Objective

1. THE MACRO- AND MICROEPIDEMIOLOGY OF SOIL-TRANSMITTED HELMINTHS (STH) IN PRE-SCHOOL CHILDREN OF ZANZIBAR: TOWARDS INTEGRATING THE YOUNGER CHILD IN CONTROL INITIATIVES Sousa-Figueiredo J.C.1, Imison E.2, French M.D.3, Khamis I.S.4, Basáñez M.-G.3, Rollinson D.1, Stothard J.R.1 1 Department of Zoology, Natural History Museum, London, United Kingdom; 2 London School of Hygiene and Tropical Medicine, London, United Kingdom; 3 Department of Infectious Disease Epidemiology, Imperial College, London, United Kingdom; 4 Helminth Control Laboratory Unguja, Zanzibar, Tanzania. Objective Determine the impact of STH on pre-school children (aged <6 years) in Zanzibar: macro- and microepidemiological dynamics A mother being provided with sterilized containers A mother and her children: the real impact of household transmission of STH Treatment of the younger child. Image from the WHO’s Action Against Worms newsletter Concluding Remarks • Need to further understand the role of pre-school children in the overall epidemiology of STHs • Calling inclusion of this younger group, as they are at a high risk before reaching school-age • Improve targeting of STH campaigns: transmission dynamics are not homogeneous • METHODOLOGY • Two surveys were conducted on Zanzibar Island: • 112 pre-school children from four hamlets spanning a total area of ~30km2 (Chaani area) • 318 pre-school children from ten hamlets across the whole island (~1,460km2) SOIL-TRANSMITTED HELMINTHIASIS AND THE YOUNGER CHILD Current initiatives for the control of STH are commonly based upon the provision of chemotherapy to schoolchildren (>5 year olds) aiming to reduce infection intensity and prevalence, as well as preventing development of morbidity. New insights, however, reveal that children as young as one year old can be highly affected by these parasites. • WHO RECOMMENDATIONS • Drug dosage:Albendazole (400mg) – ½ tablet for 1-2 years, and one tablet for >2 years; Mebendazole (500mg) – one tablet for all ages • Staff training and supervision during administration • Crush tablets and use water • The mother has a pivotal role in calming the child • Never force the child to swallow the mixture Key Findings • Pre-school children were found to be susceptible to soil-transmitted helminthiasis (STHs) [prevalence = 19.3%, 95% confidence intervals (CI95) 15.1 – 21.1], particularly those residing in hamlets around Chaani village (50.0%, CI95 40.7 – 59.3%) • Prevalence (and CI95) of individual STH at both the macro- (island-wide) and microepidemiological (Chaani area) levels were, respectively: • Ascaris lumbricoides 7.5% (4.8-10.9%) and 32.1% (23.6-41.6%) • Trichuris trichiura and 17.5% (13.5-22.1%) and 38.4% (29.4-48.1%) • Hookworm 1.6% (0.5-3.6%) and 0.9% (0.1-4.9%) • STH were found to be associated with (univariate analysis): • Age (OR=1.35 per additional year, P<0.01) • Having access to a household latrine (OR=0.38, P<0.01) • Wearing shoes (OR=0.46, P=0.019) • To the child’s mother being infected herself (OR=6.59, P<0.001) • References: • Action Against Worms newsletter, February 2007, Issue 8, World Health Organization • Sousa-Figueiredo JC, Basanez M-G, Mgeni AF, Khamis IS, Rollinson D and Stothard JR (2008). A parasitological survey of preschool children and their mothers for urinary schistosomiasis, soil-transmitted helminthiasis and malaria in rural Zanzibar, with observations on prevalence of anaemia. Annals of Tropical Medicine and Parasitology (in the Press) • Stothard JR, Imison E, French MD, Sousa-Figueiredo JC, Khamis IS and Rollinson D (2008). Soil-transmitted helminthiasis (STH) among mothers and their pre-school children on Unguja Island, Zanzibar, with emphasis upon ascariasis. Parasitology (2008), 135, 1–9 • Acknowledgements: Zanzibar MoHSW; Schistosomiasis Control Initiative, UK; the African Development Bank, Tanzania; and The Health Foundation, UK.