Dengue:
It is a mosquito borne viral illness. Dengue epidemics have been known since last 300 years. West Indies noticed epidemic in 1635. First confirmed epidemic was reported from Philippines in 1953-1954. Since then Southeast Asia is experiencing major outbreaks with increasing morbidity and mortality. Some countries are having Dengue outbreaks every year.

Problem statement:


Indian perspective:

India, Sri Lanka and Myanmar are considered hyperendemic for Dengue fever because of significant increase in the proportions of dengue cases with severe disease. According to WHO, in India, Dengue Hemorrhagic fever is an emergent disease in view of frequent cyclical epidemics and circulation of multiple virus serotypes at present.

Dengue virus:
It is member of Genus flavivirus and family flaviviridae, having single stranded RNA with 4 serotypes: DEN - 1, 2, 3, and 4. All serotypes have potential for causing epidemic and are antigenically similar but different enough to elicit cross protection for only a few months after infection by any of them.

Vector:
Dengue virus is transmitted from person to person by Aedes mosquito. A.aegypti is the most important epidemic vector. Vertical transmission from mother to child has been reported from Bangladesh and Thailand.

Host factor:
Dengue virus infects humans and lower primates. Human (Man) is considered as its urban reservoir. Studies in Africa and Malaysia demonstrated that monkeys are infected with Dengue virus and are the likely reservoir hosts.