Seasonality of adult Culex quinquefasciatus and transmission of bancroftian filariasis in Pondicherry, south India.

Seasonal variations in biting Culex quinquefasciatus and transmission of bancroftian filariasis were investigated in Pondicherry, South India. The biting density of C. quinquefasciatus, the principal vector species, was lowest in the summer months and higher during the monsoon and winter months. The survival of the vectors as indicated by the proportion of parous mosquitoes was found to be less in the summer season. Biting mosquitoes with infective stage larvae were not encountered during the hottest months of May, June and July and the early monsoon month of August indicating seasonality of transmission. Maximum transmission took place between November and March. These findings suggest that vector control measures according to the season of transmission may produce more cost-effective results than year round control operations.