Interaction between the chytrid Batrachochytrium dendrobatidis and the Ranavirus in anuran assemblages from the Southern Atlantic forest

Abstract

Among the many threats to the global biodiversity, emerging infectious diseases are considered the main causes. Ranavirus (Rv) and Batrachochytrium dendrobatidis (Bd) are responsible for most declines of amphibian populations, which is the most threatened vertebrate taxa. Both Bd and Rv are spread via water and via direct contact with a sick individual, making dispersion extremely effective. The American bullfrog (Lithobates catesbeianus) is usually tolerant to both Bd and Rv, and is thought to be a carrier for these pathogenic agents. The bullfrog trade for food leads to a global movement of Bd and Rv, which can contribute to the introduction of such pathogenic agents into new regions and sensitive populations. In Brazil, well-established bullfrog populations can be found in the Atlantic Forest, where the distribution of Bd is widespread. However, the knowledge on Rv is limited to bullfrog farms, and the interaction between the two pathogens was never explored in Brazil. Therefore, we will investigate the presence of Rv in areas where bullfrogs are abundant. As coinfection of these two pathogens has been reported for amphibian species in other regions of the world, and it can intensify amphibian populational declines, we will also sample anuran specimens in order to detect the presence of both microorganisms. By doing that, we will be able to identify the virus dynamics in different species and habitats, and the interaction between Bd and Rv in anuran species from this biome. Consequences of coinfection will be discussed in order to help on amphibian conservation action plans. (AU)