Transmission dynamics & epidemiology of malaria in two tribal districts in Madhya Pradesh, India

BACKGROUND AND OBJECTIVES Epidemiology and transmission of malaria vary within the tribal areas with the variation in topography, forest cover and type of forest. For the control of disease, understanding of the dynamics of transmission in the varied ecological situation is essential. This study was carried out in the two distinct tribal areas- Baiga Chak (thick forested area) of Dindori district and Bichhia block (forest fringe area) of Mandla district, Madhya Prasdesh, India, to understand the epidemiology and transmission dynamics of malaria. METHODS Mosquitoes were collected using hand catch and whole night collections to determine the proportion of vectors, their density and seasonality. Vector incrimination was done by sporozoite ELISA and feeding preferences of vector by gel diffusion method. Active fever surveys were carried out fortnightly to determine the age specific malaria parasite rates among the inhabitants of two areas. RESULTS Density of Anopheles culicifacies was significantly higher in Bichhia while the density of An. fluviatilis was higher in Baiga Chak. An. culicifacies was incriminated from both the areas while An. fluviatilis was incriminated from Baiga Chak only. Malaria slide positivity rate (SPR) was significantly higher (OR=3.7 95%CI, 3.1-4.4) in Baiga Chak (28.2%) than Bichhia (9.6%). INTERPRETATION & CONCLUSIONS The features of malaria transmission in tribal areas differed from those reported in rural or semirural population. Site-specific and region-specific studies are required to develop appropriate intervention measures to control malaria.