In vitro sensitivity to antimalarial drugs and polymorphisms in Pfg377 gene in Plasmodium falciparum field isolates from Mewat, India.

The malaria infection is the interplay of several complex factors, among which drug resistance and gametocyte biology are the crucial ones. Measurements of the drug sensitivity assays and prevalence of gametocyte genes play a major role in malaria eradication programmes. The purpose of this study was to assess the current drug sensitivity profile in the field isolates and type the Pfg377 gene. In vitro drug sensitivity assay was used to assess the susceptibility of Plasmodium falciparum field isolates collected from Mewat (Haryana), located in Northern region of India to four anti-malarial drugs. The inhibitory concentrations (IC50) for the four drugs viz Chloroquine (CQ), Artesunate (AS), Sulphadoxine (SD) and Pyrimethamine (PYR) were in the range of 10.11-113.2, 2.26-4.08, 13.31-43.91 and 0.76-4.91 nM respectively in the evaluated 25 field isolates. The Pfg377 allele typing in the 26 field isolates revealed different types of haplotypes (A, B, C and D) varying by the size and number of repeats and deletions. The Pfg377 allelic types in the cryopreserved and adapted isolates of P. falciparum were compared to determine the parasite lines in them. The allele types or presence of different clones in the same sample could not be correlated significantly with resistance to any of the four drugs tested in the study. Our study revealed different drug sensitivity profiles of field isolates from Mewat region and allele typing of Pfg377 gene revealed different haplotypes of field isolates were circulating in parasite population.