A link between individual body temperature and risk of infection with an amphibian chytrid fungus in three frog species is explored in a paper published in Scientific Reports this week.
Chytridiomycosis, a disease caused by the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), is responsible for declines and extinctions in many amphibian populations. Previous research has revealed a link between environmental temperature and disease prevalence at the population level in frogs. Jodi Rowley and Ross Alford studied three species of Australian rainforest frog, tracking individual body temperatures. They show that a frog’s probability of infection declines as it spends more time above 25oC, the highest temperature at which Bd grows optimally.
It remains unclear whether the relationship between Bd infection and higher body temperatures is causal. Natural or artificial selection for higher thermal preferences could reduce susceptibility to this pathogen, the authors suggest, but individual frogs may also alter their body temperatures for other reasons, such as to aid digestion or growth. The results could also reflect a tendency for infected frogs to maintain an altered body temperature. Further research is needed to understand more fully the relationship between body temperature and infection risk.