| Risk Assessment and Management Solutions for Arthropod-borne and Infectious Diseases |
RAMS-AID Research - Dengue Decision Support System Project
Introduction to dengue
Basic facts about dengue
- Dengue is caused by four related, but antigenically distinct, dengue viruses (DENV-1, DENV-2, DENV-3, DENV-4) of the Flavivirus genus
- Outcomes of infection with dengue virus ranges from asymptomatic to mild or moderate disease (dengue fever) and to severe disease (dengue hemorrhagic fever)
- It is estimated that 50-100 million dengue fever cases and several hundred thousand dengue hemorrhagic fever cases occur each year in subtropical and tropical parts of the world
- Case fatality rates for dengue hemorrhagic fever range from <1% with appropriate supportive care to >20% without such care
- Dengue virus is transmitted primarily by the yellow fever mosquito Aedes aegypti
- Vector control is the primary means for dengue prevention and control because a vaccine against dengue virus is lacking
Click on the map below to view an enlarged image
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| Map from WHO |
Dengue fever and dengue hemorrhagic fever cases are increasing
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| Graph from WHO |
The dengue virus transmission cycle
- Dengue virus is maintained in a mosquito-human cycle involving Aedes aegypti and occasionally also other Aedes mosquitoes including Aedes albopictus
- The extrinsic incubation period for dengue virus in the mosquito can vary with temperature but typically is in the 1-2 week range
- The intrinsic incubation period for dengue virus in the human host most commonly is 4-8 days
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| Schematic from CDC |
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| The yellow fever mosquito Aedes aegypti | Image from CDC |
- Aedes aegypti is a day-time feeder with peak biting activity in the morning and afternoon
- The female mosquito is exquisitely adapted to exploiting the domestic environment; she most commonly feeds indoors (endophagy) and rests indoors (endophily) and, if there are breeding sites available inside the home, she may not even leave the house to lay her eggs
- The female can lay eggs indoors or outdoors in a variety of containers including bottles, cans, flower pots, vases, buckets, pet bowls, tires, wash basins etc.
Aedes aegypti and dengue in the Americas
Aedes aegypti has re-emerged in the Americas following a successful hemispheric
eradication campaign during the 1950s and 1960s
Image from CDC
The resurgence of Aedes aegypti resulted in the re-emergence of dengue in the Americas
| Total number of dengue cases reported to WHO – data from WHOs DengueNet | |
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| 1960-1965 | 1970-1975 |
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| 1980-1985 | 1990-1995 |
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| 2000-2005 | |