Presented to the BSSWG at the CDCBy

Linda Whiteford, Ph.D, M.P.H.With the Assistance of Beverly Hill, M.Ed.

July 29, 2002

Dengue Fever:The Failure of Surveillance?

OverviewThe dengue virus: Is an arbovirus/flavivirus Is transmitted by mosquitoes Is composed of single- stranded RNA Consists of four serotypes: (DEN-1, 2, 3, 4) Causes DF/DHF/DSS

Centers for Disease Control, 2001.

Aedes aegypti Female mosquito

transmits dengue A daytime feeder Lives near human

dwellings Prefers artificial

containers in which to lay eggs/produce larvae

Bromeliads are a natural place of origin

Centers for Disease Control, 2001.

Dengue Clinical Syndromes

Undifferentiated fever

Classic dengue fever Dengue

hemorrhagic fever (DHF)

Dengue shock syndrome (DSS)

The History of Dengue First dengue-like symptoms in China,

AD 265-420 First major outbreak, French West Indies,

1635 Dengue-like illnesses in Asia, Africa and

North America, late 1700s DHF identified around 1780 DF/DHF now a worldwide pandemicWhiteford, L.M. (2000). Local Identity, Globalization, and Health in Cuba and the Dominican Republic. Global Health Policy, Local Realities. Lynne Rienner Publishers Inc. Boulder, CO.

Dengue incidence in Latin America

Dengue epidemics in Caribbean, post WWII

Invasion of Southeast Asia, 1950s-1960s

Reinvasion of the Americas, 1970s-1980s

Jamaica & Cuba, 1977 Puerto Rico &

Venezuela, 1978Gubler, D. & Kano, G. (1997). Dengue and Dengue Hemmorhagic Fever.

CAB International. New York, NY.

DHF in Latin America From 1981-2001, Cuba had the highest incidence of DHF

worldwide, after Venezuela and Colombia, respectively.

Pan American Health Organization, 2002

Venezuela = 45,799 reported casesColombia = 22,781 reported casesCuba = 10,586 reported cases

Dengue in Cuba Pan American Health Organization, 2002

1824 Epidemic1850 Cases reported1905 Dengue epidemic1944 Epidemic1977 Den-1 epidemic1979 75, 692 cases Den-11981 1st major DHF epidemic2000 Den-3 & Den-4 cases

Dengue in Cuba (cont’d) For all of 2001, Cuba has reported

11,432 DF cases.

As of week 18 of 2002, 3,011 case of dengue fever were reported, including 12 DHF cases: Serotype 3.

Source: PAHO in Travel Medicine Program, PPHB, Health Canada Accessed at: http://www.hc-sc.gc.ca/pphb-dgspsp/tmp-pmv/2002/df0327_e.html

Dengue in the DR Pan American Health Organization, 2002

1960 Avg. of 570 cases/year1963 Den-3 cases reported1977 Den-3 isolated during dengue

epidemic1982 Den-4 reported (1st time in DR)1984 Den-1 reported (1st time in DR)1985 Den-2 reported (1st time in DR)1988 1st reports of DHF, 4 cases, 2

deaths

Dengue in the DR (cont’d)1990 2 DHF cases1991 7 DHF cases1998 176 DHF cases, 10 deaths2000 3,400 DF, 58 DHF cases, 6 deaths2001 719 DF cases, 4 DHF cases2002 146 DF cases, 1 DHF cases (week

11) Pan American Health Organization,

2002

The 1981 Cuban Outbreak May, 1981:

344,203 reported cases

July, 1981:11K+ cases at peak

2/3 of deaths (101 cases) occurred in children < 15 years

158 total deaths

Cuban Response to Dengue

D en g u e F ever E rad ica tion in C u b a , 1 9 8 1

In sec tic id e s p rayin gF og g in g o f d w e llin g s

S an ita ry law sC on ta in er d isp os a l

H ea lth ed u ca tionO p en h osp ita liza t ion

C u b an G overn m en tS ou rce R ed u c tion A c tion P lan :

H u m an resou rc es - 1 5 ,0 0 0 w ork ersE con om ic R esou rces - $ 4 3 m illion

Whiteford, L.M. (2000). Local Identity, Globalization, and Health in Cuba and the Dominican Republic. Global Health Policy, Local Realities. Lynne Rienner Publishers Inc. Boulder, CO.

Environmental Surveillance

Disposal containers treated with insecticides

Malathion sprayed from airplanes Portable blowers used to fog dwellings Sanitary laws enforced disposal of

containers Workers trained as “vector controllers”

Whiteford, L.M. (2000). Local Identity, Globalization, and Health in Cuba and the Dominican Republic. Global Health Policy, Local Realities. Lynne Rienner Publishers Inc. Boulder, CO.

Health Education Campaign Utilized the mass media Built upon previous governmental

activities Developed community-based

prevention programs Engendered a high degree of

community participationWhiteford, L.M. (2000). Local Identity, Globalization, and Health in Cuba and the Dominican Republic. Global Health Policy, Local Realities. Lynne Rienner Publishers Inc. Boulder, CO.

Hospitalization Policy Mobile field hospitals were established. A liberal policy was implemented:

116,151 admitted & treated (33.7% of all reported cases)

Results: Significantly lowered morbidity & mortality rates

Whiteford, L.M. (2000). Local Identity, Globalization, and Health in Cuba and the Dominican Republic. Global Health Policy, Local Realities. Lynne Rienner Publishers Inc. Boulder, CO.

Human & Economic Resources

Human resources

15 provincial directors 60 entomologists 27 general supervisors 729 team leaders 3,801 inspectors 1,947 vector

controllers

Economic resources

US $43 million was spent, primarily on insecticides, but also on the extensive personnel pool.

Whiteford, L.M. (2000). Local Identity, Globalization, and Health in Cuba and the Dominican Republic. Global Health Policy, Local Realities. Lynne Rienner Publishers Inc. Boulder, CO.

Effective control procedures?

If the 1981 campaign against dengue fever was so effective in controlling the epidemic, the question “Why was there another major outbreak in 1997?” must be asked.

The 1997 Cuban Outbreak 2,946 lab-confirmed cases of DF 205 DHF cases 12 fatalities No deaths below the age of 16 The above cases were detected via a

system of active surveillance, which also excluded other febrile syndromes, but reported them as suspected dengue fever cases.

Khouri & Guzman, et. Al. (1998). Reemergence of Dengue in Cuba: A 1997 Epidemic in Santiago de Cuba. Emerging Infectious Diseases, Vol. 4. No. 1.

Passive & Active Surveillance: Dengue Eradication in Cuba

Passive surveillance:

Established at the end of the 1981 epidemic

Suspected patients were tested (ELISA)and no positive cases were identified

Active Surveillance: Established in January, 1997 Cases detected on 01/28,

now believed to be the first, although initial transmission probably occurred in 12/96

Prevented extension of the outbreak to the other 30 municipalities of Cuba

Khouri & Guzman, et. Al. (1998).

Passive Surveillance in 1981

Infection was ruled out via clinical & epidemiological investigation, although secondary infections of DEN-1 & DEN-2 were confirmed as main risk factors for DHF/DSS through serological testing.

No mosquitoes were found in patients’ residence localities. No indigenous transmission could be established from 1981-1996. Reinfestation has occurred in some areas, however; In Santiago de

Cuba, for instance, due to imported tires transporting Ae. aegypti in 1992.

Khouri & Guzman, et. Al. (1998).

Active Surveillance in 1997

Sought out febrile patients at high risk in the primary health-care subsystem of Santiago de Cuba January-July of 1997

60,000 cases were found in ER’s from 11/1-1/28.592 were compatible with dengue fever.154 cases were determined via home interviews, but no + cases were reported, when tested using ELISA.

Khouri & Guzman, et. Al. (1998).

Active Surveillance Outcomes

Secondary infections were present in 100 of 102 (98%) of DHF/DSS cases.

In fatal cases, secondary infections were documented in 11 of 12 (92%) of cases.

Youngest case was a 17-year-old, which speaks to the possibility of life-long “enhancing” antibodies.

Khouri & Guzman, et. Al. (1998).

Potential Confounding Variables

Breakdown of the vector control campaign

Asymptomatic and subclinical dengue cases are frequent, especially in children

Increased knowledge since 1981 allowed a more accurate classification of DHF/DSS cases, increasing the case-fatality rate in 1997.

Cuban Dengue Outbreak, 2002

Increased urbanization Decreased sanitation Water shortages No American aid Rising prices on

imported foods

A result of globalization?

(IDRC, Pravda & The Militant, 2002)

Why the outbreak in 2002?

Contributing factors include:

Water supply less reliable than past years, particularly in Havana = more water storage occurring.

Due to the success of the 1997 campaign, the government relaxed vigilance on community-based clean-up campaigns = more trash, dead leaves, bromeliads to serve as breeding places for vectors.

Epidemiological surveillance of sentinel cases failed to detect/identify nacent outbreaks.

Barriers to Dengue Control Lack of community ownership Local health services not sufficiently established Behavioral change strategies are weak & unincorporated Water supply & solid waste management are limited in

high risk areas Competing forces limit sustainability & continuity of

control actions Little capacity for intersectoral coordination A dearth of operational research on individual &

community-based strategies There is no vaccine for dengue fever and will not be in the

near futurePAHO/WHO, 2002

PAHO Integrated Strategy Integrated epidemiological &

entomological surveillance Advocacy & implementation of

intersectoral actions Effective community participation Environmental management Patient care, inside & outside of

the health systemPAHO/WHO, 2002

PAHO Integrated Strategy (cont’d) Case reporting Incorporation of the subject of dengue

into formal education Critical analysis of the use/function of

insecticides Formal health training of professionals

& workers, in medical and social areas Emergency preparedness

PAHO/WHO, 2002

How do we get there? Policy Training Operative alliances Technical assistance Consultation Monitoring Evaluation Epidemiological data

Incorporate a social-communication component:

Behavior changes that occur sequentially must be understood and addressed to avoid the “silver bullet” approach.

Formal health training of health workers & providers must be the central point.

PAHO/WHO, 2002

Summary More attention to early

warning systems must be a priority.

Proactive community control activities must not cease.

A constant, reliable water supply is essential.

Relaxed vector control must not continue.