Cercarial Chaetotaxy and Sex Differentiation of Schistosoma mansoni Deriving from Humans and Nectomys squamipes (Muridae: Sigmondontinae) in Brazil

A comparative parasitologic study on Biomphalaria glabrata snail and C3H/He mice infected with human and murine isolates of Schistosoma mansoni derived from Sumidouro, Rio de Janeiro, Brazil

“…Of particular relevance is the fact that both isolates share phenotypic characteristics (Machado-Silva et al 1994, Neves et al 1998, Freire et al 2002. This observation is coherent with the results obtained with sympatric isolates from Guadeloupe and Senegal when a biochemical marker (isoenzymes profile) was used (Sène et al 1997).…”

“…It is perhaps relevant to mention that our data provide support to the hypothesis that in a same biotope, mixed populations or sub-populations circulate among their main host (human or rodent) that act as a biological filter (Freire et al 2002). As genetic differentiation within infrapopulations in rodents has been found (Sire et al 2001), DNA microsatellite markers could be used to investigate the genetic structuring of natural populations (Durand et al 2000.…”

“…Given that digenetic trematodes are primitively snail parasites and not of vertebrates perhaps their role as a biological filter is more efficient than vertebrate hosts (Freire et al 2002).…”

“…Infection-free snails (n = 100) were used as a control group. The snails were kept in glass vials with dechlorinated tap water and fed fresh lettuce (Lacttuca sativa) ad libitum (Freire et al 2002).…”

“…Recently, it was demonstrated that cercariae deriving from sympatric murine and human isolates display only slight differences (Freire et al 2002). Further studies of the parasitological characteristics of both sympatric isolates and epidemiological implications are presented and discussed.…”