Comparison of Plasmodium falciparum infectivity to Anopheles dirus D using direct and indirect blood feeding methods

Membrane feeding method (indirect blood feeding) using defibrinated blood has been established and was found to be as good as the direct feeding method with no singificant differences in the production of oocysts and sporozoites in Anopheles dirus D (p > 0.05). However, lsuccessful feeding was greater in the direct feeding method (69.4 per cent) when compared to the membrane feeding method (46.7 per cent) (p <0.0001). Based on 19 malaria patients who had > 400 gametocytes per ul of blood, the effect of antimalarial drugs on oocyst and sporozoite rates was also studied and it was found that mefloquine treated patients produced reduced infection and infectivity in an. dirus D than those who received antimalarial drugs other than mefloquine. Patients who had gametocytes and have been treated for causes other than malaria and who did not receive any antimalarial drugs were found to produce the highest infection and infectivity rates in An. dirus D (p < 0.0001).

"DMR-larval trap" for possible control of Aedes aegypti (L), the pricipal vector of DHF in Yangon

The Department of Medical Research (DMR) has developed a larval/pupal trap with a view to control Aedes (Stegomyia) aegypti (L) effectively and economically. "DMR-larval trap" is a mechanical device and is capable of trapping all stages of larvae and pupae and that the number of aquatic stages trapped is directly proportional to the number of larvae and pupae present in the container-habitat. The trap is also capable of trapping greater number of late stages than the earlier ones which is more favourable from control point of view. It is found to trap about 47.85 per cent of all larvae and pupae within the first 24 hours achieving complete control within 10 days with sustained control thereafter.

Laboratory studies on the larvicidal activity of Bacillus Sphaericus-2362 and 2297 against Anopheles dirus and Anopheles annularis

The larvicidal efficacy of Bacillus sphaericus -2362 and 2297 was tested against larvae of Anophales Dirus (Mudon strain) and Anophales annularis (DDT-resistant strain from Sittwe), using the method of Dubitskij (1) with some modifications. The results showed that although both the strains of B.sphaericus were effective larvicides, strains 2363 was found to be much more potent than strain 2297. Anopheles dirus was also found to be more susceptible than An.annularis. Larval cadavers were found to play an important role in the maintenance and recycling of B.sphaericus-2362.