Impacts of climate change upon the incidence of zoonotic diseases in Brazil

Climate change has become a significant factor in the emergence of diseases and must therefore be prioritized when addressing these issues. Changes in air temperature, relative air humidity, and precipitation may be associated with the emergence of zoonoses. The purpose of this study is to evaluate the relationship between climatic parameters and the prevalence of zoonoses in São Paulo State, located in the southeastern region of Brazil. Four zoonotic diseases with distinct modes of transmission and high incidences were selected for the study: leptospirosis, visceral leishmaniasis, spotted fever, and hantavirus infection. The study examined historical data on human cases of these diseases from 2001 to 2020. Regression analysis was used to determine the relationship between climatic and environmental variables, such as air temperature, relative air humidity, precipitation, latitude, elevation, predominant biome, deforestation, and the incidence of the selected zoonoses per year and per 100,000 inhabitants. Climatic and environmental parameters were associated with the incidence of selected zoonoses, primarily favoring an increase in vector-borne zoonoses (visceral leishmaniasis and spotted fever). However, despite the association between hantavirus infection and climatic factors, climate change will probably have little to no influence on its incidence in São Paulo State. Finally, climate change may be associated with a decrease in leptospirosis incidence. Climate change favors vector-borne diseases, requiring transdisciplinary attention and greater involvement from health authorities to allocate resources for strategic disease surveillance, control, and prevention.