Modeling of Human Rabies Cases in Brazil in Different Future Global Warming Scenarios

Abstract

Bat species have been observed to have the potential to expand their distribution in response to climate change, thereby influencing shifts in the spatial distribution and population dynamics of human rabies cases. In this study, we applied an ensemble niche modeling approach to project climatic suitability under different future global warming scenarios for human rabies cases in Brazil, and assessed the impact on the probability of emergence of new cases. We obtained notification records of human rabies cases in all Brazilian cities from January 2001 to August 2023, as reported by the State and Municipal Health Departments. The current and future climate data were sourced from a digital repository on the WorldClim website. The future bioclimatic variables provided were downscaled climate projections from CMIP6 (a global model ensemble) and extracted from the regionalized climate model HadGEM3-GC31-LL for three future socioeconomic scenarios over four periods (2021-2100). Seven statistical algorithms (MAXENT, MARS, RF, FDA, CTA, GAM, and GLM) were selected for modeling human rabies. Temperature seasonality was the bioclimatic variable with the highest relative contribution to both current and future consensus models. Future scenario modeling for human rabies indicated a trend of changes in the areas of occurrence, maintaining the current pace of global warming, population growth, socioeconomic instability, and the loss of natural areas. In Brazil, there are areas with a higher likelihood of climatic factors contributing to the emergence of cases. When assessing future scenarios, a change in the local climatic suitability is observed that may lead to a reduction or increase in cases, depending on the region.

Keywords: Brazil; CMIP6; climate change; distribution modeling; human rabies.

Figure 1

South American political map showing Brazil with international borders, neighboring countries, states, and regions.

Figure 2

Modeled climatic suitability for human rabies cases in Brazil. Modeled climatic suitability (consensus model) for all seven algorithms under current climate conditions is presented. The data were provided by WorldClim [42]. For visualization, the maps were built using QGIS version 3.16 “https://qgis.org/pt_BR/site/ (accessed on 4 October 2022)”.

Figure 3

Future climate suitability for human rabies in Brazil. Modeled climate suitability (consensus model) for all seven algorithms under future climate conditions using three updated scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5) during four CMIP6 periods in the period 2021–2100. The data were provided by WorldClim [42]. For visualization, the maps were built using QGIS version 3.16 “https://qgis.org/pt_BR/site/ (accessed on 4 October 2022)”.

Figure 4

Percentage change in the predicted future climate suitability for human rabies in Brazil. The modeled climate suitability (consensus model) for all seven algorithms under future climate conditions using three updated scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5) over four periods (2021–2100) from CMIP6 have been depicted. The data were provided by WorldClim [42]. For visualization, the maps were built using QGIS version 3.16 “https://qgis.org/pt_BR/site/ (accessed on 4 October 2022)”.