ケニア国クワレ地区のビルハルツ住血吸虫症の流行地におけるBulinus globosusとCleopatra ferrugineaの相互作用

Snail survey data collected in a small village in Kenya from April 1984 to March 1991 were used to analyze the interaction between Bulipuus globosus (intermediate host of Schistosoma haematobium) and Cleopatra ferruginea (unsusceptible snail). An inverse correlation was observed between the two snail populations. This finding leads to the suggestion that C. ferruginea has limiting effects on B. globosus population. The relative penetrative activity of S. haematobium miracidia into the two snail species was also examined. Miracidia penetrated C. ferruginea as well as B. globosus. Although selective mass-chemotherapy has been repeated every 2 years in our study area, the low infection rates in B. globosus were recorded in the year when large numbers of C. ferruginea and small numbers of B. globosus were collected. Therefore, C. ferruginea seems to diminish the transmission of S. haematobium; C. ferruginea reduce the number of S. haematobium miracidia which reach to B. globosus