Physiographic and entomologic risk factors of malaria in Assam, India.

Fever surveys were conducted in several districts of the Indian state of Assam to ascertain the prevalence of malaria in relation to vector abundance, entomologic inoculation rates (EIRs), and geographic location of human settlements. Anopheles minimus were incriminated, but their relative abundance and biting rates varied among districts, and no significant correlation was observed between these two indicators (r = 0.43, P = 0.

Associations of antifolate resistance in vitro and point mutations in dihydrofolate reductase and dihydropteroate synthetase genes of Plasmodium falciparum.

Background: Antifolate antimalarials like sulfadoxine-pyrimethamine are used as second-line treatment for Plasmodium falciparum malaria patients who fail to respond to chloroquine. The efficacy of the sulfa-pyrimethamine combination in the treatment is also compromised by the development of resistance in the parasite. Resistance to these drugs has been shown to encode with point mutations in dihydrofolate reductase and dihydropteroate synthetase genes.

Y-chromosome polymorphism in species B and C of Anopheles culicifacies complex.

Isofemale cultures of wild-caught Anopheles culicifacies collected from 11 localities representing different ecoepidemiological zones on the mainland of India were identified by examining both F1 male larval mitotic karyotypes and polytene chromosomes of half-gravid F1 adult females. All cultures identified as species A by polytene chromosome examination had submetacentric Y chromosomes. In species B and C, some isofemale cultures had acrocentric Y chromosomes, whereas others were submetacentric.