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Fact Sheet: Dengue and Dengue Hemorrhagic Fever
CLINICAL FEATURES
- Sudden onset of
fever, severe headache, myalgias and arthralgias, leukopenia, thrombocytopenia
and hemorrhagic manifestations
- Occasionally produces
shock and hemorrhage, leading to death
ETIOLOGIC AGENT
- Dengue viruses
(DEN-1, DEN-2, DEN-3 and DEN-4) - flaviviruses
INCIDENCE
- Variable, depending
on epidemic activity.
- Globally, there
are an estimated 50 to 100 million cases of dengue fever (DF) and several
hundred thousand cases of dengue hemorrhagic fever (DHF) per year
- Average case fatality
rate of DHF is about 5%
- In 1995, 250,000
cases of DF and 7,000 cases of DHF reported in Americas
- Between 100 to
200 suspected cases introduced into U.S. each year by travelers
SEQUELAE
COSTS
- $250 million estimated
in Puerto Rico in past 10 years
TRANSMISSION
- Mosquito-borne
(Aedes aegypti)
RISK GROUPS
- Residents of or
visitors to tropical urban areas
- Increased severe
and fatal disease in children under 15 years
- No cross-immunity
from each serotype
- A person can theoretically
experience four dengue infections
SURVEILLANCE
- Active, laboratory-based
surveillance in Puerto Rico and the U.S. Virgin Islands
- In U.S., passive
surveillance of imported cases reported to CDC and other reference laboratories
- Laboratory-based,
passive surveillance in endemic areas
TRENDS
- Resurgent disease
worldwide in the tropics
- Epidemics are larger
and more frequent
- Transmission in
continental U.S. in 1995; first since 1986
- Since first epidemic
in 1981, DHF now reported from 18 countries in the Americas
- Evolution of disease
pattern in Americas similar to SE Asia in 1950s and 1960s
CHALLENGES
- Increased incidence
associated with increased urbanization
- Rapid dispersal
of viruses via air travel
- Emergency control
methods ineffective
- Severe hemorrhagic
disease poorly understood by physicians in Americas
- Change emphasis
from emergency response to prevention of epidemics
- Develop better
government-based programs
- Encourage community
participation in prevention and control programs
OPPORTUNITIES
- Dengue Branch,
NCID, designated WHO Reference Center
- Improve laboratory-based
international surveillance
- Educate medical
community
- Develop community-based,
integrated prevention programs
RESEARCH PRIORITIES
- Develop improved
laboratory-based international surveillance
- Develop rapid,
sensitive and specific diagnostic tests
- Develop more effective
community-based prevention programs
- Develop tetravalent
dengue vaccine
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