The Effect of Weather Events on Dengue Fever in Brazil 2014-2022

Abstract

Dengue fever is a mosquito-borne infectious disease that is spread through the bite of an infected Aedes aegypti or Aedes albopictus mosquito. Half the world’s population lives in a dengue fever risk zone. There are an estimated 100 million symptomatic dengue fever cases each year with 40,000 deaths reported. Brazil reports the highest annual dengue fever cases in Latin America. In 2022, Brazil recorded 2.36 million dengue fever cases, the highest number of cases ever recorded in the country.

We designed a retrospective ecological study to evaluate the temporal trends and the association between weather events and dengue fever incidence in Brazil from 2014-2022. We also described the demographic trends of dengue fever in Brazil during the study period. We used the PAHO Health Information Platform for the Americas database to obtain dengue fever data and the National Centers for Environmental Information database to obtain meteorological variables. We used the generalized estimating equation to assess the association between weather trends and dengue fever infections in Brazil from 2014-2022.

After evaluating the trends in dengue fever using generalized estimating equation, we did not find an individual association between precipitation and temperature with dengue incidence, but when evaluating these variables together, precipitation emerged as a significant factor associated with dengue fever incidence. We created data derived quintile temperature categories to determine if precipitation was associated with dengue incidence at certain temperature thresholds. There was an association between precipitation and dengue incidence when temperatures were less than ≤76.66℉. We did not find that temperature modified the association between precipitation and dengue fever.