The chikungunya virus is an arbovirus in the genus Alphavirus in the Togaviridae family. It is spread by Aedes aegypti and Ae. albopictus, both day-biting mosquitoes. Humans are the reservoir host. Transmission to mosquitoes is greatest in the first week of infection when the patient has high viremia.
Cases have been reported from mother to child when the mother is viremic during pregnancy. In utero transmission may result in miscarriage or infection at birth. No cases of transmission from breast milk have been reported. So far no cases of transmission through blood transfusion have been seen, but some laboratory-acquired cases have occurred.
Chikungunya life cycle. Image courtesy CDC.