Susceptibility of the malaria vectors to insecticides in Bangladesh.

Insecticide susceptibility tests with diagnostic dosages of 4% DDT and 5% malathion concentrations conducted at field sites on the two important principal malaria vectors namely, Anopheles dirus and An. philippinensis have been reported. They are found to be susceptible to DDT and malathion. The implication of the use of insecticides in controlling malaria is also discussed.

Incrimination of Anopheles aconitus Donitz as a vector of epidemic malaria in Bangladesh.

In 1989-91, post-monsoon epidemics of vivax malaria occurred in the central flood plain near Dhaka. Anopheles philippinensis, the usual vector in the paddy field habitat, was not present, but 1.4% of parous An. aconitus were infective. This is only the second time An. aconitus has been incriminated as a vector in Bangladesh. We speculate that the surprising increase in lowland malaria may have been caused by environmental change that favored the survival of An. aconitus.

Distribution and chromosomal polymorphism of the malaria vector Anopheles dirus species D.

Preliminary results indicate that species D of the Anopheles dirus complex is widespread west of the Thai-Burma border in Burma and Bangladesh. A chromosomal study of An. dirus species D in these areas has revealed that this malaria vector is highly polymorphic for chromosomal rearrangements in salivary gland polytene chromosomes. The data from the limited number of wild-caught samples suggest that different geographically isolated populations may occur with respect to the frequency of inversions 2La, 3Ra and 3La. The distribution of chromosomal polymorphisms may be associated with the geography and epidemiology of human malaria in this region.