White-nose syndrome overview

Associated with the fungus Pseudogymnoascus destructans (previously Geomyces destructans)

White-Nose Syndrome (WNS) is a disease that causes mass mortality of hibernating insectivorous bats (microbats) North America. Death is associated with an infiltrative fungal infection of the muzzle and other parts of the body that disrupts normal hibernation.

P. destructans has not been detected in Australia. WNS occurs in bats in the eastern United States and Canada.

Importantly – P. destructans also occurs on bats in Europe without disrupting hibernation or causing mass mortalities (i.e. fungus present but not causing WNS).

WNS may be associated with some or all of the following:

• visible white fungus, especially on bat’s nose, but also on wings, ears or tail
• bats flying outside during the day in temperatures at or below freezing
• loss of body fat reserves
• bats clustered near entrances of hibernacula (places bats hibernate)
• dead or dying bats on the ground or on buildings, trees or other structures.

In some hibernacula, 90-100% percent of bats have died, leading to significant declines in insectivorous bat populations.

It is unclear how P. destructans might affect Australian bat populations. It may or may not be associated with mass mortalities, as there are significant differences in Australia's climate and bat ecology. As P. destructans grows best between 5 and 10C and ceases growth above 20C it may not survive well in Australia's climate. Also bats in Australia's warmer climate don't fully hibernate.

The mass bat mortalities that characterise WNS in North America have not been reported in Australia.

Although the appearance of white fuzz on the muzzle, ears and wings is suggestive of the fungal infection associated with WNS, other incidental superficial fungal infections can look very similar.

Histopathology (microscopic examination of tissues) shows infiltration of the fungus into the deeper layers of the skin.

Fungal culture and molecular genetic tests (polymerase chain reaction (PCR) and sequencing) are used to identify the fungus.

First documented in New York in the winter of 2006-2007, WNS has spread rapidly across the eastern United States and Canada.

The fungus associated with WNS has also been detected on bats in multiple countries in Europe without causing the mass mortalities characteristic of WNS.

The fungus associated with WNS is primarily spread by direct bat-to-bat contact. Humans have been implicated in the spread of the disease in the United States. P. destructans can persist in the environment and can be spread on clothing, shoes, caving gear or other equipment.

It is important that people that explore caves or work with microbats returning or entering Australia from overseas are aware of the risk of carrying the fungus into Australia on their caving gear.

The risk of introducing or spreading WNS can be reduced by:

• avoiding contact with potentially affected sites, equipment, or bats themselves
• cleaning and disinfecting clothing and equipment used in bat habitats.

Decontamination protocols and other measures can minimise transmission by humans.

Australian cavers and those working with bats should be aware of WNS and report any suspect cases to animal health authorities.

No - no direct human health risk has been identified.