of cell wall-deficient or cystic forms of B. burgdorferi
• Lymphocyte transformation tests
• Quantitative CD57 lymphocyte assays
• “Reverse Western blots”
• In-house criteria for interpretation of immunoblots
Measurements of antibodies in joint fluid (synovial fluid)
IgM or IgG tests without a previous ELISA/EIA/IFADaniel J Anderson, MD
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Lyme PCR
Most useful for late arthritis if done on synovial fluid
Limited use in CSF
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Lyme Disease Treatment
Oral Therapy for all except neurological / late arthritis or initially for high degree AV block
IV therapy: for meningitis, late arthritis or initially for high degree AV block
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Lyme Disease Rx Duration2-3 weeks for most early infections - tho’ some data suggest 10 days sufficient
2-4 weeks for meningitis / arthritis
4-8 weeks for late arthritis
Prolonged courses of therapy? .
No proven benefit
There are proven adverse consequences (C diff, death, IV clots, ...)
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Lyme Disease Treatment
Reinfection rate rare (approximately 4 %)
Post Exposure Prophylaxis (PEP) -
single dose doxycycline 200 mg if < 72 hours
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Anaplasmosis
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Human Granulocytic Anaplasomsis [HGA]
Pathogen Anaplasma phagocytophilum
Clinical
up to 35 % coinfected with Lyme and/or Babesia
fever, chills, headache, myalgia, and malaise,cough, diarrhea, confusion, and lymphadenopathy,
17 % severe multisystem organ failure / SIRS / even death (Lyme does not do this)
rash is not common
Data
leukopenia, thrombocytopenia,
mild hepatitis / transaminitis
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Human Granulocytic Anaplasomsis [HGA]
Dx
Peripheral blood smear (in WBCs)
30 - 80 % + morulae
seen in granulocytes
Serology
NATs (PCR)
Treatment
Doxycycline (will also cover potential Lyme coinfection)
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Ehrlichiosis
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Human Monocytotropic Ehrlichiosis [HME]
Pathogens
E canis / E chaffeensis / / E muris
Clinical
< 50 % with rash (but more often than with HGA)
More common farther south than Anaplasmosis (HGA)
Data -- Lymphopenia, morulae RARE on blood smear (vs HGA)
Dx -- Serology, PCR
Treatment - doxycycline
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Daniel J Anderson, MD
AnaplasmosisHGA
EhrlichiosisHME
Farther northMN & WI
Farther southIowa & Missouri
~ 50 % morulaeon blood smear
RARELY seemorulae in blood smear
rash is RARErash more common
(though still < 50 %)
serology / PCR blood smear
serology / PCR
doxycycline doxycycline
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Babesiosis
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Babesiosis
Pathogen Babesia microtii (MN, WI, East coast), B divergens & B duncani in other locations
Clinical
fatigue/weakness/malaise followed within days by fever (>38° C) and one or more of the following: shaking chills, sweats, headache, myalgia, arthralgia, and anorexia
Malaise, myalgia, arthralgia, and shortness of breath differentiate babesiosis from other febrile illnesses
fatigue and malaise persist for several months
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BabesiosisDiagnosis
Blood smear (in RBCs)
Tetrad of ring forms
“Maltese Cross”
Serology
PCR
Treatment
Mild: atovaquone + azithromycin
Severe: clindamycin + quinine + exchange transfusion
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Less Common
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Powassan Encephalitis
Pathogen: Flavivirus
Same viral family as Dengue, Yellow Fever, West Nile
Clinical
50 % w focal neurologic signs / symptoms
Olfactory hallucinations & temporal lobe seizures (DDx Herpes encephalitis)
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Powassan EncephalitisData
Leukopenia first (the high WBC), thrombocytopenia, transaminitis
CSF lymphocytosis (usually < 100 cells)
MRI => thalamic, basal ganglia lesions
Dx => IgM (serum / CSF) /4 x increase serum IgG
Treatment => supportive
Dx => serologic (some cross reactivity with other flaviviruses (for example Dengue fever)
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RMSFPathogen Rickettsiae rickettsii
Clinical (2 - 14 day [median 7] incubation)
fever, headache, nausea / emesis / diarrhea
rash usually ~ 3 days AFTER other signs
begins wrists / ankles
Data
thrombocytopenia (sometimes anemia) WBC often nl
coagulopathy, DIC, CXR changes
Dx serology (? PCR on clinical specimens)
Treatment
doxycycline early in course illness
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Differential
Diagnosis
Tick Borne Infections - MN/WI
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Differential DiagnosesParalytic illnesses
Polio, Tick Paralysis, Guillain-Barré, Cervical cord lesion
Encephalitidies
Herpes simplex encephalitis (HSE) -- critical diagnosis because of the urgent need for intravenous acyclovir for HSE
Febrile illnesses with rash
Parvovirus B19, Measles, Meningococcal disease, others
Fever with transaminitis
Lyme, HGA, Babesiosis, Acute hepatitis (HBV, HAV, HCV)
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Diagnosis
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DiagnosisClinical
Lyme (rash, bilateral Bell’s palsy, III° AV block in o/w healthy pt)
Serological
Lyme, HGA, RMSF, Powassan
Blood / CSF (in CSF only IgM <> indicates local production)
NAT (Nucleic Acid based Tests)
Powassan Fever, HGA, Babesiosis
Blood / CSF
Peripheral Blood Smear evaluation
Babesiosis, HGA, HGE
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Clinical Summary
Daniel J Anderson, MD
LymeAseptic meningitis
Heart BlockRash, Arthritis
Anaplasma headache, low platelets, hepatitis, renal failure
Ehrlichia Headache, low cell counts, renal failure, hepatitis
Babesia fever, headache, pancytopenia
Powassan Encephalitis
RMSF Fever, severe headache, ... 3 days later rash
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Diagnosis Summary
Daniel J Anderson, MD
LymeClinical (III ° AV block, Bell’s Palsy, EM Rash)
Serology, Lumbar puncture
Anaplasma Blood smear, PCR, serology
Ehrlichia Blood smear, PCR, serology
Babesia Blood smear, PCR, serology
PowassanSerology
supporting evidence by head MRI
RMSF Serology
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Treatment Summary
Daniel J Anderson, MD
Lyme
Anaplasma doxycycline/ azithromycin
Ehrlichia doxycycline / azithromycin
Babesiaatovaquone + azithromycin
(for severe disease clindamyin + quinine + exchange transfuse)
Powassan supportive care
RMSF doxycycline
PO doxycycline / amoxicillin
IV ceftriaxone
2-4 weeks early4-8 weeks late disease /
arthritisno “long term” Rx
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Tick-borne InfectionsTick ecology changing (expanding geography of ticks)
New / Newly recognized infections
Fever, rash, low cell counts (esp thrombocytopenia), transaminitis
New diagnostic modalities (esp NAT-based testing)
Lyme testing (even western blot IgM) not necessarily definitive
Doxycycline -- Rx of choice - Lyme, Anaplasma / Ehrlichia, RMSF
Tick avoidance / prevention is the best
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Tick RemovalGrab Tick with tweezers close to skin
Pull steadily straight up
Clean area [alcohol, iodine, soap & H20]
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Daniel J Anderson, MD
Lyme, Babesia, HGAPowassan Fever
RMSF, Tularemia.Human Monocytic Ehrlichiosis
Ticks / Illnesses & Geography
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ReferencesThe Clinical Assessment, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infectious Diseases Society of America. Clin Infect Dis. (2006) 43 (9): 1089-1134 http://cid.oxfordjournals.org/content/43/9/1089.full
National Institue of Allergy and Infectious Diseases. Tickborne Diseases website. http://www.niaid.nih.gov/topics/tickborne/pages/default.aspx