Volume 96, Issue 4
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



infection 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, and snails from coastal Kenya were raised in the laboratory and exposed to miracidia derived from sympatric specimens 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. exposure significantly decreased the survival of , but not of . Although both species were capable of transmitting , the study population had a greater cumulative incidence of cercarial shedders and a higher average number of cercariae shed per snail than did the population. The effects of prior parasite exposure on snail reproduction were different between the two species. These included more numerous production of egg masses by exposed (as compared with unexposed snails), contrasted to decreased overall egg mass production by parasite-exposed . The interspecies differences in the response to and transmission of reflect 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 of infection.


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  1. Dent A, King CH, , 2007. Schistosoma haematobium: the urinary parasite. Infect Med 24: 489496. [Google Scholar]
  2. Colley DG, Bustinduy AL, Secor WE, King CH, , 2014. Human schistosomiasis. Lancet 383: 22532264.[Crossref] [Google Scholar]
  3. Rozendaal JA, , 1997. Vector Control: Methods for Use by Individuals and Communities. Geneva, Switzerland: World Health Organization. [Google Scholar]
  4. Kariuki HC, Clennon JA, Brady MS, Kitron U, Sturrock RF, Ouma JH, Ndzovu ST, Mungai P, Hoffman O, Hamburger J, Pellegrini C, Muchiri EM, King CH, , 2004. Distribution patterns and cercarial shedding of Bulinus nasutus and other snails in the Msambweni area, Coast Province, Kenya. Am J Trop Med Hyg 70: 449456. [Google Scholar]
  5. O'Keefe JH, , 1985. Population biology of the freshwater snail Bulinus globosus on the Kenya coast: I. Population fluctuations in relation to climate. J Appl Ecol 22: 7384.[Crossref] [Google Scholar]
  6. Woolhouse ME, Chandiwana SK, , 1990. Population biology of the freshwater snail Bulinus globosus in the Zimbabwe highveld. J Appl Ecol 27: 4159.[Crossref] [Google Scholar]
  7. Anderson RM, May RM, , 1979. Prevalence of schistosome infections within molluscan populations: observed patterns and theoretical predictions. Parasitology 79: 6394.[Crossref] [Google Scholar]
  8. Stothard IR, Rollinson D, , 1997. Molecular characterization of Bulinus globosus and B. nasutus on Zanzibar, and an investigation of their roles in the epidemiology of Schistosoma haematobium . Trans R Soc Trop Med Hyg 91: 353357.[Crossref] [Google Scholar]
  9. Stothard JR, Loxton N, Rollinson D, Mgeni AF, Khamis S, Ameri H, Ramsan M, Savioli L, , 2000. The transmission status of Bulinus on Zanzibar Island (Unguja), with implications for control of urinary schistosomiasis. Ann Trop Med Parasitol 94: 8794.[Crossref] [Google Scholar]
  10. Stothard JR, Mgeni AF, Khamis S, Seto E, Ramsan M, Hubbard SJ, Kristensen TK, Rollinson D, , 2002. New insights into the transmission biology of urinary schistosomiasis in Zanzibar. Trans R Soc Trop Med Hyg 96: 470475.[Crossref] [Google Scholar]
  11. Fryer SE, Oswald RC, Probert AJ, Runham NW, , 1990. The effect of Schistosoma haematobium infection on the growth and fecundity of three sympatric species of bulinid snails. J Parasitol 76: 557563.[Crossref] [Google Scholar]
  12. Blair L, Webster JP, , 2007. Dose-dependent schistosome-induced mortality and morbidity risk elevates host reproductive effort. J Evol Biol 20: 5461.[Crossref] [Google Scholar]
  13. Hamburger J, Hoffman O, Kariuki HC, Muchiri EM, Ouma JH, Koech DK, Sturrock RF, King CH, , 2004. Large-scale, polymerase chain reaction-based surveillance of Schistosoma haematobium DNA in snails from transmission sites in coastal Kenya: a new tool for studying the dynamics of snail infection. Am J Trop Med Hyg 71: 765773. [Google Scholar]
  14. WHO Snail Identification Centre, 1973. Field Guide to the East African Species. Copenhagen, Denmark: Danish Bilharzia Laboratory. [Google Scholar]
  15. Rollinson D, Stothard JR, Southgate VR, , 2001. Interactions between intermediate snail hosts of the genus Bulinus and schistosomes of the Schistosoma haematobium group. Parasitology 123 (Suppl): S245S260. [Google Scholar]
  16. King CH, Blanton RE, Muchiri EM, Ouma JH, Kariuki HC, Mungai P, Magak P, Kadzo H, Ireri E, Koech D, , 2004. Low heritable component of risk for infection intensity and infection-associated disease in urinary schistosomiasis among Wadigo village populations in Coast Province, Kenya. Am J Trop Med Hyg 70: 5762. [Google Scholar]
  17. Pringle G, Otieno LH, Chimtawi MB, , 1971. Notes on the morphology, susceptibility to Schistosoma haematobium and genetic relationships of Bulinus (Physopsis) globosus globosus and B. (P.) nasutus nasutus from north-eastern Tanzania. Ann Trop Med Parasitol 65: 211219.[Crossref] [Google Scholar]
  18. Webbe G, Msangi AS, , 1958. Observations on three species of Bulinus on the east coast of Africa. Ann Trop Med Parasitol 52: 302314.[Crossref] [Google Scholar]
  19. Barlow CH, Muench H, , 1951. Life span and monthly mortality rate of Bulinus truncatus and Planorbis biossyi, the intermediate hosts of schistosomiasis in Egypt. J Parasitol 37: 165173.[Crossref] [Google Scholar]
  20. McClelland WF, , 1964. A method of breeding Bulinus (Physopsis) nasutus in the laboratory. Ann Trop Med Parasitol 58: 265269.[Crossref] [Google Scholar]
  21. Thomas JD, , 1973. Schistosomiasis and control of molluscan hosts of human schistosomes with particular reference to possible self-regulatory mechanisms. Adv Parasitol 11: 307394.[Crossref] [Google Scholar]
  22. World Health Organization, 2013. Schistosomiasis: Progress Report 2001–2011, Strategic Plan 2012–2020. Geneva, Switzerland: World Health Organization, 81. [Google Scholar]
  23. Gurarie D, Yoon N, Li E, Ndeffo-Mbah M, Durham D, Phillips AE, Aurelio HO, Ferro J, Galvani AP, King CH, , 2015. Modelling control of Schistosoma haematobium infection: predictions of the long-term impact of mass drug administration in Africa. Parasit Vectors 8: 529.[Crossref] [Google Scholar]

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  • Received : 28 Jul 2016
  • Accepted : 14 Dec 2016
  • Published online : 23 Jan 2017

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