Chikungunya fever usually lasts 3-7 days. It is rarely fatal. The etiologic agent, chikungunya virus, is arthropod-borne and has been placed in the family Togaviridae, genus Alphavirus. Human infections are acquired by the bite of infected Anopheles aegypti mosquitoes, and epidemics are sustained by human-mosquito-human transmission.
Chikungunya virus has been isolated from humans and mosquitoes in eastern, southern, western, and central Africa and in southeastern Asia, where it has been responsible for illnesses in hundreds to thousands of individuals. The virus has been implicated as the cause of epidemics in Asian countries including the Philippines, Thailand, Cambodia, Vietnam, India, Myanmar (Burma) and Sri Lanka. Similarities between clinical appearances of chikungunya and dengue fever probably account for misclassification and under-reporting of chikungunya fever in areas with endemic dengue.