Climate Change and the Prevalence of Trypanosomiasis: A Scoping Review of the Literature

Abstract

Abstract Background: Trypanosomiasis, commonly referred to as sleeping sickness, is a disease transmitted by vectors that are anticipated to be affected by climate change. Numerous studies have indicated that the distribution of tsetse flies is primarily influenced by ecological factors, with temperature and precipitation being key determinants. This study aimed to investigate the relationship between climate change and trypanosomiasis prevalence through a literature review. Methods: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eighty-seven studies met our inclusion criteria. This review examined all relevant studies published in English, with no lower date limits, to provide a comprehensive historical analysis. The final search was conducted in August 2024. The focus was on original quantitative and qualitative research, as well as reports obtained from the Dimensions, Cochrane, EBSCO, Scopus, Web of Science, PubMed, and ScienceDirect databases. Results: Different conclusions were drawn regarding the effects of climate change on the prevalence of human and animal trypanosomiasis. Most studies have shown that trypanosomiasis has declined due to temperature extremes, which hinder vector breeding, reduce infection risk, cause habitat fragmentation resulting from human activity, and drought-causing contraction of the vector’s range. Several bioclimatic models have suggested a decrease in the number of vectors (tsetse flies). However, the optimal temperature range between 20 ◦C and 30 ◦C facilitates an increase in trypanosomiasis cases. Heavy precipitation is associated with flooding, which causes pupae to drown, directly affecting the survival of the vector tsetse fly. Conclusions: Trypanosomiasis is likely to persist in the environment owing to the creation of new suitable habitats and stochastic environments, resulting in the invasion of more virulent parasite strains, increased blood meal sources, and higher infection rates.