Deadly fungus triggers mass extinction of American bats

Also present in Europe, but strangely harmless here

Hair of a European bat covered with fungal spores (Scanning Electron Microscope Image) © Forschungsverbund Berlin
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Fungal disease has already killed more than one million bats in North America and is still spreading. Now researchers have detected the pathogen in Europe. But here the infection seems to be completely without consequences for the animals. If found, this could be the salvation of American bats already threatened with extinction.

North America has been experiencing dramatic losses of hibernating bats for several years. The numbers of animals that died of "white-nose syndrome" have now exceeded the million mark. The mass extinction so far focused on the northeastern states and has since spread concentric. The disease is triggered by an infection with the fungus Geomyces destructans. The disease is called white-nose syndrome, because the fungus grows in small, white pads mainly around the nose and on the wings. It is one of the cold-loving mushrooms that live preferably on keratinous materials such as dander or hair. In the US, the fungus causes the most severe tissue destruction in animals, leading to death. There is growing concern in Europe that the spread of the pathogen could lead to a similar threat to native bat species.

Mushroom has also been present in Europe for a long time

However, a joint study by researchers from Germany, Switzerland, Hungary and the UK has now shown that the fatal fungus Geomyces destructans is already present in much of Europe. In addition, old records showed that the fungus had been spotted in Germany for at least 25 years on hibernating bats - but without serious consequences: "So far, the fungal infection does not seem to have had a lethal effect on local bat species, " explains project leader Gudrun Wibbelt from the Berlin Leibniz Institute for Zoo and Wildlife Research (IZW).

Same mushroom - other consequences

The research team around Wibbelt analyzed samples from over 350 bat winter quarters in various European countries and found that 21 animals were affected by fungal attack.

Strangely, unlike the US here without serious consequences: "Surprisingly, molecular biological analyzes showed a 100% agreement of the European fungal gene segments compared to those from North America. We must now understand why fungal attack on European bats has not led to death so far as to provide clues to save the American bats and um if necessary, prevent the spread of the fatal fungus from the USA to Europe. Further investigations should help to protect the bat populations in Europe and North America, "says Wibbelt. display

Large mouse-ear bats with fungal colonization on the nose and wings Forschungsverbund Berlin

American bat species threatened with extinction

In the past few winters in America, bats had awakened from hibernation too early, left their cave quarters, and were found dead by the hundreds in the snow outside the caves. Formerly common bat species were decimated in known caves by 80 to 99 percent and are threatened with extinction in the affected regions. This is reminiscent of the also more recently occurring fungal disease "chytridiomycosis", which attacks the skin in the case of frogs and contributes to the global amphibian dying.

There are around 40 insectivorous bat species in Europe, the smallest of which weighs only four grams, the largest with a span of more than 40 centimeters. Most bat species are under serious threat and therefore protected. Bats are a very important part of all habitats, for example, they are responsible for the enormous reduction in harmful insects, which are one of their main food sources. This is of considerable ecological and economic value to agriculture, as it not only reduces the use of pesticides, it also destroys fewer plants of pests.

Currently, in Europe and North America, there is a great deal of interest in clarifying the whitewash

Syndrome worked to understand why European bats seem to be immune to fungal attack.

(Forschungsverbund Berlin, 04.08.2010 - NPO)