Studies on dispersal of malaria vectors in a hilly tract of Koraput District, Orissa State, India.

Dispersal of malaria vectors was studied in a hilltop village in Koraput, a highly malarious district of Orissa. Immatures from terraced stream beds and day-time resting adults from artificially dug pit shelters, distributed centrifugally at different distances from the village were sampled. Breeding of Anopheles fluviatilis, An. annularis and An. culicifacies was found up to a distance of 1,700 m. Immature density of An. fluviatilis and An. culicifacies showed a negative correlation with the distance, but they were not statistically significant. The maximum distance at which An. fluviatilis adult females collected was 1,500 m. A significantly negative correlation was observed between An. fluviatilis resting females and distance. An. culicifacies adults were collected in low numbers even in the nearest pit shelters. No An. annularis was recorded from the pit shelters. The present record on the dispersal range of An. fluviatilis is estimated to be higher than that reported elswhere in India.