A review of environmental determinants of schistosomiasis prevalence in Africa

Background: In Africa, different studies have been conducted on schistosomiasis, one of the most devastating parasitic diseases in tropical countries. However, environmental determinants have not fully been explored as important means of additional strategies for prevention and control of the disease. Therefore, the aim of this study was to review environmental determinants that are associated with schistosomiasis prevalence in Africa.
Methods: A systematic review was conducted by searching Pubmed, Embase and Google scholar for articles published between 2000 and April 2014. A total of 492 articles were retrieved. The inclusion and exclusion criteria was directed by the suitability of the title, the year and the continent the study was conducted, duplication and related outcome. Twenty four cross sectional studies met the inclusion criteria. Evaluation of each article’s findings was conducted based on the study design, selection of participants, measurement of exposures and outcomes. A data capturing spreadsheet was created in Excel and used for data abstraction. Study details were then transferred to Review Manager 5 Meta analytical package for further processing.
Results: The results obtained indicated that of the 6634 infected participants in twenty four studies conducted in ten countries, males were at 59% and females were at 41% showing that males were more likely to be infected by schistosomiasis than females. Schistosomiasis prevalence was also found to be more among participants living closer to rivers/streams and ponds emphasizing the fact that water bodies were the leading environmental determinant to schistosomiasis prevalence. Although Anto et al. (2013) and Sammy (2013) found strong associations between schistosomiasis prevalence and wet farming and fishing, when read together with other studies, this environmental determinant was insignificant showing that it has a low contribution to the prevalence. Unsafe water and sanitation alone had no direct association with schistosomiasis prevalence.
Conclusion and Recommendations: Findings of this study suggest that living close to water bodies is associated with schistosomiasis prevalence while wet farming and fishing has a low part to play. This study suggests that use of rivers and streams increases exposure to schistosomisis. Urgent interventions that focus on behavior and attitude change and provision of safe water as well as good sanitation to reduce usage of rivers/streams are therefore needed.