Significance of coconut husk pits as larval habitats of Culex quinquefasciatus (Say) in the filariasis endemic coastal belt of Sri Lanka.

Extended surveys of coconut husk pits in three districts in a study of vectors of Japanese encephalitis showed that Cx. gelidus constituted 50.9% of the larval material in Panadurra, 77.7% in Allutgama and 75.2% in Talalla. Correspondingly, Cx. quinquefasciatus was 0, 4.1 and 0 percent respectively. A similar survey in Polhena, Matara, a well known filariasis endemic village showed 72.2% Cx. gelidus and 21.2% Cx. quinquefasciatus. Analysis of past records of husk pit surveys from seven other districts gave similar results. The reason for relatively higher breeding of Cx. quinquefasciatus in the husk pits at Polhena, Matara and a suggested vector control strategy are discussed.

The susceptibility of Liberian Culex quinquefasciatus to Wuchereria bancrofti in Sri Lanka.

Strains of Culex quinquefasciatus collected in Liberia showed low susceptibility to Wuchereria bancrofti from Liberian donors. However, when the same mosquito strains were fed on W. bancrofti donors from Sri Lanka they showed equally high susceptibility as Sri Lankan C. quinquefasciatus simultaneously fed on the same donors. A Liberian strain did not respond to selection for refractoriness. Thus the strains of W. bancrofti from Liberia and Sri Lanka differ in their ability to infect specific mosquito strains and it is concluded that Liberian C. quinquefasciatus could not provide genes for use in the construction of a refractory strain intended for the replacement of Sri Lankan vector populations.