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Dengue Fever 2002

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Dengue Fever 2002

  1. 1. Presented to the BSSWG at the CDC By Linda Whiteford, Ph.D, M.P.H. With the Assistance of Beverly Hill, M.Ed. July 29, 2002 Dengue Fever: The Failure of Surveillance?
  2. 2. Overview The 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.
  3. 3. 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.
  4. 4. Dengue Clinical Syndromes  Undifferentiated fever  Classic dengue fever  Dengue hemorrhagic fever (DHF)  Dengue shock syndrome (DSS)
  5. 5. 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 pandemic 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.
  6. 6. 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, 1978 Gubler, D. & Kano, G. (1997). Dengue and Dengue Hemmorhagic Fever. CAB International. New York, NY.
  7. 7. 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 cases Colombia = 22,781 reported cases Cuba = 10,586 reported cases
  8. 8. Dengue in Cuba Pan American Health Organization, 2002 1824 Epidemic 1850 Cases reported 1905 Dengue epidemic 1944 Epidemic 1977 Den-1 epidemic 1979 75, 692 cases Den-1 1981 1st major DHF epidemic 2000 Den-3 & Den-4 cases
  9. 9. 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
  10. 10. Dengue in the DR Pan American Health Organization, 2002 1960 Avg. of 570 cases/year 1963 Den-3 cases reported 1977 Den-3 isolated during dengue epidemic 1982 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
  11. 11. Dengue in the DR (cont’d) 1990 2 DHF cases 1991 7 DHF cases 1998 176 DHF cases, 10 deaths 2000 3,400 DF, 58 DHF cases, 6 deaths 2001 719 DF cases, 4 DHF cases 2002 146 DF cases, 1 DHF cases (week 11) Pan American Health Organization, 2002
  12. 12. 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
  13. 13. Cuban Response to Dengue D e n g u e F e v e r E r a d ic a t io n in C u b a , 1 9 8 1 I n s e c t ic id e s p r a y in g F o g g in g o f d w e llin g s S a n it a r y la w s C o n t a in e r d is p o s a l H e a lt h e d u c a t io n O p e n h o s p it a liz a t io n C u b a n G o v e r n m e n t S o u r c e R e d u c t io n A c t io n P la n : H u m a n r e s o u r c e s - 1 5 , 0 0 0 w o r k e r s E c o n o m ic R e s o u r c e s - $ 4 3 m illio n 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.
  14. 14. 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.
  15. 15. Health Education Campaign  Utilized the mass media  Built upon previous governmental activities  Developed community-based prevention programs  Engendered a high degree of community participation 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.
  16. 16. 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.
  17. 17. 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.
  18. 18. 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.
  19. 19. 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.
  20. 20. 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).
  21. 21. 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).
  22. 22. 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).
  23. 23. 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).
  24. 24. 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.
  25. 25. 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)
  26. 26. 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.
  27. 27. 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 future PAHO/WHO, 2002
  28. 28. PAHO Integrated Strategy  Integrated epidemiological & entomological surveillance  Advocacy & implementation of intersectoral actions  Effective community participation  Environmental management  Patient care, inside & outside of the health system PAHO/WHO, 2002
  29. 29. 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
  30. 30. 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
  31. 31. 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.

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