Factors influencing persistence of urogenital schistosomiasi sAmong school children in Chake-chake District, Zanzibar – Tanzania

Abstract

Background: Despite the implementation of eight rounds of mass drug administration (MDA) with praziquantel to all school-aged children and snail control measures since 2012, there are still hotspot areas with urogenital schistosomiasis prevalence of greater than 10% in Chake- Chake District, Zanzibar. Factors influencing the persistence of urogenital schistosomiasis transmission in these hotspots are not well characterized. Therefore, this study was designed to delineate specific factors influencing the persistence of urogenital schistosomiasis among school children in Chake-Chake District. Materials and Methods: A cross-sectional study was conducted among school children at Ole, Vitongoji and Ngomeni schools in Chake-Chake District from August 2020. The schools were chosen using a probability proportional to size method. At each school, standard II to VI pupils were selected using simple random sampling. A single urine sample was obtained from all pupils and examined for S.haematobium eggs using sedimentation technique. Urine samples confirmed positive were later examined by filtration technique for quantification of eggs and establishment of infection intensity. Structured interview schedule and checklist were used for data collection on factors influencing the persistence of urogenital schistosomiasis infections such as water contact activities, sanitation facilities, knowledge and attitude. In addition, morphologically identified Bulinus sp. snails were examined for infection using the cercaria shedding method. Data were summarized by descriptive statistics, while proportions were compared by Pearson‟s chi-square and Fisher‟s Exact test. Logistic regression analyses were used to test the association between dependent and independent variables using odd ratios and 95% CI, the significance level was set at a p- value of p <0.05. Results: Ngomeni and Vitongoji primary schools had more children with S. haematobium infection. Majority of pupils had average level of knowledge, good attitude about urogenital schistosomiasis, high MDA uptake and availability and good use of sanitation facilities among school children. When bivariate and multivariate logistic regression analysis were performed, swimming was associated with increased likelihood of acquiring S. haematobium AOR= 22.204, 95% CI: 7.487-65.074, p =0.001 and good attitude on urogenital schistosomiasis AOR=0.004, (95% CI: 0.006 - 0.074, p<0.011) were associated with reduced risk of S. haematobium infection. Conclusion: The study confirms that urogenital schistosomiasis is still prevalent among pupils in Chake-Chake district; nevertheless, the overall prevalence was 9.6% slightly lower than that reported in the previous years. Conceivably, persistent S. haematobium transmission is influenced by the prevailing risk factors for transmission (presence of infected pupils, water contact activities such as swimming). Presence of Bulinus snails‟ intermediate hosts in sampled water sources indicates potential/likelihood of transmission of schistosomiasis in the study area.