Observations on population density of Culex quinquefasciatus and transmission indices of Bancroftian filariasis during and after Integrated Vector Management strategy.

An Integrated Vector Management strategy, implemented as an alternative to the conventional control operations that include mainly chemical control in Pondicherry, South India, reduced very substantially the population density of Culex quinquefasciatus. This resulted in drastic decrease in the intensity of transmission of bancroftian filariasis transmitted by Culex quinquefasciatus and consequently the incidence of new infections in children of 0-5 age group was minimized. When the IVM strategy was withdrawn after five years of implementation and conventional control measures were re-adopted, resilience of Culex quinquefasciatus population was observed and human exposure to the risk of infection increased. The results suggest that maintenance of vector density at reduced levels for prolonged periods, is necessary to control infectious diseases like filariasis, which is difficult in the present day urban situations in developing countries. Hence the emphasis should be on chemotherapy to achieve control of lymphatic filariasis.