Studies on the morphology and compatibility between Schistosoma hæmatobium and the Bulinus sp. complex (gastropoda: planorbidae) in Cameroon

Abstract

A description is given of the morphological variation of the shell, the radula features and the copulatory organ of Bulinus sp. (2n=36) from four populations in the western Cameroon crater lakes. To assess the
role of diploid snails belonging to the Bulinus natalensis/tropicus complex in the transmission of urinary schistosomiasis in Cameroon, the relation between Bulinus sp. (from four Cameroon crater lakes) and Schistosoma haematobium (from three transmission foci) were studied. Bulinus sp. in the
present study refers to the diploid snail (2n=36) tentatively identified as Bulinus natalensis or as Bulinus tropicus in the Cameroon crater lakes. The percentage infection of snails challenged ranged from 03.33 to 06.00% for Nchout Monoun population and from 01.85 to 04.76% for Monoun Ngouondam population. No progeny from Petponoun-East and Petponoun-West were experimentally successfully infected with S. haematobium. All the 351 snails dissected were euphallic. Previous malacological surveys revealed the absence of Bulinus sp. naturally infected with human schistosomes. These results suggested that Bulinus sp. was not susceptible to infection with S. haematobium in the Cameroon Western highland crater lakes. These observations justify the absence of transmission foci (for urinary schistosomiasis) in this area.