03232nas a2200409 4500000000100000008004100001653002400042653001700066653002000083653002400103653002800127653001500155653000900170653003500179653002400214653001100238653001400249653001800263653001400281653001100295653001000306653001200316653001500328100001300343700002300356700001100379700001300390700001300403700001800416700001200434245014200446856009000588300001000678490000600688520211400694022001402808 2012 d10aTopography, Medical10aSierra Leone10aschistosomiasis10aSchistosoma mansoni10aSchistosoma haematobium10aPrevalence10aMale10aIntestinal Diseases, Parasitic10aIntestinal Diseases10aHumans10aHelminths10aHelminthiasis10aGeography10aFemale10aChild10aAnimals10aAdolescent1 aHodges M1 aSoares Magalhaes R1 aPaye J1 aKoroma J1 aSonnie M1 aClements AC A1 aZhang Y00aCombined spatial prediction of schistosomiasis and soil-transmitted helminthiasis in Sierra Leone: a tool for integrated disease control. uhttp://journals.plos.org/plosntds/article/asset?id=10.1371%2Fjournal.pntd.0001694.PDF ae16940 v63 a

BACKGROUND: A national mapping of Schistosoma haematobium was conducted in Sierra Leone before the mass drug administration (MDA) with praziquantel. Together with the separate mapping of S. mansoni and soil-transmitted helminths, the national control programme was able to plan the MDA strategies according to the World Health Organization guidelines for preventive chemotherapy for these diseases.

METHODOLOGY/PRINCIPAL FINDINGS: A total of 52 sites/schools were selected according to prior knowledge of S. haematobium endemicity taking into account a good spatial coverage within each district, and a total of 2293 children aged 9-14 years were examined. Spatial analysis showed that S. haematobium is heterogeneously distributed in the country with significant spatial clustering in the central and eastern regions of the country, most prevalent in Bo (24.6% and 8.79 eggs/10 ml), Koinadugu (20.4% and 3.53 eggs/10 ml) and Kono (25.3% and 7.91 eggs/10 ml) districts. By combining this map with the previously reported maps on intestinal schistosomiasis using a simple probabilistic model, the combined schistosomiasis prevalence map highlights the presence of high-risk communities in an extensive area in the northeastern half of the country. By further combining the hookworm prevalence map, the at-risk population of school-age children requiring integrated schistosomiasis/soil-transmitted helminth treatment regimens according to the coendemicity was estimated.

CONCLUSIONS/SIGNIFICANCE: The first comprehensive national mapping of urogenital schistosomiasis in Sierra Leone was conducted. Using a new method for calculating the combined prevalence of schistosomiasis using estimates from two separate surveys, we provided a robust coendemicity mapping for overall urogenital and intestinal schistosomiasis. We also produced a coendemicity map of schistosomiasis and hookworm. These coendemicity maps can be used to guide the decision making for MDA strategies in combination with the local knowledge and programme needs.

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