Cause of Dengue Fever
Dengue fever is caused by the dengue virus, which has four distinct serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. This means a person can be infected up to four times in their lifetime, once by each serotype. Infection with one serotype usually provides lifelong immunity to that type, but only temporary immunity to the others. Subsequent infections by different serotypes increase the risk of severe dengue (like dengue hemorrhagic fever or dengue shock syndrome).
Transmission
Vector: The primary vector is the Aedes aegypti mosquito, though Aedes albopictus can also spread the virus.
How it spreads:
A mosquito becomes infected after biting a person who has dengue virus in their blood.
The virus incubates in the mosquito for 8–12 days, after which the mosquito can spread it to others when it bites again.
Dengue is not spread person-to-person directly.
High-Risk Areas
Common in tropical and subtropical climates: Southeast Asia, the Indian subcontinent, Africa, Central and South America, the Caribbean, and parts of the Pacific Islands.
Urban areas with poor water management and sanitation are especially vulnerable, as mosquitoes breed in standing water.
Additional Notes
Mosquitoes that spread dengue bite mostly during the day, especially in early morning and before dusk.
Climate change, urbanization, and global travel have contributed to the increased spread of dengue worldwide.
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