The deadliest fungus to ever infect wildlife is back and spreading, ravaging countless amphibian populations as it moves across Africa.
The microscopic fungus, named Batrachochytrium dendrobatidis, affects the keratin in the skin of amphibians. Infection with the fungus causes a fatal disease known as chytridiomycosis, which has a gruesome effect on frogs, toads, and other amphibians.
The skin of an infected frog will slough off as the animal experiences extreme lethargy, weight loss, and eventually, heart failure. The disease is not only devastating but highly contagious, spreading from amphibian to amphibian via spores released by the deadly fungus.
“To see a frog die of chytrid is probably the worst experience I’ve ever had,” Anthony Waddle, a conservation biologist, told Yale Environment. “You’re watching the soul of nature leave it.”
The infection doesn’t affect species equally, experts say. While some amphibian populations are decimated by the fungus, others seem to largely withstand it. The populations it does affect, however, suffer irreversible damage.
Like other pathogens, its success depends on a variety of factors. These include the susceptibility of the host, the lethality to the host, and the suitability of the host’s environment. The deadly fungus can even affect individuals within the same species differently.
“The risks are significant,” Vance Vredenburg, a professor in the Department of Biology at San Francisco State University, told Newsweek. “In fact, this disease is the worst in recorded history. It has infected over 1,000 species of amphibians and has caused declines in approximately 500 species—dozens have gone extinct.”
Lack of Research Allowed Deadly Fungus to Spread Unchecked, Scientists Say
Scientists detected the presence of the deadly fungus way back in the 1800s. Since the 1980s, however, it’s truly taken root, both in Africa and worldwide. Over the past 40 years, the pathogen has spread, causing mass deaths among amphibious populations around the world.
As scientists explained in a recent study published in Frontiers in Conservation Science, the fungal plague remains prevalent to this day. In the past two decades or so, the deadly fungus has spread rapidly across Africa, an area scientists believed escaped the disease.
Unfortunately, the disease long went overlooked. As a result, mass population declines and even extinctions might have already occurred without widespread notice. Africa houses around 16% of the world’s amphibian species. Despite this, there are no records of a Bd epizootic (the wildlife equivalent of an epidemic).
Researchers now believe this lack of record is likely due to a lack of sampling in the continent rather than a lack of the deadly fungus.
“We should be concerned,” Vredenburg said. “This is the first fungal pathogen to cause this level of mortality in vertebrates. While this is not a The Last of Us moment for humanity, we should try to learn from this to better understand what factors have led to a fungal pathogen having such a profound effect on hosts.”