Deadly, highly contagious fungus spreading in amphibians ‘worst in history’

A highly contagious and deadly fungal disease – considered the worst to affect animals in history – is spreading and putting amphibians at risk across the continent.

A deadly disease known as chytridiomycosis is caused by a microscopic fungus called Batrachochytrium dendrobatidis (Bd). Infection with this fungus has a devastating effect on frogs, toads and other amphibians.

The disease causes these animals to shed their skin and cause other symptoms such as lethargy, weight loss and ultimately heart failure. The disease is highly contagious and is transmitted through the spores released by the fungus.

“The risks are significant,” said Vance Vredenburg, a professor in San Francisco State University’s Department of Biology. Newsweek. “In fact, this disease is the worst in history. It has infected more than 1,000 species of amphibians and caused the decline of about 500 species – dozens have become extinct.”

Stock photo: A dead frog. A highly contagious and deadly fungal disease is spreading in Africa, putting amphibians at risk across the continent. iStock

Since the 1980s, the pathogen has spread and caused mass deaths of amphibians around the world. It continues to spread to this day.

Research published in the journal Frontiers of nature conservation science has now found that the fungal pathogen is spreading across the African continent, an area scientists thought had escaped the worst of the disease.

But Vredenburg and his colleagues found that the disease is already well established in Africa, and that its spread over the past two decades seems to have gone unnoticed in the region. The researchers found that it is likely to become more common, and that amphibian declines and extinctions may already be happening there under the radar.

“Since 2000, Bd has spread throughout Africa and may threaten species across the continent,” Vredenburg said.

Africa is home to about 16 percent of known living amphibian species, but no Bd outbreaks—a disease event in an animal population that resembles an outbreak in humans—have been described in Africa, although the disease is known to occur there.

The researchers said the lack of outbreak reports was likely due to fewer Bd sampling efforts in Africa compared to other continents, rather than a true lack of incidents.

Authors Bounds The study reached its conclusions after analyzing thousands of museum specimens collected from different places in Africa between 1908 and 2013. They also tested skin samples from live amphibians caught between 2011 and 2013, and examined scientific materials from 1852 to 2017.

They found a pattern of Bd emergence in Africa that largely began around the turn of the century. Between 1852 and 1999, they observed a low prevalence of Bd (about 3 percent overall) and a low geographic distribution on the continent.

But after 2000, they documented a sharp increase in prevalence, reaching more than 21 percent in the 2010s. In some countries for which more data was available, the increase was even higher – for example in Burundi, it rose to more than 70%.

“We should be concerned,” Vredenburg said. “This is the first fungal pathogen to cause this level of vertebrate mortality. Although this is not The last of us 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.”

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