Influence of climatic variables on the number of cases of visceral leishmaniasis in an endemic urban area

Abstract

Background Visceral leishmaniasis (VL) is a neglected tropical disease endemic in several countries, with as much as 97% of cases in the Americas attributable to Brazil. Despite considerable investment in disease control, Belo Horizonte is one of the Brazilian municipalities with the highest mortality rates. The present study aimed to investigate the association between climatic variables and the increase in the number of VL cases in Belo Horizonte. Methods The study analyzed 1,897 laboratory-confirmed cases of VL registered by the municipality’s Epidemiological Surveillance from 1994 to 2019. The climatic variables were obtained from the National Institute of Meteorology. Results The first reported VL case was detected in 1994, and since then, the disease has spread throughout the municipality. The disease was most common in the very young age groups, 1 to 4 years, and older groups, 40 to 49 years old. Approximately 63% of detected cases were men. A peak number of cases were observed in 2004, 2006, 2008 and 2017. Total precipitation was significantly associated with the number of VL cases, with more cases depending on rainfall (P=0.006), thus confirming that climate contributes to the disease spread. Conclusions These results demonstrate the need for the actions of the Visceral Leishmaniasis Surveillance and Control Program to be reinforced in years with above-average rainfall, a situation that is increasingly more frequent in Southeastern Brazil due to global climate change.