Residence Time, Water Contact, and Age-driven Schistosoma mansoni Infection in Hotspot Communities in Uganda

Abstract

Schistosomiasis is the second most important parasitic infection after malaria in terms of its socioeconomic impact and is endemic in 78 countries. It affects more than 240 million people worldwide, with 90% of cases occurring in sub-Saharan Africa. In Uganda, Schistosoma mansoni is the most common species, with more than seven million people infected and 17 million living at risk despite mass drug administration (MDA) of praziquantel initiated more than 16 years ago. There has been a shift in the WHO schistosomiasis goals from controlling morbidity to elimination as a public health problem. Understanding the drivers of infection in persistent transmission hotspots despite ongoing control interventions is paramount. We conducted a cross-sectional epidemiological study of 381 individuals in Bugoto community, Mayuge district, Eastern Uganda, along with a structured survey to ascertain drivers of S. mansoni infection. Bugoto has had community-wide MDA since 2003. We detected an S. mansoni prevalence of 52% across the whole community and a prevalence of 71% in school-age children. This qualifies Bugoto as a highly endemic community according to WHO guidelines. Using a multivariate logistic regression, we found that S. mansoni infection was best explained by age group, longer residence times, and at least 5 minutes of daily contact with lake water. Schistosoma mansoni infection remains a large burden across this community. This study identifies opportunities for interventions that reduce lake water contact, expand treatment eligibility to all at risk, and improve MDA coverage for long-term residents in these settings to control schistosomiasis in persistent transmission hotspots.

Understanding perceptions of schistosomiasis and its control among highly endemic lakeshore communities in Mayuge, Uganda

“…However, high intensities are also strongly associated with high levels of water contact activities [ 29 , 61 , 62 ]. Corroborating quantitative research in Bugoto [ 50 ] that showed people contacting lake water daily and for long hours, we observed people engaging daily with high-risk water contact activities, regardless of age and gender, reinforcing the notion that schistosomiasis is hard to prevent. We observed and heard that people continue with their daily activities at, and in, the lake whether they are aware of the risk or not, because it is the major source of livelihood and free water.…”

“…mansoni : Bugoto, Bwondha, and Musubi, all on the shores of Lake Victoria in Mayuge District, Eastern Uganda ( Fig 1 ). In these communities prevalence and intensities are high, for example 71% of people are infected in Bugoto community, [ 50 ] with likely similar infection levels in Musubi and Bwondha [ 27 , 37 ]. Infection risk behaviour is also high [ 50 ], whilst MDA coverage remains low [ 15 , 50 ] despite over 15 years of annual MDA indicating that additional, locally informed, improved interventions are needed.…”

Associations of water contact frequency, duration, and activities with schistosome infection risk: A systematic review and meta-analysis

“…It is plausible that relatively low levels of water contact are sufficient for becoming infected. A study by Moses et al [ 63 ] in Uganda noted that water contact duration of as little as five minutes per day was significantly associated with S . mansoni infection risk.…”

“…It is plausible that relatively low levels of water contact are sufficient for becoming infected. A study by Moses et al [63] in Uganda noted that water contact duration of as little as five minutes per day was significantly associated with S. mansoni infection risk. Therefore, water contact intensity may be less relevant for predicting individual-level infection status than knowledge on whether someone had any water contact [46].…”

A feasibility test of a large-scale implementation of schistosomiasis elimination under China-Zimbabwe cooperation: a pilot study protocol

“…The disease compromises public health by contributing to malnutrition in children, preventing them from attending school, impairing cognitive development, and increasing high risk of getting HIV especially in women [2,7,15,16]. Although given present effective interventions, SCH remains the second to malaria in terms of its public health signi cance [8, 17,18]. Professional and domestic activities such as farming, bathing, washing, and playing expose local dwellers to infection [19][20][21][22].…”