Impact of praziquantel mass drug administration campaign on prevalence and intensity of Schistosoma haemamtobium among schoolchildren in Bahi district, Tanzania

Abstract

As part of the Tanzania National Schistosomiasis Control Programme, Bahi district in central Tanzania, received two annual rounds of praziquantel mass drug administration (MDA) to control urinary schistosomiasis in schoolchildren. The objectives of this study were to assess the impact of the two rounds of MDA on prevalence and intensity of Schistosoma haemamtobium and the impact of MDA campaigns on knowledge of urinary schistosomiasis, safe water use and contact with potentially unsafe water bodies. A quantitative cross-sectional study was carried out among schoolchildren in March and April, 2013. A structured questionnaire was used to collect information on MDA uptake, knowledge of schistosomiasis, sources of water for domestic and other uses. Urine samples were collected from each pupil to examine prevalence and intensity of S. haematobium. Transmission of schistosomiasis was assessed by sampling Bulinus spp snails for cercarial shedding. Uptake of MDA was 39.5% in 2011 and 43.6% in 2012. Prevalence of S. haematobium significantly dropped by 50.0% from 26% in 2011 to 15% in 2012 (p = 0.000). Prevalence of S. haematobium was significantly low in MDA participating (3.1%) than non-participating (28.5%) schoolchildren (p = 0.000). MDA campaigns had significant impact on knowledge of the disease (p = 0.02) and borderline impact on safe water use (p = 0.04) but had no impact on avoidance of contact with unsafe water bodies (p = 0.06). Bulinus spp. snails were found shedding schistosome cercariae indicating environmental contamination with viable S. haematobium eggs. In conclusion, though MDA significantly reduced prevalence of S. haematobium, uptake was below 50.0% and below the World Health Assembly resolution 54.19 target of 75.0% for 2010. Non-participation in MDA was the likely source of S. haematobium eggs in the environment hence the observed 15.0% prevalence of S. haematobium infection; and cercarial shedding Bulinus spp. snails indicating continuity of transmission hence the need for further health promotion campaigns.