Environmental Drivers of Ranavirus Infection in Anurans of the Brazilian Atlantic Forest

Anthropogenic habitat alteration makes amphibians particularly susceptible to pathogens such as Ranavirus (Rv). Despite severe fragmentation, Brazil's Atlantic Forest remains understudied regarding Rv distribution and impacts. We fill these gaps by mapping Rv across six amphibian communities from areas with varying habitat alteration to identify key conservation areas. We investigated whether susceptibility varies among hosts considering their reproductive modes and habitats. We screened ethanol-preserved livers from specimens previously tested for Batrachochytrium dendrobatidis (Bd) to detect potential co-infections, with emphasis on regions lacking Rv data. Our findings demonstrate that Rv is widespread across sampled anuran communities, with a 27% prevalence, and a few Rv⁺ individuals (n = 8) were found co-infected with Bd. As expected, anurans from sites experiencing severe habitat degradation, particularly the deforested landscapes of Linhares and Santa Teresa, are more prone to infection by Rv, and aquatic species suffer higher odds of Rv infection than terrestrial ones. Contrarily, anurans from less disturbed sites tend to bear higher Rv infection burdens, and infection intensity diminishes as elevation increases. These results highlight the urgent need for targeted habitat restoration, regular pathogen surveillance, and integrated conservation strategies to mitigate disease impact and preserve amphibian diversity in threatened Atlantic Forest ecosystems in Brazil.