Prevalence, behavioural and social factors associated with Schistosoma intercalatum and geohelminth infections in São Tomé and Principe

A pilot study was conducted in schoolchildren from three main districts of São Tomé to assess the relationship between the prevalence of infections caused by Schistosoma intercalatum or intestinal helminths and individual behaviour and social conditions. Coprological examination revealed an increase of schistosome infections and a persisting high endemicity for ascariasis and trichuriasis. Infection rates were 36.2% for S. intercalatum and 70.8%, 68.5% and 4.6% for Ascaris lumbricoides, Trichuris trichiura and Ancylostomidae, respectively. Out of the 47 children positive for S. intercalatum, 35 (74.5%) were coinfected with one or more geohelminths. Logistic regression analysis of data collected through questionnaire demonstrate that behaviour and/or social conditions in the house were positively associated with S. intercalatum or T. trichiura. Neither sex nor age groups were associated with infections, suggesting that low personal hygiene and sanitation practices were similar for all groups of children. These data are in accordance to those of other studies and highlight the importance of assessing multivariate factors that may contribute to the transmission of these diseases, in order to design integrated control approaches for schistosomiasis and geohelminthiasis which could have more rapid effects on reduction of infections as well as greater cost-effectiveness.