SPATIO-TEMPORAL DISTRIBUTION OF THE SNAILS Physa acuta, POTENTIAL HOSTS of Schistosomiasis of Schistosoma haematobium IN KATANA AREA

Schistosoma mansoni, the blood fluke responsible for human intestinal schistosomiasis exists in Katana region and it's hosted by the snail Biomphalaria Pfeifferi. But Schistosoma haematobium responsible of urinary schistosomiasis has not been reported in that area. The appearance of its intermediate host Physa acuta in the region attracts our attention about future infestation. The objective of this study is to determine the distribution area of this species which appears in region. The snail collection was done in 25 sites comprising 14 streams and rivers, 3 groups of ponds, 7 springs and Lake Kivu.These sites are grouped in terms of altitude gradient and the frequency of people and domestic animals. The results show that altitude has an effect on the distribution of Physa acuta in the region. The snail was collected in streams and ponds compared to sites located at the Lake and in rivers. They were found in the site where the ecological conditions were favorable (water velocity, aquatic vegetation and also water quality). The absence of snails in some elevations is related to the ecological factors which reduce the survival of Physa acuta. The risk of local transmission of urinal schistosomiasis in Katana is predictable as its potential intermediate host Physa acuta is now present and largely distributed in the region.