CLIMATE CHANGE AND CHAGAS DISEASE IN THE AMERICAS: A QUALITATIVE SYSTEMATIC REVIEW

While many studies have found associations between climate change and factors affecting Chagas disease transmission, the future impact of climate change on the global spread of Chagas disease remains debatable. A qualitative, systematic review was conducted to assess the impact of climate change on Chagas disease transmission in the Americas (Central America, South America, and North America). The literature search was performed in January 2019 using the keywords climate, Chagas, and “trypanosoma cruzi” and the electronic databases PubMed, Scopus, and Ovid. Searches retrieved records from 1982 through 2019. The initial electronic database search identified a total of 191 record documents and 23 additional records through other sources. After assessment for inclusion eligibility, seven articles fulfilled the selection criteria and were included in the review. Most studies under review showed that Chagas disease transmission is highly sensitive to climate factors, specifically temperature, relative humidity, and precipitation. The majority of reviewed studies conducted in Latin American predict stable or decreased vector distributions and T. cruzi transmission rates as future consequences of climate change in their study areas. Notably, Mexico was the only geographical area studied in the Americas where Chagas disease is currently endemic and also predicted to be at increased transmission risk under future climate change scenarios. Similarly, an expansion of areas in the United States at increased risk for Chagas disease transmission is also expected over the next several decades under climate change scenarios. Of particular interest is the predicted northern shift of triatomine species to central regions of the United States with historically unsuitable climates for T. cruzi vectors. The weight of evidence regarding the influences climate change may pose on T. cruzi vector species distributions demonstrates the sensitivity of Chagas disease transmission to future climate variability. In order to advance forecasts for the impact climate change may have on Chagas disease transmission in the Americas, it is imperative to further develop, utilize, and perhaps combine predictive species distribution modeling approaches that integrate accurate, long term data on climate variables, vector species distributions, Chagas disease incidence, as well as other socio-ecological variables