Bulinus nyassanus is an intermediate host for Schistosoma haematobium in Lake Malawi.

At Cape Maclear on the Nankumba Peninsula, close to the southern end of Lake Malawi, Schistosoma haematobium is highly prevalent in the local people and many tourists become infected with this parasite each year. A ‘Bilharzia Control Programme’ was initiated in this area in August 1998, as a development collaboration between the Government of Malawi, the Danish Agency for Development Assistance (Danida), and the Danish Bilharziasis Laboratory. Although Bulinus globosus is a known host for S. haematobium, B. nyassanus has not previously been incriminated as an intermediate host. However, schistosome-infected B. nyassanus were discovered in surveys to identify transmission sites on the peninsula. Experimental infections of wild-caught B. nyassanus with S. haematobium proved successful and S. haematobium eggs were found in hamsters experimentally exposed to cercariae retrieved from schistosome-infected, field-collected B. nyassanus. These are remarkable observations since, although there are very few reports...