Experimental host-induced selection in Schistosoma mansoni strains from Guadeloupe and comparison with natural observations

Abstract

Allelic frequency variation at the malate dehydrogenase (E.C. 1.1.1.37) polymorphic locus (Md/i-i) was analysed during several successive generations in four strains of Schistosoma mansoni from Guadeloupe, maintained experimentally on mice. A rapid evolution of the frequency of the Mdh-1 a allele is interpreted as being the result of an interaction between experimental drift and selection induced by the murine laboratory host. These experimental results are compared to the genetic structures observed among the corresponding natural populations of S. mansoni in Guadeloupe (West Indies). They strengthen the hypothesis of a natural host-induced selection by the murine host (Rattus rattus), which, in Guadeloupe, plays the role of host reservoir for this human schistosome.

Transmission of Schistosoma japonicum in Marshland and Hilly Regions of China: Parasite Population Genetic and Sibship Structure

“…Such methodologies thereby facilitate the sampling of both miracidial and cercarial populations in the field, thus avoiding the introduction of sampling bias through the loss of alleles or genotypes by sampling error or host-induced selection in the subsequent population genetic analyses [14], [16]–[19].…”

Experimental models of Schistosoma mansoni infection

“…a higher proportion of eggs in the liver) in mice (Anderson & Cheever 1972) and a different pattern in monkeys (Powers & Cheever 1972). Rapid changes in isoenzyme patterns occur during successive generations of newly isolated S. mansoni strains in mice so that it is clear that genetic selection may occur rapidly in the laboratory (LoVerde et al 1985, Bremond et al 1993. Pinto et al (1997) recently documented the greater genetic variability in worms from field isolates compared to the LE strain long maintained in the laboratory.…”

Host Mouse Strain Is Not Selective for a Laboratory Adapted Strain of Schistosoma mansoni

“…Some mammals, such as foxes and rabbits, are absolutely resistant (Von Lichtenberg et al, 1962; Peck et al, 1983), while others demonstrate selection of certain S. mansoni genotypes (LoVerde et al, 1985; Bremond et al, 1993). Although rats of the species Rattus rattus can maintain the life cycle, R. norvegicus cannot (Alarcón de Noya et al, 1997).…”

“…Previous studies have reported selection for particular S. mansoni alloenzyme alleles when S. mansoni populations from baboons (LoVerde et al, 1985) and rats (Bremond et al, 1993) were maintained in laboratory mice. Since at least one of the allozymes selected against may be antigenic in mice and provoke an immune response (Bremond et al, 1993), these studies are not directly relevant to our work with neutral markers.…”

“…Since at least one of the allozymes selected against may be antigenic in mice and provoke an immune response (Bremond et al, 1993), these studies are not directly relevant to our work with neutral markers. Laboratory mice and rabbits were reported to select for different microsatellite alleles when a field population of S. japonicum was transferred into the two species (Shrivastava et al, 2005) based on the number of private alleles found in the mouse and rabbit derived subpopulations, although repeated selection for those same alleles was not demonstrated.…”