Biologists from the University of California have discovered that more than 40% of amphibians are currently threatened with extinction due to the contagious, fungal disease chytridiomycosis. there was work published Frontiers in Conservation Science.
The pathogen Batrachochytrium dendrobatidis (Bd) fungus that causes kitridiomycosis is highly contagious and affects salamanders, salamanders, horse flies and especially frogs and toads. The disease rarely kills tadpoles and often adults. In them, the fungus causes exfoliation of the skin, lethargy, weight loss and eventually cardiac arrest.
In their study, the scientists consulted the scientific literature from 1852 to 2017 to search for records of the presence or absence of apparent chytrid infection in amphibians in Africa. They also performed PCR testing for Bd on nearly 3,000 museum amphibian samples. Between 1908 and 2013 they met in Cameroon, Ethiopia, Kenya, Lesotho, Tanzania and Uganda. The researchers also took skin samples from 1,651 live amphibians caught in Burundi, Equatorial Guinea, Cameroon and the Democratic Republic of Congo between 2011 and 2013.
The results show that the oldest Bd-positive amphibian originated in Cameroon in 1933. Until 2000, the prevalence of the fungus was below 5%, but then there was a sharp jump to 17% and to 21% in the 2010s. In some countries the prevalence has increased to 74%.
The team says that since 2000 there has been a largely ignored but marked increase in the prevalence of Bd, which poses a threat to amphibians in Africa. The regions most at risk are eastern, central and western Africa.
“We have a hypothesis that the stress caused by climate change may make amphibians more susceptible to pathogens. It is not possible to eliminate this microscopic pathogen in the wild, but we can try to mitigate its impact on nature,” the researchers said.