Distribution of fresh water snail intermediate host of trematode parasites in some fresh water bodies in Makurdi, Nigeria

The distribution of fresh water snail intermediate host of trematode parasites in an area is a bio-indicator of trematodiasis transmission in the locality. The distribution of some fresh water snail species in some fresh water bodies in Makurdi, Benue State, was carried out in four selected sites between June and September, 2016. It was aimed at determining the abundance of freshwater intermediate host of trematode parasites in the study-area. The scoop net method was employed with hand picking technique to collect snails, while morphological identification of snail was done using key in the Handbook of Danish Bilhaziasis Laboratory. Some physico-chemical parameters of water were also investigated at each site, 1,743 snails were collected. The distribution was: Melanoides tuberculate, 65.7%; Bulinus forskalii, 17.0%; Bulinus globosus,12.2%; Bulinus truncates, 4.5%; and Indoplanorbis exustus, 0.6 % respectively (x2 = 2422, df = 4, p<0.001). Snails distribution at various locations was: Ishwa Dam 71.4%; North Bank of River Benue 14.5%; Ityomu 7.9%; and Fete 6.1% (x2 = 1854, df = 12, p<0.001). The monthly distribution of the snail vectors also revealed a significant difference (x2 = 182, df = 9, p<0.001) in the snail species occurrence at the various sites. The population of the snails increased from June through September. This was accompanied by a decrease in the pH, biological oxygen demand (BOD) and dissolved oxygen (DO) in the water bodies, while temperature, turbidity and phosphate levels increased. This study has shown that there were significant intermediate hosts of Schistosoma haematobium, the causative agent of urinary schistosomiasis in the study area. Therefore, there is a need to undertake adequate snail control program and environmental sanitation awareness in the study area to curb the potential transmission of trematode parasitic diseases.Keywords: Fresh water; snail; intermediate host; trematode; physico-chemical parameters