Influence of pattern of exposure, parasite genetic diversity and sex on the degree of protection against reinfection with Schistosoma mansoni
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This paper analyzed, experimentally, the influences of pattern of exposure, parasite genetic diversity, and parasite sex on the degree of protection against reinfection with Schistosoma mansoni in the mouse. The results show that, (1) in infections with one male parasite genotype, successive infections induced a significant decrease in the infectivity of the parasite and significant increases in the spleen and liver weights compared to mass infections, (2) successive infections with one male genotype induced a significant decrease in the infectivity of the parasite compared to successive infections with five male genotypes, and (3) genotype infectivities were determined by the order at which they were used in the successive infections. These results are discussed in terms of protective effect and concomitant immunity and provide an ecological explanation of the natural sex-biased dispersal toward the male schistosomes.
KeywordsMale Infection Spleen Weight Female Infectivity Parasite Genotype Male Genotype
This work was supported financially by the French Ministère des Affaires étrangères and the CNRS. We thank Andreas Ruppel for input on the manuscript and Salim Al Yafae and Bernard Dejean for technical assistance. The laboratory where this experimental work was done is a WHO Collaborating Center.
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