Intermediate Host Snails of Human Schistosomes in the Senegal River Delta: Spatial Distribution According to Physicochemical Parameters

Abstract

The objective of the study was to evaluate the influence of physicochemical parameters of water on the spatial distribution of snail intermediate hosts of human schistosomes in the Senegal River Delta. Eight water points in three endemic villages for schistosomiasis were selected for biweekly monitoring of snail numbers and physicochemical parameters of water at the beginning of the rainy season. The results show that the spatial distribution of snail populations is a function of certain parameters. The pH, the dissolved oxygen and its saturation, and the temperature have a positive influence on the Bulinus and Biomphalaria, while the conductivity , the speed of flow, and the salts (phosphates, salinity, and nitrates) seem to act negatively on the populations of these snails.