Stauffer, Jay R.4; Madsen, Henry5; Rollinson, David3
1 Parasitology and Aquatic Diseases, Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, Københavns Universitet2 Pennsylvania State University3 The Natural History Museum4 Pennsylvania State University5 Parasitology and Aquatic Diseases, Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, Københavns Universitet
increasing the threat of human urogenital schistosomiasis?
For the last 15 years, we have studied the relationships among cichlid snail-eating fishes, intermediate snail-host density, and the prevalence of human infection of Schistosoma haematobium in Lake Malaŵi and concluded that the increase of human infection is correlated with the decrease in snail-eating fishes in the shallow waters of the lake. We postulated that a strain of S. haematobium from other parts of Africa, which was introduced into the Cape Maclear region of Lake Malaŵi by tourists, was compatible with Bulinus nyassanus-which is a close relative of B. truncatus, and interbred with the indigenous strain of S. haematobium, which ultimately produced via introgression a strain that can use both B. globosus and B. nyassanus as intermediate hosts. This actively evolving situation involving intermediate snail-host switching and decline of Trematocranus placodon, a natural cichlid snail predator, will impact on transmission of urogenital schistosomiasis within the local communities and on tourists who visit Lake Malaŵi.