White-nose syndrome

WNS is associated with the fungus Pseudogymnoascus destructans (previously Geomyces destructans).

White-nose syndrome (WNS) has not been detected in Australia.

WNS occurs in bats in eastern North America. First documented in New York in the winter of 2006-2007, it has spread rapidly across the eastern United States and Canada, and P. destructans has been detected as far west as Oklahoma. Importantly, P. destructans also occurs on bats in Europe, without disrupting hibernation or causing mass mortalities (i.e. fungus present but not causing white-nose syndrome).

Microchiroptera (insectivorous bats)

White-nose syndrome may be associated with some or all of the following:

• visible white fungus, especially on the bat's nose, but also on the 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% 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 5-10^oC, and ceases growth above 20^oC, it may not survive well in Australia's climate. Bats in Australia's warmer climate do not fully hibernate.

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

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.

Clinical disease develops during hibernation.

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.

If you suspect a bat or group of bats may be infected with WNS:

• take photos
• minimise contact with affected bats
• report your suspicions to Biosecurity Queensland on 13 25 23
• decontaminate all clothing and equipment to reduce the risk of spread to other areas.

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.

It is important that people who 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 clothing and equipment, for example caving gear.

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

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

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