Epidemiological burden of schistosomiasis among schoolchildren in conflict-stricken mesoendemic districts of Yemen: A decade after national mapping

TL;DR

Schistosomiasis remains a public health issue in Yemen despite mass drug campaigns, with increased infection rates in schoolchildren over the past decade.

Contribution

This study provides updated epidemiological data on schistosomiasis in Yemen's conflict-affected mesoendemic regions, highlighting the need for integrated control strategies.

Findings

21% of schoolchildren were infected with schistosomiasis, with S. haematobium being more prevalent than S. mansoni.

Infection rates increased in all study districts compared to 2014, despite mass drug administration.

Key risk factors included male gender, age ≥10 years, large household size, and contact with open water sources.

Abstract

Despite multiple rounds of mass drug administration (MDA), schistosomiasis remains a major public health problem in Yemen. This study assessed the burden of schistosomiasis among schoolchildren in mesoendemic districts over a decade after the 2014 national mapping in the context of the ongoing humanitarian crisis, conflict, and disrupted control efforts.

A cross-sectional study was conducted among 348 schoolchildren aged 5–15 years in three randomly selected mesoendemic districts: Al Husha, Bura, and Habur Zulaymah districts. Data on sociodemographics and potential risk factors were collected using a pilot-tested, structured questionnaire. Parasitological examinations for Schistosoma haematobium and S. mansoni were performed using urine filtration and Kato-Katz techniques, respectively. Independent predictors of infection were identified using multivariable binary logistic regression.

The overall schistosomiasis prevalence among schoolchildren was 21% (95% CI: 17, 25), with 13.5% infected with S. haematobium, 6% with S. mansoni, and 1.4% co-infected. Compared to 2014, prevalence increased across all study districts, particularly for S. haematobium. Most infections were of light intensity. Infection with S. haematobium was significantly associated with dysuria, macrohematuria, microhematuria, and proteinuria. Independent predictors of schistosomiasis included male gender (AOR = 2.6; 95% CI: 1.34, 4.82; P = 0.003), age ≥ 10 years (AOR = 2.4; 95% CI: 1.20, 4.92; P = 0.013), household size larger than eight members (AOR = 2.4; 95% CI: 1.28, 4.63; P = 0.007), and contact with open water sources (AOR = 2.5; 95% CI: 1.20, 5.19; P = 0.014).

Despite multiple MDA campaigns, schistosomiasis remains moderately endemic in the districts of Yemen classified as mesoendemic in 2014, with an increased S. haematobium prevalence. While MDA has reduced the prevalence of heavy infections, transmission persists. These findings underscore the need for an integrated strategy combining biannual MDA, health education, improved sanitation, and environmental management to interrupt transmission.

Even after repeated mass drug administration campaigns to combat schistosomiasis in Yemen, the disease is still a public health challenge. We conducted a survey among 348 schoolchildren in three randomly selected districts of the country to assess the prevalence, intensity, and risk factors associated with schistosomiasis over a decade since the national mapping in 2014 to see whether the situation has improved. We found that 21% of children were infected, with urogenital disease being more common than intestinal disease. However, most infections were mild. Notably, the disease prevalence increased in all districts compared to 2014, indicating persistent transmission. Our findings suggest that better access to safe water, proper sanitation and health education, along with regular treatment, are needed to stop the transmission of schistosomiasis in Yemen.

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