Volume 81, Issue 6
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


Helminth control programs have been implemented in Zanzibar for over a decade. In June/July 2007, ~6 months after the last school-based anthelmintic treatment, a cross-sectional survey was carried out in two schools, and results were compared with data obtained in the same schools in 1994. Multiple stool samples collected from 368 school children were subjected to the Kato-Katz, Koga agar plate, and Baermann methods. The prevalence of , hookworm, and was 46.6%, 21.6%, 16.9%, and 10.2%, respectively. Infection intensities were generally low. Compared with 1994, the prevalence of , hookworm, and decreased by 81.0%, 80.5%, 70.6%, and 48.6%, respectively. Infection intensities decreased by > 95% for all helminth species studied. Our study confirms that preventive chemotherapy successfully reduces the level and intensity of helminth infections. To consolidate achievements made, additional control measures such as health education and environmental sanitation are needed.


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  1. Brooker S, Clements ACA, Bundy DAP, 2006. Global epidemiology, ecology and control of soil-transmitted helminth infections. Adv Parasitol 62: 221–261. [Google Scholar]
  2. Hotez PJ, Brindley PJ, Bethony JM, King CH, Pearce EJ, Jacobson J, 2008. Helminth infections: the great neglected tropical diseases. J Clin Invest 118: 1311–1321. [Google Scholar]
  3. Savioli L, Albonico M, Engels D, Montresor A, 2004. Progress in the prevention and control of schistosomiasis and soil-transmitted helminthiasis. Parasitol Int 53: 103–113. [Google Scholar]
  4. Keiser J, Utzinger J, 2008. Efficacy of current drugs against soil-transmitted helminth infections: systematic review and meta-analysis. JAMA 299: 1937–1948. [Google Scholar]
  5. Lancet-Editorial, 2004. Thinking beyond deworming. Lancet 364: 1993–1994. [Google Scholar]
  6. Worldbank, 2003. School Deworming at a Glance. Washington, DC: Worldbank.
  7. Albonico M, Chwaya H, Tielsch J, 1997. The burden of parasitic infection in school children of Zanzibar: a need for integrated control. East Afr Med J 74: 294–298. [Google Scholar]
  8. Marti HP, Haji HJ, Savioli L, Chwaya HM, Mgeni AF, Ameir JS, Hatz C, 1996. A comparative trial of a single-dose ivermectin versus three days of albendazole for treatment of Strongyloides stercoralis and other soil-transmitted helminth infections in children. Am J Trop Med Hyg 55: 477–481. [Google Scholar]
  9. Olsen A, van Lieshout L, Marti H, Polderman T, Polman K, Steinmann P, Stothard R, Thybo S, Verweij JJ, Magnussen P, 2009. Strongyloidiasis: the most neglected of the neglected tropical diseases? Trans R Soc Trop Med Hyg 103: 967–972. [Google Scholar]
  10. Montresor A, Ramsan M, Chwaya HM, Ameir H, Foum A, Albonico M, Gyorkos TW, Savioli L, 2001. School enrollment in Zanzibar linked to children’s age and helminth infections. Trop Med Int Health 6: 227–231. [Google Scholar]
  11. Renganathan E, Ercole E, Albonico M, De Gregorio G, Alawi KS, Kisumku UM, Savioli L, 1995. Evolution of operational research studies and development of a national control strategy against intestinal helminths in Pemba Island, 1988–92. Bull World Health Organ 73: 183–190. [Google Scholar]
  12. Stothard JR, Imison E, French MD, Sousa-Figueiredo JC, Khamis IS, Rollinson D, 2008. Soil-transmitted helminthiasis among mothers and their pre-school children on Unguja Island, Zanzibar with emphasis upon ascariasis. Parasitology 135: 1447–1455. [Google Scholar]
  13. Mohammed KA, Haji HJ, Gabrielli A, Mubila L, Biswas G, Chitsulo L, Bradley MH, Engels D, Savioli L, Molyneux DH, 2008. Triple co-administration of ivermectin, albendazole and praziquantel in Zanzibar: a safety study. PLoS Negl Trop Dis 2: e171. [Google Scholar]
  14. Stothard JR, Mook P, Mgeni AF, Khamis IS, Khamis AN, Rollinson D, 2006. Control of urinary schistosomiasis on Zanzibar (Unguja Island): a pilot evaluation of the educational impact of the Juma na Kichocho health booklet within primary schools. Mem Inst Oswaldo Cruz 101 (Suppl 1): 119–124. [Google Scholar]
  15. Stothard JR, French MD, Khamis IS, Basanez MG, Rollinson D, 2009. The epidemiology and control of urinary schistosomiasis and soil-transmitted helminthiasis in schoolchildren on Unguja Island, Zanzibar. Trans R Soc Trop Med Hyg 103: 1031–1044. [Google Scholar]
  16. WHO, 2001. Filariasis elimination, Zanzibar. Wkly Epidemiol Rec 76: 401–408. [Google Scholar]
  17. Mohammed KA, Molyneux DH, Albonico M, Rio F, 2006. Progress towards eliminating lymphatic filariasis in Zanzibar: a model programme. Trends Parasitol 22: 340–344. [Google Scholar]
  18. Zaha O, Hirata T, Kinjo F, Saito A, 2000. Strongyloidiasis—progress in diagnosis and treatment. Intern Med 39: 695–700. [Google Scholar]
  19. WHO, 2008. Soil-transmitted helminthiasis. Wkly Epidemiol Rec 83: 237–252. [Google Scholar]
  20. Fleiss J, 1981. The Measurement of Interrater Agreement. Statistical Methods for Rates and Proportions. New York: Wiley.
  21. Katz N, Chaves A, Pellegrino J, 1972. A simple device for quantitative stool thick-smear technique in schistosomiasis mansoni. Rev Inst Med Trop Sao Paulo 14: 397–400. [Google Scholar]
  22. Koga K, Kasuya S, Khamboonruang C, Sukhavat K, Ieda M, Takatsuka N, Kita K, Ohtomo H, 1991. A modified agar plate method for detection of Strongyloides stercoralis. Am J Trop Med Hyg 45: 518–521. [Google Scholar]
  23. García LS, Bruckner DA, 2001. Diagnostic Medical Parasitology. Washington, DC: American Society for Microbiology.
  24. Knopp S, Mgeni AF, Khamis IS, Steinmann P, Stothard JR, Rollinson D, Marti HP, Utzinger J, 2008. Diagnosis of soil-transmitted helminths in the era of preventive chemotherapy: effect of multiple stool sampling and use of different diagnostic techniques. PLoS Negl Trop Dis 2: e331. [Google Scholar]
  25. Marti HP, Koella JC, 1993. Multiple stool examinations for ova and parasites and rate of false-negative results. J Clin Microbiol 31: 3044–3045. [Google Scholar]
  26. Mullen K, Prost A, 1983. Decreased microfilarial load and its effect on the calculation of prevalence and the rate of false negatives in the detection of onchocerciasis. Int J Epidemiol 12: 102–104. [Google Scholar]
  27. Steinmann P, Zhou XN, Du ZW, Jiang JY, Wang LB, Wang XZ, Li LH, Marti H, Utzinger J, 2007. Occurrence of Strongyloides stercoralis in Yunnan province, China, and comparison of diagnostic methods. PLoS Negl Trop Dis 1: e75. [Google Scholar]
  28. Bogoch II, Raso G, N’Goran EK, Marti HP, Utzinger J, 2006. Differences in microscopic diagnosis of helminths and intestinal protozoa among diagnostic centres. Eur J Clin Microbiol Infect Dis 25: 344–347. [Google Scholar]
  29. Montresor A, Crompton DWT, Hall A, Bundy DAP, Savioli L, 1998. Guidelines for the Evaluation of Soil-Transmitted Helminthiasis and Schistosomiasis at Community Level. A Guide for Managers of Control Programmes. Geneva: World Health Organization.
  30. WHO, 2002. Prevention and control of schistosomiasis and soil-transmitted helminthiasis: report of an expert committee. WHO Tech Rep Ser 912: 1–57. [Google Scholar]
  31. Worldbank, 2006. Key Development Data and Statistics Tanzania. Washington, DC: Worldbank.
  32. Hall A, 1981. Quantitative variability of nematode egg counts in faeces: a study among rural Kenyans. Trans R Soc Trop Med Hyg 75: 682–687. [Google Scholar]
  33. Booth M, Vounatsou P, N’Goran EK, Tanner M, Utzinger J, 2003. The influence of sampling effort and the performance of the Kato-Katz technique in diagnosing Schistosoma mansoni and hookworm co-infections in rural Côte d’Ivoire. Parasitology 127: 525–531. [Google Scholar]
  34. Knopp S, Rinaldi L, Khamis IS, Stothard JR, Rollinson D, Maurelli MP, Steinmann P, Marti H, Cringoli G, Utzinger J, 2009. A single FLOTAC is more sensitive than triplicate Kato-Katz for the diagnosis of low-intensity soil-transmitted helminth infections. Trans R Soc Trop Med Hyg 103: 347–354. [Google Scholar]
  35. Stothard JR, Sousa-Figueiredo JC, Standley C, Van Dam GJ, Knopp S, Utzinger J, Ameri H, Khamis AN, Khamis IS, Deelder AM, Mohammed KA, Rollinson D, 2009. An evaluation of urine-CCA strip test and fingerprick blood SEA-ELISA for detection of urinary schistosomiasis in schoolchildren in Zanzibar. Acta Trop 111: 64–70. [Google Scholar]
  36. Bergquist R, Johansen MV, Utzinger J, 2009. Diagnostic dilemmas in helminthology: what tools to use and when? Trends Parasitol 25: 151–156. [Google Scholar]
  37. de Vlas SJ, Gryseels B, 1992. Underestimation of Schistosoma mansoni prevalences. Parasitol Today 8: 274–277. [Google Scholar]
  38. Utzinger J, Booth M, N’Goran EK, Müller I, Tanner M, Lengeler C, 2001. Relative contribution of day-to-day and intra-specimen variation in faecal egg counts of Schistosoma mansoni before and after treatment with praziquantel. Parasitology 122: 537–544. [Google Scholar]
  39. Steinmann P, Du ZW, Wang LB, Wang XZ, Jiang JY, Li LH, Marti H, Zhou XN, Utzinger J, 2008. Extensive multiparasitism in a village of Yunnan province, People’s Republic of China, revealed by a suite of diagnostic methods. Am J Trop Med Hyg 78: 760–769. [Google Scholar]
  40. Raso G, Utzinger J, Silue KD, Ouattara M, Yapi A, Toty A, Matthys B, Vounatsou P, Tanner M, N’Goran EK, 2005. Disparities in parasitic infections, perceived ill health and access to health care among poorer and less poor schoolchildren of rural Côte d’Ivoire. Trop Med Int Health 10: 42–57. [Google Scholar]
  41. Raso G, Vounatsou P, Gosoniu L, Tanner M, N’Goran EK, Utzinger J, 2006. Risk factors and spatial patterns of hookworm infection among schoolchildren in a rural area of western Côte d’Ivoire. Int J Parasitol 36: 201–210. [Google Scholar]
  42. de Silva NR, Brooker S, Hotez PJ, Montresor A, Engels D, Savioli L, 2003. Soil-transmitted helminth infections: updating the global picture. Trends Parasitol 19: 547–551. [Google Scholar]
  43. Brooker S, Bethony J, Hotez PJ, 2004. Human hookworm infection in the 21st century. Adv Parasitol 58: 197–288. [Google Scholar]
  44. Mabaso ML, Appleton CC, Hughes JC, Gouws E, 2003. The effect of soil type and climate on hookworm (Necator americanus) distribution in KwaZulu-Natal, South Africa. Trop Med Int Health 8: 722–727. [Google Scholar]
  45. Stoltzfus RJ, Chwaya HM, Tielsch JM, Schulze KJ, Albonico M, Savioli L, 1997. Epidemiology of iron deficiency anemia in Zanzibari schoolchildren: the importance of hookworms. Am J Clin Nutr 65: 153–159. [Google Scholar]
  46. Albonico M, Chwaya HM, Montresor A, Stolfzfus RJ, Tielsch JM, Alawi KS, Savioli L, 1997. Parasitic infections in Pemba Island school children. East Afr Med J 74: 294–298. [Google Scholar]
  47. Bradley M, Chandiwana SK, Bundy DAP, Medley GF, 1992. The epidemiology and population biology of Necator americanus infection in a rural community in Zimbabwe. Trans R Soc Trop Med Hyg 86: 73–76. [Google Scholar]
  48. Albonico M, Bickle Q, Ramsan M, Montresor A, Savioli L, Taylor M, 2003. Efficacy of mebendazole and levamisole alone or in combination against intestinal nematode infections after repeated targeted mebendazole treatment in Zanzibar. Bull World Health Organ 81: 343–352. [Google Scholar]
  49. Stothard JR, Rollinson D, Imison E, Khamis IS, 2009. A spot-check of the efficacies of albendazole or levamisole, against soil-transmitted helminthiases in young Ungujan children, reveals low frequencies of cure. Ann Trop Med Parasitol 103: 357–360. [Google Scholar]
  50. Olsen A, 2007. Efficacy and safety of drug combinations in the treatment of schistosomiasis, soil-transmitted helminthiasis, lymphatic filariasis and onchocerciasis. Trans R Soc Trop Med Hyg 101: 747–758. [Google Scholar]
  51. Ndyomugyenyi R, Kabatereine N, Olsen A, Magnussen P, 2008. Efficacy of ivermectin and albendazole alone and in combination for treatment of soil-transmitted helminths in pregnancy and adverse events: a randomized open label controlled intervention trial in Masindi district, western Uganda. Am J Trop Med Hyg 79: 856–863. [Google Scholar]
  52. Stothard JR, Mgeni AF, Khamis S, Seto E, Ramsan M, Rollinson D, 2002. Urinary schistosomiasis in schoolchildren on Zanzibar Island (Unguja), Tanzania: a parasitological survey supplemented with questionnaires. Trans R Soc Trop Med Hyg 96: 507–514. [Google Scholar]
  53. Hotez PJ, Feng Z, Xu LQ, Chen MG, Xiao SH, Liu SX, Blair D, McManus DP, Davis GM, 1997. Emerging and reemerging helminthiases and the public health of China. Emerg Infect Dis 3: 303–310. [Google Scholar]

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  • Received : 02 Jul 2009
  • Accepted : 11 Aug 2009

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