Comparison of geographical strains of Schistosoma mansoni in the rhesus monkey.

Rhesus monkeys were infected with strains of Schistosoma mansoni from Puerto Rico, St Lucia, Brazil, and Tanzania. Monkeys were killed 11-14 weeks after exposure to 600-650 cercariae. Some differences in the behaviour of different strains were noted, but the similarities between the strains were more remarkable. The only strain difference observed in both mice and monkeys was a prolonged prepatent period in animals infected with the Mwanza strain. The results of experimental infections are believed to be of little value in predicting possible differences in the pathogenicity of schistosome strains for man.