Microscopic Fungus Causes Skin Infection, Population Decline in Frogs

A microscopic fungus that results in skin infections and lesions in amphibians is to blame for a population decline in frogs.

Microscopic Fungus and Skin Infections

The microscopic fungus that causes chytridiomycosis is fatal to many species of amphibians, according to Vance T. Vredenburg, San Francisco State University Department of Biology professor and associate chair, and also an expert on the disease.

Chytridiomycosis, a condition brought on by this fungus, is the worst case of a vertebrate illness ever documented. More than 500 species have been impacted, and many of these species experienced mass extinctions shortly after fungal invasions and skin infections.

By infecting their skin, chytridiomycosis kills frogs by causing skin shedding and several other symptoms, such as ulcers. Frogs and other amphibians carry out vital ion transfer across their skin layers and take in oxygen through their skin.

Vredenburg co-authored the study, which was recently published in the journal Frontiers in Conservation Science.

Chytridiomycosis

According to a 2019 study published in the journal Science, fungal infection is to blame for the global population decline of 39% of amphibian species.

It was initially discovered in Queensland, Australia, in the 1990s after several frog species were discovered dead. Although it exists everywhere, Central and South America, Australia, and North America are where it is most common. The fungus is believed to spread through spores released into water from amphibian skin.

According to Vredenburg, the fungus was discovered for the first time in Australia in 1993 and was described or given a scientific name six years later.

The scientific team has used amphibian collections from natural history museums to track the fungus's global spread. Vredenburg stated that even though there have been hundreds of scientific papers on this pathogen and that there are believed to be more than 1,200 species of amphibians found in Africa, very few of these studies have been carried out there.

Scientists are still baffled as to why it took the fungus so long to fully invade Africa's wildlife.

Frog Population

Unfortunately, little can be done to stop the slow spread of this infection among the world's amphibians since there is neither a cure nor a vaccine available, but some frogs are showing signs of recovery.

According to Vredenburg, some amphibians are being found in areas where species were previously believed to have vanished due to fungus epidemics. One species of mountain yellow-legged frog, the Sierra Nevada yellow-legged frog, has recovered in California, where two other species were wiped out by the fungus. This frog's population in Yosemite National Park has increased despite the fact that it was severely infected in the 1980s.

Although increased cloud cover brought on by climate change may result in cooler daytime temperatures and warmer nighttime temperatures, which would be more conducive to the growth of the microscopic fungus, previous studies have found that climate change may actually be beneficial to the fungus. For example, because the fungus thrives in temperatures ranging from 63 to 77 degrees Fahrenheit, any deviation could impact the fungus.

Climate change could lead to more hot, arid, and dry conditions, which could harm the fungus because it cannot grow above 86 degrees Fahrenheit and needs moist environments to propagate its spores, Newsweek reports.