Background Schistosoma mansoni and Plasmodium falciparum are common infections of college aged children in Kenya. line (MAL). The survey was conducted outside the malaria transmission season. The consistency of the organ was recorded as soft firm or hard. Mapping of the locations of houses Vorinostat and the course of the river was undertaken. Egg counts were mapped at the household level as were IgG3 responses to Plasmodium falciparum schizont antigen (anti-Pfs IgG3) in order to identify areas with relatively high exposure to both infections either infection or neither infection. ANOVA was used to test for differences in egg counts IgG3 levels and the magnitude of spleen enlargement between these areas. Results 4 contiguous sectors were recognized one where anti-Pfs IgG3 responses and S. mansoni egg counts were both high one where only anti-Pfs IgG3 responses were high one where only egg counts were high and one where both anti-Pfs IgG3 responses and egg counts were low. Spleen MAL and MCL values were significantly higher amongst children from your sector with highest IgG3 levels and highest egg counts but comparable amongst children from elsewhere. Both egg counts and anti-Pfs IgG3 responses were significantly higher in children with MAL values >=4 cm. Hardening of spleens was associated with proximity of domicile to the river. Conclusions Micro-geographical variance in exposure to S. mansoni and malaria infections can be exploited to investigate the chronic impact of these two infections. These results provide firm evidence that relatively high exposure to both infections exacerbates splenomegaly even outside the malaria transmission season. Major implications include assessing the burden of Vorinostat contamination in school age-children. Keywords: S. mansoni malaria splenomegaly Kenya children GIS Background Contamination with multiple parasitic species is usually a common observation in parasitological surveys of communities in tropical and sub-tropical countries [1-3] but attempts to understand their combined health impact on affected individuals and communities have been very limited in both scope and number. An inherent problem is the lack of specificity of many signs and symptoms associated with parasitic contamination which can complicate attempts at attributing morbidity to a particular cause [4]. Hepatomegaly and splenomegaly fall into this category as common indicators amongst school-aged children in Africa with multiple aetiologies. Two of the most generally attributed causes are infections with Schistosoma mansoni and Plasmodium falciparum. It has long been suggested that the presence Vorinostat of one species may confound or change the effects of the other on the liver and spleen in endemic situations [5-7] but it has also been suggested that hepatosplenomegaly in infants is likely attributable to malaria contamination whereas amongst school-aged children it is more likely attributable to S. mansoni contamination [8]. This paradigm has prevailed in the absence of systematic research and Vorinostat the relative contribution of the two infections in the aetiology of chronic hepatosplenomegaly of school-aged children remains essentially unknown. Recent insights have been gained from a series of epidemiological and immunological studies in Kenya. In a cross-sectional study of children morbidity profiles were compared in two communities. After screening for the effect of several other infections only the prevalence of malaria was higher in the worst affected community an ecological observation that led to the recommendation that co-infection with malaria may exacerbate hepatosplenic CD96 morbidity connected with schistosome infections [9]. This hypothesis received support after retrospective assays and evaluation from the bloodstream samples in the same cohort indicated that Ab istotypes specifically IgG3 to P. falciparum schizont antigen had been raised in hepatosplenic sufferers compared to handles [10]. Small-area deviation Vorinostat in contact with malaria infections approximated from mosquito densities have already been associated with deviation in the prevalence of splenomegaly in kids up.