Fungal disease that kills frogs, toads and salamanders worldwide | Earth



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An international study determined that a fungal disease – called chytridiomycosis – had caused a dramatic decline in the population of more than 500 species of amphibians – mostly frogs, but also toads and salamanders – including 90 extinctions .

In the past 50 years, the deadly disease that has been eating away at amphibians has completely eliminated some species, while causing more sporadic mortality in other species.

Little frog with big black eyes hanging on a branch of tree.

The Common Mistfrog of Queensland is one of the frog species whose populations have declined due to chytridiomycosis. Image via Lee Skerratt / U. Melbourne.

According to the research, published March 29, 2019, in the newspaper Science, chytridiomycosis is present in more than 60 countries – the most affected regions of the world are Australia, Central America and South America.

Ben Scheele of the Australian National University is the lead author of the study. Scheele said in a statement:

This is the largest loss of biodiversity recorded due to a disease.

Cutaneous cells resembling grayscale tiles with round tubes glued to each side.

A photo using a scanning electron microscope shows an infected frog with fungal tubes crossing the surface of the skin. Image via Lee Berger / U. Melbourne.

Chytridiomycosis, caused by chytrid fungi, is probably native to East Asia, but is now known to be present in more than 60 countries.

Lee Berger, an associate professor at the University of Melbourne, who discovered chytridiomycosis in 1998, is co-author of the new study. She said that when chytridiomycosis is introduced into a sensitive amphibian population, its effects are sudden and devastating.

The fungus invades the skin of adult amphibians and lives in the cells of the epidermis and disrupts the functions of the skin.

Unlike mammals, amphibians absorb water and electrolytes through their thin, permeable skin, but chytridiomycosis inhibits this process. Frogs lose potassium and sodium until their blood levels are too low and their heart begins to malfunction. They become lethargic and die.

Frog with tan and black pattern, eyes with vertical pupils, sitting on a rock.

The Yellow-footed Mountain Frog was listed as endangered in 2014 after the loss of more than 90% of the population. Image via Isaac Chellman / NPS / Flickr.

Scheele said the unprecedented number of areas of decline of the chytrid fungus was one of the world's most harmful species. Scheele said:

Highly virulent wildlife diseases, including chytridiomycosis, contribute to the sixth mass extinction of the Earth. The disease we studied has caused massive extinctions of amphibians worldwide. We lost really amazing species.

The researchers say that globalization and wildlife trade are the main causes of this global pandemic and allow the spread of the disease. Scheele said:

Humans are moving plants and animals around the world at a faster pace, introducing pathogens into new areas.

Conclusion: A new study has shown that a fungal disease – called chytridiomycosis – has caused a dramatic decline in the population of more than 500 species of amphibians – mainly frogs – including 90 extinctions.

Source: Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity>

Via the Australian National University

Eleanor Imster

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