Importance of the aquatic weed Ceratophyllum to transmission of Schistosoma haematobium in the Volta Lake, Ghana.

Results of 5 years of sampling for Bulinus rohlfsi in human-water contact sites of villages along the Volta Lake, Ghana, have confirmed that the aquatic macrophyte, Ceratophyllum, is the most important ecological factor for sustaining high levels of cercarial transmission of Schistosoma haematobium. Data available so far indicate that growth of this weed largely determines the size of the snail populations. Increasing density of Ceratophyllum correlates with increasing levels of cercarial transmission potential in the water contact sites and of S. haematobium infection in the village populations.