Chloroquine resistant malaria in West Malaysia.

Chloroquine resistance is a well established entity in South East Asia, and presents a problem of increasing importance. Strains of P. falciparum resistant to chloroquine have also been found to be resistant to amodiaquine and a combination of pyrimethamine and sulphadoxine. Knowledge of the drug sensitivity of the strains of malaria parasite in a given locality is important so that the right choice of drugs can be made in treatment of the disease. The treatment of chloroquine resistant malaria in West Malaysia is a subject of another paper but suffice it to say that increased doses of chloroquine have still been found to be effective in treating many cases of falciparum malaria from areas of chloroquine resistance.

Studies on immunization against Brugia malayi infection in the rhesus monkey.

Recent studies on immunity to helminthic infection have shown that some degree of protective immunity may be stimulated by inoculations of attenuated living worms or their metabolites. The present experiments were designed to observe the effects of attempted immunization in the rhesus monkey by the use of attenuated infective larvae of Brugia malayi.Some effect was observed in animals inoculated with larval incubate, in which microfilaraemia did develop, but at low levels and for short durations. However, the most strking finding was that persistent immunity to challenge infections (expressed as failure to cause microfilaraemia) was obtained in animals vaccinated with large numbers (200) of infective larvae attenuated by X-irradiation at 20 000 R.Experiments with different numbers of larvae attenuated by different doses of irradiation suggest that there is an optimum combined effect of these two factors in eliciting functional antibody in a quantity sufficient to prevent patent infection in Malayan filariasis.

Studies on the relationship between fluorescent antibody response and ecology of malaria in Malaysia.

The fluorescent antibody (FA) technique was used to detect the presence of malarial antibody in populations living in 3 different ecological areas of Malaysia. Serum samples were tested using Plasmodium falciparum, P. vivax, P. malariae and P. fieldi antigens. An area of hyperendemic malaria had a good correlation between the antibody responses and active parasitaemias. The percentage and intensity of responses increased with the age of the individuals. In an area of hypoendemic malaria, each of 17 sites had ecological conditions which would favour or discourage the transmission of malaria. The reasons for high FA responses in some villages and low responses in others were readily apparent. The effect of even limited control programmes on the malarial ecology could be measured by an examination of the antibody responses. An aboriginal population receiving suppressive drugs had FA responses indicating both past experience and the effect of the drug programme.