Recent information from the Australian Chief Veterinary Officer to ASF
By NICHOLAS WHITE ASF Conservation Commissioner
The Chief Veterinary Officer, Dr Mark Schipp, has appealed to the Australian speleological community (ASF) to be aware of the debilitating fungal ‘White Nose Syndrome’ (WNS) in bats.
Currently neither the syndrome nor the fungus has been identified in Australia. However if WNS were to occur here it could have similarly devastating effects on Australian bats as those in the US and Canada. Occasionally cave dwelling bats are submitted to animal health authorities in Australia due to unexplained deaths or illness, and these are now tested to rule out infection with WNS fungus.
Dr Schipp sees speleologists as having a vital role to play in preventing the entry of the fungus that causes WNS to Australia as we will be amongst the first to observe the disease if this happened. In recognition of this position, he has provided the article below which has the most up to date information about the disease, decontamination protocols and steps to take if evidence of the disease is observed.
Cavers and cave managers travelling internationally should avoid bringing in equipment used overseas, especially from areas where WNS is known.
We should also be aware of and observe the decontamination protocols. When hosting international cavers and cave managers the same protocols should be observed.
The issue of decontamination and cross contamination between caves and caving areas has been part of the ASF Code of Ethics for a very long time. Some of the spread of WNS in NE America has been due to bat movement between sites, but there are other instances where humans are implicated in the fungus spread. It is important to thoroughly clean ALL your cave gear between cave trips.
The following article (pp8-9) from Federal Department of Agriculture, Australian Government, also refers to Histoplasmosis. This fungus does occur in Australian bat caves, especially dry dusty ones.
Cavers should be alert to the occurrence of chest infection and pneumonia shortly after visits to such caves. Australian bat lyssavirus occurs in micro bats and flying foxes. Inadequate knowledge exists regarding infectious status of cave dwelling bats and therefore handling bats should be avoided.
As the ASF Conservation Commissioner and microbiologist, I am a member of the Bat Health Focus Group of the Australian Wildlife Health Network and therefore receive their emails and alerts. I will ensure that appropriate information is communicated.
White Nose Syndrome in bats
Department of Agriculture, Australian Government | May 2014
IN 2007 a new disease was seen in cave hibernating bats in the US state of New York, and was retrospectively suspected to have been present the previous year.
The disease was called ‘White Nose Syndrome’ (WNS) because of the fluffy white growth of fungus that appeared on the muzzle, ears and wings of affected bats. Since then, the disease has spread to 22 US states and five Canadian provinces and had devastating effects on bat populations in affected caves with up 90% of the population dying.
The disease affects microbats (small insectivorous bats) as they hibernate in caves. Bats with WNS may die due to depletion of fat stores associated with more frequent rousing from hibernation; cold exposure if they leave the cave to search for food in freezing conditions; or metabolic disruption due to the damage to the wing membrane.
The causative agent is a fungus called Pseudogymnoascus (formerly Geomyces) destructans. The fungus prefers to grow in cold conditions; caves with affected bats typically have an ambient temperature of 2-14°C. The fungus will not grow above 20°C.
Bats experience decreased body temperature and immune function during hibernation, which facilitates infection by the fungus. They also congregate in very close proximity while hibernating, which increases transmission between bats and contamination of the cave environment. At other times of the year, body temperature is consistently above the temperature tolerated by the fungus and the disease is not seen.
In Europe, hibernating bats with visible fungal growth of P. destructans have been detected, but the fungus has not been associated with mass mortalities of bats. There is evidence to suggest that the fungus has been present since the 1980’s or earlier.
It is possible that bats in Europe have developed resistance due to a long evolutionary relationship with the fungus. In the USA, bats do not have this resistance and this suggests it may have been recently introduced there. The disease was first seen in the USA in a popular show cave, increasing suspicion that the fungus may have been introduced from Europe.
The spread of WNS in North America is believed to occur mainly by movements of bats between caves during their active season. However, the distances between known infected caves and newly infected caves are sometimes larger than could occur by this route, suggesting it may have been carried by people, for example those visiting caves.
The fungus can be carried on contaminated equipment, clothing and footwear, and this is the most likely potential route of entry of the fungus into Australia.
The fungus has been found to survive in the environment in caves for long periods even when bats are not present.
Speleologists have an important role to play in preventing WNS entering Australia and detecting the disease if it did occur here. Below is some information about decontamination of equipment, and how to report suspected disease outbreaks.
Decontamination of equipment
The best way to prevent entry of WNS on caving equipment is to avoid bringing equipment that has been used overseas into Australia. This applies equally to Australians visiting caves in other countries (particularly in Europe and North America) and to overseas tourists visiting caves in Australia.
Decontamination of clothing, foot wear and equipment can be attempted but this may not completely remove the risk that WNS could be brought into Australia. Items that have been used in caves where WNS is known or suspected to occur are at high risk of bringing the disease into Australia and should not be used in Australian caves, even if they have been decontaminated.
Decontamination procedures for equipment have been published in the USA and can be downloaded from http://www.whitenosesyndrome.org/topics/decontamination (‘Revised Decontamination Protocol’ and ‘Supporting Decontamination Documentation for Cavers’).
A brief summary of these procedures is provided below, however please refer directly to the online protocol documents for more detailed information.
Please note: There is no information confirming that safety equipment will remain as effective after decontamination, so careful thought is required when deciding whether to attempt decontamination of this equipment.
Select equipment that is easy to clean, and preferably will not be damaged by cleaning.
Remove outer garments and footwear as you leave the cave.
Thoroughly scrub and remove sediment/dirt from clothing, footwear and equipment immediately upon emerging from the cave, as these reduce the effectiveness of the decontamination procedure.
Once fully scrubbed and rinsed, seal clothing, footwear, and equipment in a plastic bag or container for transport. A clean change of clothing is recommended. Store exposed gear separately from clean gear, and avoid contamination of vehicles.
Later, clothing should be machine or hand-washed using a conventional cleanser and rinsed thoroughly.
All clothing, footwear and equipment that can be immersed in water should be submersed in water at a temperature of at least 50°C for a minimum of 20 minutes followed by air drying to kill any remaining fungus. Some effective disinfectants are available, but these are harsh chemicals and may damage some items. Refer to the decontamination procedures (links above) for more information.
It is recommended that equipment that cannot be immersed in water (e.g. cameras and electronics) only be taken into potentially contaminated overseas caves when absolutely necessary.
In these instances refer to the decontamination procedures for more information about how to use a sealed disposable plastic container (such as a plastic bag) to minimise contamination.
Cleaning and decontamination of clothing and equipment between caves visited within Australia may also assist to reduce the spread of existing infectious diseases, and to prevent the spread of WNS were it to be introduced into this country.
How to report signs suspicious of WNS in Australia
We do not know exactly how WNS would behave if introduced into Australia. However, groups of live bats with fluffy, white growths on the muzzle, wings or ears, or sudden death of large numbers of bats in or around a cave are both highly suspicious. If you observe either of these situations, record the date and location, and take photographs if possible.
Note: While WNS has no known human health implications, bats should only be handled by people who are appropriately vaccinated and experienced in handling bats, due to the risk of exposure to Australian bat lyssavirus (see below).
To report bats with suspected WNS or other unusual signs, contact the state or territory department of agriculture or primary industries.
The Australian Wildlife Health Network (soon to become Wildlife Health Australia) maintains a list of wildlife coordinators in each state or territory department or can accept reports directly and pass them to the appropriate person for further investigation (details below).
Alternatively, call the Emergency Animal Disease Watch Hotline on 1800 675 888. Single dead bats with fungal growth are probably in the process of normal decomposition and do not need to be reported, however if in doubt please call for advice.
Emergency Animal Disease Watch Hotline: 1800 675 888
Link to the Australian Wildlife Health Network wildlife coordinator contacts:
Further information and links
The Australian Wildlife Health Network maintains a fact sheet on WNS, available on their website:
The United States Geological Survey website has the most up to date information on the situation in the US and links to research on this disease:
<http://www.nwhc.usgs.gov/disease information/white-nose syndrome/>
The White-Nose Syndrome.org website also has information and links to research into this disease. The recommended decontamination protocols are also published on this website and are updated from time to time.
PUBLIC HEALTH NOTES
There is no evidence that White Nose Syndrome can affect humans; however, there are some other diseases associated with bats that can affect people. Speleologists and others in close proximity to bats face a higher risk of infection.
Histoplasmosis is caused by a fungus, Histoplasma capsulatum, which is often associated with bird and bat droppings. People may become infected when they inhale the spores in dusty, contaminated environments, particularly in enclosed spaces such as caves.
Most people do not develop obvious disease, but severe disease can be seen in those with weakened immune systems. Initial signs are often similar to flu. The best prevention is to avoid inhaling dust in potentially contaminated areas.
Australian bat lyssavirus is related to rabies virus and has caused the deaths of three people in Australia since it was identified in 1996.
It has been found in both microbats and flying foxes in most states and territories. People become infected from bites or scratches from affected bats. You should avoid handling bats, particularly those that appear sick, unless you have current immunisations against rabies and are experienced at handling bats.
There are rare reports of the related rabies virus being spread from bats to humans in caves in the US, probably by inhalation of aerosolised bat urine or faeces, however this has never been reported to occur in Australia due to Australian bat lyssavirus.
Note: Hendra virus may also be carried by flying foxes, however there is no evidence of direct transmission from flying foxes to humans. A small number of people have become infected with Hendra virus following close contact with infected horses.
For more information about any of these diseases, visit your GP or contact your state public health authority. If you believe you have been bitten or scratched by a bat, seek medical attention URGENTLY.
Immediately wash the bite or scratch site thoroughly with soap and copious water for approximately 5 minutes and apply a virucidal antiseptic solution such as povidone-iodine or alcohol.
Bat saliva in the eyes or mouth should be rinsed out immediately and thoroughly with water.