Burden and risk factors for Schistosoma mansoni infection among primary school children: A quantitative school-based cross-sectional survey in Busega district, Northern Tanzania

PLOS ONE RESEARCH ARTICLE Burden and risk factors for Schistosoma mansoni infection among primary school children: A quantitative school-based crosssectional survey in Busega district, Northern Tanzania a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 George Ogweno1,2, Vivian Mushi ID1,3*, Valeria Silvestri ID1, Witness Bonaventura1, Nyanda C. Justine ID1, Mololo Noah ID4, Furahini Yoram5, Hussein Mohamed6, Donath Tarimo1 1 Department of Parasitology and Medical Entomology, School of Public Health and Social Sciences, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania, 2 National Institute for Medical Research, Mwanza, Tanzania, 3 Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar es Salaam, Dar es Salaam, Tanzania, 4 Maweni Regional Referral Hospital, Kigoma, Ministry of Health and Social Welfare, Dodoma, Tanzania, 5 Department of Clinical Oncology, School of Medicine, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania, 6 Department of Environmental and Occupational Health, School of Public Health and Social Sciences, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania OPEN ACCESS Citation: Ogweno G, Mushi V, Silvestri V, Bonaventura W, Justine NC, Noah M, et al. (2023) Burden and risk factors for Schistosoma mansoni infection among primary school children: A quantitative school-based cross-sectional survey in Busega district, Northern Tanzania. PLoS ONE 18(1): e0280180. https://doi.org/10.1371/journal. pone.0280180 Editor: Matty Knight, University of the District of Columbia, George Washington University School of Medicine and Health Sciences, UNITED STATES Received: August 31, 2022 Accepted: December 22, 2022 Published: January 12, 2023 Copyright: © 2023 Ogweno et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: The authors received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist. * Abstract Background Intestinal schistosomiasis is one of the most common neglected tropical diseases in Tanzania. Despite massive praziquantel administration, data from Northern Tanzania have reported a prevalence of up to 93.2%. Because the disease is focal, depending on host, environmental and intermediate host factors, there is a need to acquire data in specific settings to better tailor interventions. Therefore, the study assessed the prevalence and factors associated with persistent transmission of intestinal schistosomiasis among school-age children in Busega district, Northern Tanzania. Methods A school-based cross-sectional study was conducted among 363 primary school children, randomly selected from school clusters in the Busega district. A single stool sample was collected from each child for S. mansoni ova and infection intensity examination using KatoKatz. Factors related to intestinal schistosomiasis transmission were acquired through a questionnaire. A malacological survey was carried out to determine the Biomphalaria infectivity rate. Descriptive statistics and logistic regression analysis were conducted to analyse the association between schistosoma infection and factors related to transmission in this setting. PLOS ONE | https://doi.org/10.1371/journal.pone.0280180 January 12, 2023 1 / 18 PLOS ONE Burden and risk factors for Schistosoma mansoni infection among primary school children in Tanzania Results The prevalence of S. mansoni infection was 41.3% (95% CI: 36.3–46.5), statistically significantly higher among the younger group aged less than 11 years (46.4% vs 35.3%, p = 0.032). The intensity of infection was heavy in 1.6% of participants, moderate in 9.6%, and light in 30.9%. Studying at Mwamayombo Primary School (AOR = 2.50, 95% CI: 1.12–5.60) was the only factor significantly associated with S. mansoni infestations. The snail intermediate host belonged to Biomphalaria sudanica species, whose infectivity rate was quantified as 0.97%, thus confirming ongoing transmission in the area. Conclusions There was a high prevalence of S. mansoni infection among school-age children in the Busega district. The presence of the infected Biomphalaria sudanica in the area documents the persistent transmission of the disease, favored by low knowledge and negative attitudes among school-aged children. Hence, the need for multi-approach intervention for schistosomiasis prevention and elimination. Introduction Schistosoma mansoni (S. mansoni) is a trematode parasite acquired by contacting water bodies infested with its intermediate snail host of Biomphalaria spps shedding cercariae [1]. S. mansoni is the agent of hepato-splenic and intestinal schistosomiasis and a species of public health importance in the sub-Saharan setting. The prevalence of schistosomiasis and intensity of infection varies between geographical areas, age groups, and sex [2]. With the effort of intensive control and scaling up of programs by public and private partners, intestinal schistosomiasis remains a serious public health problem [3]. A key epidemiological feature of schistosomiasis is a focal distribution of the disease, with a highly variable prevalence and intensity of infection due to the different interactions of humans, intermediate host snails, and water presence in different settings [2]. Lack of access to water and sanitation and activities involving contact with infected water sources (domestic, recreational, or professional), put children, adolescents, and adults at risk of schistosome infection when exposed to contaminated water bodies [2]. Notwithstanding massive drug administration (MDA) programs put in place to prevent the disease, the prevalence of S. mansoni among school children is still high, and can reach up to 89.9% in some settings in African countries. However, it’s also true that MDA had a significant impact in reducing infection overall in Africa [4]. Due to environmental changes, S. mansoni has also been reported in a geographic area with no previous prevalence of human schistosomiasis [5–9]. The lack of knowledge related to schistosome agents, modality of infection, and preventive actions has been emphasized previously as a factor likely to influence the efficiency of preventive programs [10]. Negative attitudes have also been observed in addition to the lack of knowledge in sub-Saharan settings [11]. Heavy infections in children reduce physical and cognitive development, and when the infection is persistently not treated, it can lead to severe morbidity as well as mortality in serious cases [12]: anaemia, growth stunting, liver failure, portal hypertension, dec (...truncated)