A unique methodology for detecting the spread of chloroquine-resistant strains of Plasmodium falciparum, in previously unreported areas, by analyzing anophelines of malaria endemic zones of Orissa, India.

Generally, clinical data is referred to study drug-resistance patterns of Plasmodium falciparum in an area. This is only possible after a clear manifestation of drug-resistance parasites inside the human host, and thereafter detection by healthcare persons. The detection of spread of drug-resistant P. falciparum in a population, before any pathological symptoms detected in humans is possible by analyzing the anopheline vectors, transmitting malaria. In the present study we implemented a new strategy to detect the spread of chloroquine-resistant (CQR) strains of P. falciparum by the major malaria vectors prevalent in selected endemic regions of Orissa, India. We screened P. falciparum positive vectors by using polymerase chain reaction (PCR)-based assay and thereafter detected K76T mutation in the Pfcrt gene, the chloroquine-resistance marker, of parasites present within the vectors. This study showed higher transmission rate of chloroquine-resistant P. falciparum parasites by Anopheles culicifacies and Anopheles fluviatilis. This study will help in assigning chloroquine-resistant P. falciparum sporozoite transmission potential of malaria vectors and suggest that by adopting the mentioned methodologies, we can detect the spreading of the drug-resistant P. falciparum in its transmission. This approach of studying the anophelines during regular vector collection and epidemiological analysis will give the knowledge of chloroquine-resistance pattern of P. falciparum of an area and help in devising effective malaria control strategy.