Volume 85, Issue 6
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



We analyzed temporal changes in spatial patterns of active infection in different age groups and associated them with ponds infested with snails. A major drought between 2001 and 2009 resulted in drying of ponds that were known sources of infection, and we detected very few or no snails in ponds that were infested in the past. The household-level spatial pattern of infection for children of various age groups in 2009 was contrasted with historical data from 2000. The significant local clustering of high- and low-infection levels among school-aged children that occurred in 2000 was absent in 2009. We attribute the disappearance of significant clustering around historical transmission hot spots to a decade-long drought in our study area. The implications of extreme weather and climate conditions on risk and transmission of and their relevance to control strategies are discussed.


Article metrics loading...

The graphs shown below represent data from March 2017
Loading full text...

Full text loading...



  1. Chitsulo O, Engels D, Montresor A, Savioli L, , 2000. The global status of schistosomiasis and its control. Acta Trop 77: 4151.[Crossref] [Google Scholar]
  2. Stothard JR, Chitsulo O, Kristensen TK, Utzinger J, , 2009. Control of schistosomiasis in sub-Saharan Africa: progress made, new opportunities and remaining challenges. Parasitology 136: 16651675.[Crossref] [Google Scholar]
  3. van der Werf MJ, de Vlas SJ, Brooker S, Looman CW, Nagelkerke NJ, Habbema JD, Engels D, , 2003. Quantification of clinical morbidity associated with schistosome infection in sub-Saharan Africa. Acta Trop 86: 125139.[Crossref] [Google Scholar]
  4. World Health Organization, 2002. Prevention and Control of Schistosomiasis and Soil Transmitted Helminthiasis: Report of a WHO Expert Committee. World Health Organ Technical Report Series 912. Geneva, Switzerland: World Health Organization, 25. [Google Scholar]
  5. Clennon JA, Mungai P, Muchiri EM, King CH, Kitron U, , 2006. Spatial and temporal variations in local transmission of Schistosoma haematobium in Msambweni, Kenya. Am J Trop Med Hyg 75: 10341041. [Google Scholar]
  6. Rudge JW, Stothard JR, Basáñez M, Mgeni AF, Khamis IS, Khamis AN, Rollinson D, , 2008. Micro-epidemiology of urinary schistosomiasis in Zanzibar: local risk factors associated with distribution of infections among schoolchildren and relevance for control. Acta Trop 105: 4554.[Crossref] [Google Scholar]
  7. Satayathum SA, Muchiri EM, Ouma JH, Whalen CC, King CH, , 2006. Factors affecting infection or reinfection with Schistosoma haematobium in coastal Kenya: survival analysis during a nine-year, school-based treatment program. Am J Trop Med Hyg 75: 8392. [Google Scholar]
  8. King CH, , 2006. Long-term outcomes of school-based treatment for control of urinary schistosomiasis: a review of experience in Coast Province, Kenya. Mem Inst Oswaldo Cruz 101: 299306.[Crossref] [Google Scholar]
  9. King CH, Muchiri EM, Ouma JH, Koech D, , 1991. Chemotherapy-based control of schistosomiasis haematobia. IV. Impact of repeated annual chemotherapy on prevalence and intensity of Schistosoma haematobium infection in an endemic area of Kenya. Am J Trop Med Hyg 45: 498508. [Google Scholar]
  10. Muchiri EM, Ouma J, King CH, , 1996. Dynamics and control of Schistosoma haematobium transmission in Kenya: an overview of the Msambweni project. Am J Trop Med Hyg 55: 127134. [Google Scholar]
  11. Sturrock RF, Kinyanjui H, Thiongo FW, Tosha S, Ouma JH, King CH, Koech D, Siongok TK, Mahmoud AAF, , 1990. Chemotherapy-based control of schistosomiasis haematobia. 3. Snail studies monitoring the effect of chemotherapy on transmission in the Msambweni area, Kenya. Trans R Soc Trop Med Hyg 84: 257261.[Crossref] [Google Scholar]
  12. Kariuki HC, Clennon JA, Brady MS, Kitron U, Sturrock RF, Ouma JH, Ndzovu M, 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]
  13. Clennon JA, King CH, Muchiri EM, Kariuki HC, Ouma JH, Mungai P, Kitron U, , 2004. Spatial patterns of urinary schistosomiasis infection in a highly endemic area of coastal Kenya. Am J Trop Med Hyg 70: 443444. [Google Scholar]
  14. el Kholy H, Siongok TK, Koech D, Sturrock RF, Houser H, King CH, Mahmoud AAF, , 1989. Effects of borehole wells on water utilization in Schistosoma haematobium endemic communities in Coast province, Kenya. Am J Trop Med Hyg 41: 212219. [Google Scholar]
  15. Ouma JH, Sturrock RF, Klumpp RK, Kariuki HC, , 1989. A comparative evaluation of snail sampling and cercariometry to detect Schistosoma mansoni transmission in a large-scale, longitudinal field-study in Machakos, Kenya. Parasitology 99: 349355.[Crossref] [Google Scholar]
  16. Peters PAS, Kazura JW, Maa F, , 1987. Update on diagnostic methods for schistosomiasis. , ed. Balliere's Clinical Tropical Medicine and Communicable Diseases, Schistosomiasis. London, United Kingdom: Bailliere Tindall, 419433. [Google Scholar]
  17. Kitron UD, Higashi GI, , 1985. Schistosoma haematobium in Upper Egypt: analysis of dispersion patterns. Am J Trop Med Hyg 34: 331340. [Google Scholar]
  18. King CH, Lombardi G, Lombardi C, Greenblatt R, Hodder S, Kinyanjui H, Ouma J, Odiambo O, Bryan PJ, Muruka J, , 1988. Chemotherapy-based control of schistosomiasis haematobia. I. Metrifonate versus praziquantel in control of intensity and prevalence of infection. Am J Trop Med Hyg 39: 295305. [Google Scholar]
  19. Ripley BD, , 1976. The second-order analysis of stationary point processes. J Appl Probab 13: 255266.[Crossref] [Google Scholar]
  20. Getis A, , 1984. Interaction modeling using second-order analysis. Environ Plan A 16: 173183.[Crossref] [Google Scholar]
  21. Getis A, Morrison AC, Gray K, Scott TW, , 2003. Characteristics of the spatial pattern of the dengue vector, Aedes aegypti, in Iquitos, Peru. Am J Trop Med Hyg 69: 494505. [Google Scholar]
  22. Getis A, Ord JK, , 1992. The analysis of spatial association by use of distance statistics. Geogr Anal 24: 189206.[Crossref] [Google Scholar]
  23. Getis A, Ord JK, , 1995. Local spatial autocorrelation statistics: distributional issues and an application. Geogr Anal 27: 286306. [Google Scholar]
  24. Ord JK, Getis A, Longley P, Batty M, , 1996. Local spatial statistics: an overview. , eds. Spatial Analysis: Modeling in a GIS Environment. Cambridge, United Kingdom: Geoinformation International, 261277. [Google Scholar]
  25. Chen D, Getis A, , 1998. Point Pattern Analysis. San Diego, CA: Department of Geography, San Diego State University. [Google Scholar]
  26. Webbe G, , 1962. The transmission of Schistosoma haematobium in an area of Lake Province, Tanganyika. Bull World Health Organ 27: 5985. [Google Scholar]
  27. Williams GB, , 1907. The rainfall of the British East Africa Protectorate. Geogr J 29: 654660.[Crossref] [Google Scholar]
  28. Zein AZ, , 1989. Spontaneous reduction in Schistosoma mansoni infection in endemic communities of the lake Tana basin, north-western Ethiopia. Trans R Soc Trop Med Hyg 83: 656658.[Crossref] [Google Scholar]
  29. Pugh RNH, Gilles HM, , 1978. Malumfashi endemic diseases project. III. Urinary schistosomiasis: a longitudinal study. Ann Trop Med Parasitol 72: 471482.[Crossref] [Google Scholar]
  30. Chandiwana SK, Makaza D, Taputaira A, , 1987. Variations in the incidence of schistosomiasis in the highveld regions of Zimbabwe. Trop Med Parasitol 39: 313319. [Google Scholar]
  31. 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: S245S260. [Google Scholar]
  32. Clennon JA, King CH, Muchiri EM, Kitron U, , 2007. Hydrological modelling of snail dispersal patterns in Msambweni, Kenya and potential resurgence of Schistosoma haematobium transmission. Parasitology 134: 683693.[Crossref] [Google Scholar]

Data & Media loading...

  • Received : 29 Mar 2011
  • Accepted : 30 Aug 2011
  • Published online : 01 Dec 2011

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error