Prevalence and risk distribution of schistosomiasis among adults in Madagascar: a cross-sectional study

Abstract

Background: Eliminating schistosomiasis, a parasitic disease of poverty, as a public health problem is associated with the 2030 United Nations agenda for Sustainable Development Goals, including Universal Health Coverage (UHC). Current vertical control programs systematically neglect adults and impede reaching UHC. This dissertation aimed to analyze prevalence and distribution of risk factors for schistosomiasis among Malagasy adults to motivate the shift towards control strategies including adults. Methods: This cross-sectional study was conducted between March 2020 and January 2021 at three primary health care centers in Andina, Tsiroanomandidy and Ankazomborona in Madagascar and included 1482 adult participants. Prevalence rate was determined by a semi-quantitative PCR assay from blood probes collected and risk factors for schistosomiasis were analyzed by univariable and multivariable logistic regression using the data from a case report form. Results: Highest prevalence of S. mansoni was found in Andina with 59.5%, highest prevalence of S. haematobium was described in Ankazomborona with 61.3% and most co-infections with both species were also found in Ankazomborona with 3.3%. Protective factors for infection with both species were higher age and not working as a farmer. Higher prevalence of both species was observed among males. Living in a rural area, a low education level and no previous treatment with praziquantel increased the risk of infection with S. mansoni. Conclusions: Our data show that adults in Madagascar are at high-risk for schistosomiasis. The exclusion of adults from control strategies for schistosomiasis in high endemic countries like Madagascar may hamper reaching the goal of elimination and represents a clear barrier for the achievement of UHC. Our findings suggest that re-addressing public health strategies for schistosomiasis towards broader approaches including adults will be needed to reach those goals.