A comparative study of prevalence and spatial distribution of major Anopheline vector fauna in a hyper- and a hypomalaria endemic district of Odisha, India with special reference to onset of first wet season

摘要

The state’s retrospective findings indicate the incidence of malaria deaths, whichis more during the onset of first monsoon season. Based upon this fact, our objective was tostudy the distribution pattern of major Anopheles vectors in two endemic districts viz. Kalahandiand Cuttack of Odisha, India that differ significantly according to malariogenic stratification,under the impact of first monsoon shower. A comparative study of vector abundance,predominance, their habitats, resting site preference, impact of abiotic rhythm (light/darkperiod) on vector distribution, gonotrophic status as well as sporozoite rate was establishedin a high and a low endemic district of Odisha, when the degree of malaria transmissionelevates to its peak level Anopheles culicifacies was found to be predominant in hyperendemicKalahandi district while Anopheles subpictus was abundant in hypo-endemic Cuttackdistrict. Both primary vector An. culicifacies and the secondary vector An. subpictus mostlyprefer CS (Cattle shed) compared to HD (Human dwelling) in Kalahandi district where asthere was slight shifting of resting habitat of An. culicifacies from CS to HD in Cuttackdistrict. Anopheles culicifacies prefers to rest on wall besides objects in Kalahandi while nosuch site preference was observed in Cuttack district. On the other hand, distribution of An.subpictus was highly influenced by the daily rhythm of light/dark cycle (i.e. day and night) inCuttack. The gonotrophic condition revealed the high tendency of the predominant vectorstowards endophilic resting. The sporozoite rate was 0.66% in Kalahandi and nil in Cuttackdistrict. The proper monitoring of vector prevalence and distribution, at least during the peaktransmission period can avert a perpetuated upsurge in malaria.