title: Divergent Effects ofSchistosoma haematobiumExposure on Intermediate-Host Snail SpeciesBulinus nasutusandBulinus globosusfrom Coastal Kenya.
abstract: AbstractSchistosoma haematobiuminfection causes urogenital schistosomiasis, a chronic inflammatory disease that is highly prevalent in many parts of sub-Saharan Africa. Bulinid snails are the obligate intermediate hosts in the transmission of this parasite. In the present study,Bulinus globosusandBulinus nasutussnails from coastal Kenya were raised in the laboratory and exposed to miracidia derived from sympatricS. haematobiumspecimens to assess the species-specific impact of parasite contact and infection. The snails' subsequent patterns of survival, cercarial shedding, and reproduction were monitored for up to 3 months postexposure.Schistosoma haematobiumexposure significantly decreased the survival ofB. globosus, but not ofB. nasutus. Although both species were capable of transmittingS. haematobium, theB. globosusstudy population had a greater cumulative incidence of cercarial shedders and a higher average number of cercariae shed per snail than did theB. nasutuspopulation. The effects of prior parasite exposure on snail reproduction were different between the two species. These included more numerous production of egg masses by exposedB. nasutus(as compared with unexposed snails), contrasted to decreased overall egg mass production by parasite-exposedB. globosus. The interspecies differences in the response to and transmission ofS. haematobiumreflect clear differences in life histories for the two bulinid species when they interact with the parasite, which should be taken into account when planning control interventions aimed at reducing each host snails' contribution to local transmission ofSchistosomainfection.
authors.affiliation: Division of Vector Borne Diseases, Ministry of Health, Nairobi, Kenya.
authors.forename: H Curtis
authors.initials: HC
authors.lastname: Kariuki
authors.affiliation: Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio.
authors.forename: Julianne A
authors.initials: JA
authors.lastname: Ivy
authors.affiliation: Division of Vector Borne Diseases, Ministry of Health, Nairobi, Kenya.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Muchiri
authors.affiliation: Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Sutherland
authors.affiliation: Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio.
authors.forename: Charles H
authors.initials: CH
authors.lastname: King
mesh_terms: D000818:Animals; D002033:Bulinus / Q000469:parasitology*; D058487:Cercaria; D006790:Host-Parasite Interactions; D007630:Kenya; D012548:Schistosoma haematobium / Q000502:physiology*; D013045:Species Specificity