Skip to main content
Article thumbnail
Location of Repository

Parasitological impact of 2-year preventive chemotherapy on schistosomiasis and soil-transmitted helminthiasis in Uganda

By Yaobi Zhang, Artemis Koukounari, Narcis Kabatereine, Fiona Fleming, Francis Kazibwe, Edridah Tukahebwa, J Russell Stothard, Joanne P. Webster and Alan Fenwick


Background Schistosomiasis and soil-transmitted helminthiasis (STH) are among the neglected tropical diseases in Africa. A national control program for these diseases was initiated in Uganda during March 2003. Annual treatment with praziquantel and albendazole was given to schoolchildren in endemic areas and to adults in selected communities where local prevalence of Schistosoma mansoni in schoolchildren was high. Methods The impact of the treatment program was monitored through cohorts of schoolchildren and adults. Their infection status with S. mansoni and STH was determined by parasitological examinations at baseline and at annual follow-ups. The prevalence and intensity of S. mansoni and STH before and after treatment were analyzed. Results Two rounds of treatment significantly reduced the prevalence of S. mansoni infection in schoolchildren across three regions in the country from 33.4–49.3% to 9.7–29.6%, and intensity of infection from 105.7–386.8 eggs per gram of faeces (epg) to 11.6–84.1 epg. The prevalence of hookworm infection was reduced from 41.2–57.9% to 5.5–16.1%, and intensity of infection from 186.9–416.8 epg to 3.7–36.9 epg. The proportion of children with heavy S. mansoni infection was significantly reduced from 15% (95% CI 13.4–16.8%) to 2.3% (95% CI 1.6–3.0%). In adults, significant reduction in the prevalence and intensity of S. mansoni and hookworm infections was also observed. More importantly, the prevalence and intensity of both S. mansoni and hookworm infections in the cohorts of newly-recruited 6-year-olds who had never previously received treatment decreased significantly over 2 years: 34.9% (95% CI 31.9–37.8%) to 22.6% (95% CI 19.9–25.2%) and 171.1 epg (95% CI 141.5–200.7) to 72.0 epg (95% CI 50.9–93.1) for S. mansoni; and 48.4% (95% CI 45.4–51.5) to 15.9% (95% CI 13.6–18.2) and 232.7 epg (95% CI 188.4–276.9) to 51.4 epg (95% CI 33.4–69.5) for hookworms, suggesting a general decline in environmental transmission levels. Conclusion Annual anthelminthic treatment delivered to schoolchildren and to adults at high risk in Uganda can significantly reduce the prevalence and intensity of infection for schistosomiasis and STH, and potentially also significantly reduce levels of environmental transmission of infection

Topics: DT Africa, RA Public aspects of medicine
Publisher: BioMed Central
Year: 2007
DOI identifier: 10.1186/1741-7015-5-27
OAI identifier:
Provided by: LSE Research Online

Suggested articles


  1. (1972). A simple device for quantitative stool thick-smear technique in Schistosomiasis mansoni. Rev Inst Med Trop Sao Paulo
  2. (2001). A: Epidemiology of intestinal helminth infestations among schoolchildren in southern Uganda. East Afr Med J doi
  3. (2006). A: Morbidity due to Schistosoma mansoni: an epidemiological assessment of distended abdomen syndrome in Ugandan school children with observations before and 1-year after anthelminthic chemotherapy. Trans R Soc Trop Med Hyg doi
  4. (2004). Appleton CC: Patterns of geohelminth infection, impact of albendazole treatment and reinfection after treatment in schoolchildren from rural KwaZulu-Natal/South-Africa. BMC Infect Dis
  5. (2005). CH: Heterogeneous model of schistosomiasis transmission and long-term control: the combined influence of spatial variation and age-dependent factors on optimal allocation of drug therapy. Parasitology doi
  6. (1994). Dispersion and bias: can we trust geometric means? Parasitol Today doi
  7. (1999). Doehring E: Evidence for a long-term effect of a single dose of praziquantel on Schistosoma mansoni-induced hepatosplenic lesions in northern Uganda. Am J Trop Med Hyg
  8. (2003). E: The burden of chronic disease. Science doi
  9. (2004). et al.: Hepatosplenic morbidity in two neighbouring communities in Uganda with high levels of Schistosoma mansoni infection but very different durations of residence. Trans R Soc Trop Med Hyg doi
  10. (2006). et al.: Progress towards countrywide control of schistosomiasis and soil-transmitted helminthiasis in Uganda. Trans R Soc Trop Med Hyg doi
  11. (2007). Fenwick A: Impact of a national helminth control programme on infection and morbidity in Ugandan schoolchildren. Bull World Health Organ
  12. (2004). Fincham JE: Efficacy of albendazole against the whipworm Trichuris trichiura – a randomised, controlled trial.
  13. (2005). GF: Vaccine-linked chemotherapy: can schistosomiasis control benefit from an integrated approach? Trends Parasitol doi
  14. (2006). Hotez PJ: Soil-transmitted helminth infections: ascariasis, trichuriasis, and hookworm. Lancet doi
  15. (2006). JP: Morbidity indicators of Schistosoma mansoni: relationship between infection and anemia in Ugandan schoolchildren before and after praziquantel and albendazole chemotherapy. Am J Trop Med Hyg
  16. (2004). Kazibwe F: Spatial analysis of the distribution of intestinal nematode infections in Uganda. Epidemiol Infect doi
  17. (2004). Medhin G: Comparative efficacy of albendazole and three brands of mebendazole in the treatment of ascariasis and trichuriasis. East Afr Med J doi
  18. (2003). MH: Drugs for the control of parasitic diseases: current status and development in schistosomiasis. Trends Parasitol doi
  19. Odongo-Aginya EI, Lakwo TL: Schistosoma mansoni along Lake Albert, Kibale District, doi
  20. (2004). Onapa AW: Epidemiology and geography of Schistosoma mansoni in Uganda: implications for planning control. Trop Med Int Health doi
  21. (2002). Organisation: Prevention and control of schistosomiasis and soil-transmitted helminthiasis.
  22. Organisation: World Health Report 2004: Changing History. doi
  23. (2003). Quantification of clinical morbidity associated with schistosome infection in sub-Saharan Africa. Acta Trop doi
  24. (2005). S: Epidemiology of helminth infections and their relationship to clinical malaria in southwest Uganda. Trans R Soc Trop Med Hyg doi
  25. (2005). S: Short communication: soil-transmitted helminthiasis in Uganda: epidemiology and cost of control. Trop Med Int Health doi
  26. (2006). Sachs JD: Incorporating a rapid-impact package for neglected tropical diseases with programs for HIV/AIDS, tuberculosis, and malaria. PLoS Med doi
  27. (2003). Savioli L: Soil-transmitted helminth infections: updating the global picture. Trends Parasitol doi
  28. (2002). Savioli L: The global epidemiological situation of schistosomiasis and new approaches to control and research. Acta Trop doi
  29. (2000). Savioli L: The global status of schistosomiasis and its control. Acta Trop doi
  30. Schistosoma mansoni in Pachwach,
  31. (1958). Schistosoma mansoni infection in the West Nile District of Uganda. I. The incidence of S. mansoni infection. East Afr Med J
  32. (1958). Schistosoma mansoni infection in the West Nile district of Uganda. II. The distribution of S. mansoni with a note on the probable vectors. East Afr Med J
  33. (2004). Schistosomiasis and soil-transmitted helminthiasis: common drugs for treatment and control. Expert Opin Pharmacother doi
  34. (2006). Schistosomiasis and water resources development: systematic review, metaanalysis, and estimates of people at risk. Lancet Infect Dis doi
  35. (2002). Schistosomiasis: from risk assessment to control. Trends Parasitol doi
  36. (2005). ST: Helminth infection and cognitive impairment among Filipino children. Am J Trop Med Hyg
  37. (2005). ST: Human schistosomiasis and anemia: the relationship and potential mechanisms. Trends Parasitol doi
  38. (1997). The global burden of intestinal nematode infections – Fifty years on. Parasitol Today doi
  39. (2005). Tisch DJ: Reassessment of the cost of chronic helmintic infection: a meta-analysis of disabilityrelated outcomes in endemic schistosomiasis. Lancet doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.