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. 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. 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. Dengue Clinical Syndromes
 Undifferentiated
fever
 Classic dengue
fever
 Dengue
hemorrhagic fever
(DHF)
 Dengue shock
syndrome (DSS)

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.

7. 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.

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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.

15. 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.

16. 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.

17. 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.

18. 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.

19. 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.

20. 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.

21. 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).

22. 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).

23. 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).

24. 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).

25. 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.

26. 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)

27. 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.

28. 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

29. 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

30. 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

31. 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

32. 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.