Effects of the infection by the Batrachochytrium dendrobatidis on the cardiac morphophysiology of bullfrog tadpoles

Abstract

Several studies have been indicating an alarming decline of amphibian populations worldwide. The chytridiomycosis, an emergent infection caused by the fungus chitridio Batrachochytrium dendrobatidis (Bd) that infects anuran skin, have been considered one of the main factors underlying this decline over recent decades. Predominantly aquatic, Bd spreads rapidly in the environment, having the ability of infecting most amphibian species. Despite de action mechanisms by which Bd causes this infection are not yet completely elucidated, it is know that amphibian skin is singular among vertebrates due to its role played in the homeostatic balance. As a consequence, Bd infection can affect water and ionic balance, therefore reducing the transportation of electrolytes that are essential to the cardiac dynamics and then compromising the cardiac performance of infected animals. Indeed, it was already demonstrated that infected animals can die by asystole. This observation gives clear evidence of the negative impact of Bd infection over amphibian cardiac function. In this sense, the aim of this project is to evaluate the impact of the infection by the fungus that causes chytridiomycosis (Bd) over the cardiac morphophysiology of bullfrog tadpoles by the analysis of its effect on animals' level of activity, cardiac frequency, relative ventricular mass, and the cardiac morphology.