Current status of Schistosoma mansoni and the factors associated with infection two years following mass drug administration programme among primary school children in Mwea irrigation scheme: A cross-sectional study

BACKGROUND Schistosomiasis is a major public health problem in Kenya as well as in many other tropical countries and is considered one of the most prevalent diseases in the rural population. Between 2004 and 2009, primary school children in Mwea irrigation scheme were treated for Schistosoma mansoni. In the four year control programme, there was occurrence of light re-infection with S. mansoni. Therefore, the aim of this study was to assess the current prevalence of S. mansoni, infection two years after the withdrawal of mass drug administration (MDA) programme. METHODS We carried out a cross-sectional study on a population of 387 children attending 3 primary schools located in Mwea irrigation scheme. Children, aged 8-16 years were interviewed and screened for S. mansoni using duplicate Kato-Katz thick smears. Comparisons of prevalence by age group and gender were tested for significance on the basis of the Wald test. Best prediction factors for infection with S. mansoni were selected using forward - stepwise variable selection method. RESULTS The overall prevalence of S. mansoni was 53.7 %, (95%CI: 49.0-59.0, p-value = 0.000). Male children had higher prevalence of infection, 66.1 % (95%CI: 59.8-73.2, p-value = 0.000) compared to females. The gender (sex) of a child was the only factor reported to be significantly associated with S. mansoni infection, (OR = 1.9, p-value = 0.015, 95%CI: 1.13-3.21). CONCLUSIONS There was high prevalence of S. mansoni infections in the study area, two years after the withdrawal of MDA programme. We suggest that treatment should be continued in the school children at regular intervals, monitoring and surveillance intensified to ensure interruption of transmission areas.