Single sex cercariae of Schistosoma mansoni , a comparison of male and female infectivity

Over 90% of Schistosoma haematobium and S. mansoni infections show a dominance of male worms in experimental animals. Male: female ratios as high as 5: 1 are common in S. haematobium (Ghana) infections and 1·5: 1 is a typical ratio in S. mansoni infections. The male parasite seems to be more successful than the female in reaching maturity. To test this theory experiments were set up to compare the infectivity of male and female cercariae.