Deadly amphibian fungus has its origins in East Asia

July 03, 2018

Batrachochytrium dendrobatidis (Bd), known as chytrid fungus, has long been known to cause the decline and extinction of numerous species of frogs, toads, salamanders and other amphibians on several continents.

Chytrid is found around the world, but until recently it has been unclear where the pathogen originated. New research has now traced its source to East Asia.

The results were published in the journal Science. Researchers at Imperial College London and several partners, including the Norwegian University of Science and Technology's NTNU University Museum, carried out the study.

Enhanced biosafety recommended

The researchers highlight the need for more stringent biosafety guidelines across national borders, including a possible ban on trade in amphibians as pets to ensure the survival of vulnerable species.

"Biologists have known since the 1990s that Bd is behind the decline for many amphibian species. But until now, we haven't been able to identify exactly where it came from," says first author Simon O'Hanlon of Imperial College London.

"In our article we solve this problem and show that the lineage that has caused this devastation can be traced back to East Asia," he says.

Chytrid spreads rapidly in the wild and travels from animal to animal. The fungus causes catastrophic mortality and decline in some species, while others are less affected.

The fungus causes a disease called chytridiomycosis. The disease attacks the animal's skin, which affects its ability to regulate water and electrolyte levels and leads to heart failure.

International cooperation

In this latest study, 38 institutions formed an international team that gathered pathogen samples from all over the world. They sequenced the genomes of the samples and combined the new data with the genomes of previous Bd studies to make a collection of 234 samples.

The researchers analysed the data and looked at differences between the genomes. From the samples, they identified four main genetic lineages of the fungus, of which three were found globally. A fourth line was found only in Korea, on frogs that were native to the region.

Commercial pet trade spreads infectious agent

The researchers' finding supports the hypothesis that instead of dating back thousands of years, as previously thought, the disease range has greatly expanded only in the last 50 to 120 years. This coincides with the rapid global expansion of intercontinental trade.

The researchers believe that human movement of amphibians through the pet trade has directly contributed to spreading the pathogen around the world. They add that the paper provides a strong argument for banning trade in amphibians from Asia, due to the high risk associated with exporting previously unknown strains of chytrid out of this region.

The group highlights the threat of another amphibian pathogen that also emerged from Asia (B. salamandrivorans or BSal), which affects salamanders in Europe. The spread of this pathogen is also connected to the global trade in pet amphibians from Asia.

NTNU contribution to study

"The NTNU University Museum contributed to the study by sequencing the genes of frogs infected by the chytrid bacteria found in the museum collections," says associate professor Michael D. Martin in NTNU's Department of Natural History.

Martin notes that the museum's scientific collections provide valuable historical material that allows researchers to look back in time and carry out genetic studies of evolution. These collections are also an extremely valuable source of genetic information from places that are otherwise difficult to travel to and gather fieldwork samples from.
-end-


Norwegian University of Science and Technology

Related Fungus Articles from Brightsurf:

International screening of the effects of a pathogenic fungus
The pathogenic fungus Candida auris, which first surfaced in 2009, is proving challenging to control.

Research breakthrough in fight against chytrid fungus
For frogs dying of the invasive chytridiomycosis disease, the leading cause of amphibian deaths worldwide, the genes responsible for protecting them may actually be leading to their demise, according to a new study published today in the journal Molecular Ecology by University of Central Florida and the Smithsonian Conservation Biology Institute (SCBI) researchers.

Researchers look to fungus to shed light on cancer
A team of Florida State University researchers from the Department of Chemistry and Biochemistry found that a natural product from the fungus Fusicoccum amygdali stabilizes a family of proteins in the cell that mediate important signaling pathways involved in the pathology of cancer and neurological diseases.

The invisibility cloak of a fungus
The human immune system can easily recognize fungi because their cells are surrounded by a solid cell wall of chitin and other complex sugars.

Taming the wild cheese fungus
The flavors of fermented foods are heavily shaped by the fungi that grow on them, but the evolutionary origins of those fungi aren't well understood.

Candida auris is a new drug-resistant fungus emerging globally and in the US early detection is key to controlling spread of deadly drug-resistant fungus
Early identification of Candida auris, a potentially deadly fungus that causes bloodstream and intra-abdominal infections, is the key to controlling its spread.

Genetic blueprint for extraordinary wood-munching fungus
The first time someone took note of Coniochaeta pulveracea was more than two hundred years ago, when the South African-born mycologist Dr Christiaan Hendrik Persoon mentioned it in his 1797 book on the classification of fungi.

How a fungus can cripple the immune system
An international research team led by Professor Oliver Werz of Friedrich Schiller University, Jena, has now discovered how the fungus knocks out the immune defenses, enabling a potentially fatal fungal infection to develop.

North American checklist identifies the fungus among us
Some fungi are smelly and coated in mucus. Others have gills that glow in the dark.

Tropical frogs found to coexist with deadly fungus
In 2004, the frogs of El Copé, Panama, began dying by the thousands.

Read More: Fungus News and Fungus Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.