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Distribution of schistosome genetic diversity within molluscan intermediate hosts

Published online by Cambridge University Press:  06 April 2009

D. J. Minchella
Affiliation:
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
K. M. Sollenberger
Affiliation:
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
C. Pereira De Souza
Affiliation:
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA

Summary

Naturally infected Biomphalaria glabrata snails were collected at two sites near Belo Horizonte, Brazil, and Schistosoma mansoni cercariae isolated from single snails were used to infect individual mice. Genetic comparison of single worm DNA was accomplished by hybridization of Southern blots to a polymorphic repetitive DNA element. Genetic profiles of parasite individuals revealed a diverse array of parasite genotypes in naturally infected intermediate hosts. The observed distribution of schistosome genotypes among intermediate hosts indicates that over half of the infected snails harbour multiple miracidia. Snails were more likely to carry multiple infections than expected by chance. This degree of overdispersion combined with high levels of genetic variability facilitates multi-genotype transmission and helps maintain parasite genetic diversity.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1995

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