Bats and Human Health

    (from Queensland Health Version 7 published 15/01/2016)

What is the risk to humans from bat diseases?

Bats and flying foxes may carry bacteria and viruses which can be harmful to humans but the risk of infection is low. 

People who are not trained and vaccinated should not handle bats.

If you find an injured bat or flying fox, do not attempt to help the animal yourself or touch it in any way.

Contact the RSPCA (1300 ANIMAL) or your local wildlife care group/rescuer/carer, or the Department of Environment, Tourism, Science and Innovation (1300 130 372) for assistance.

What diseases do bats carry?

Australian bat lyssavirus (ABLV) is a virus that can be spread to humans by the saliva of infected bats when the saliva comes in contact with mucous membranes or broken skin, or through bat bites or scratches. Infection with ABLV causes a rabies-like disease in humans that is usually fatal. However, there have been only three documented cases of ABLV infection in humans. All three of these were in Queensland.

There are two simple steps to avoid ABLV disease:

•  Don't handle bats unless you are trained in handling them, are using protective equipment and are vaccinated against rabies. Most bat bites and scratches in Queensland occur when people try to help sick or injured bats as they are difficult to handle, they become agitated and they have sharp teeth and claws.
•  If you are bitten or scratched by a bat, wash the wound thoroughly, apply antiseptic and seek immediate medical advice about receiving injections to protect you against ABLV.

Hendra virus can be transmitted to humans via close contact with the body fluids of infected horses. The natural host for Hendra virus is the flying fox. Horses may be infected by eating food recently contaminated by flying fox urine, saliva or birth products. There is no evidence that the virus can be spread directly from flying foxes to humans or through the faeces of flying foxes to humans. Testing of bat carers who have frequent contact with flying foxes has shown no evidence of exposure to the virus.

Histoplasmosis is a very rare lung infection. Bats, dogs, cats, cattle, horses, rats and other animals can be infected and can excrete the organism in their droppings. People who have contact with bats or bat caves, for work or recreation, should avoid exposure to dust in environments likely to be contaminated with bat droppings. It is advisable to spray potentially contaminated areas with water before cleaning. People working in these areas should also use protective equipment such as face masks, gloves and overalls.

Leptospirosis is a bacterial disease transmitted via the urine of infected animals. In very rare cases, leptospirosis can be fatal to humans. Although rodents and cattle are the main carriers of this disease, bats may also be infected.

Leptospirosis occurs most commonly in people who are exposed to the bacteria during their work, for example farmers, veterinarians and meat workers. The most effective way to avoid getting leptospirosis from bats is to prevent bat urine from coming into contact with broken skin or your eyes, nose or mouth. Hands should always be washed after caring for bats.

Salmonella and other bacteria that cause gastroenteritis may be found in animal faeces. Most cases of salmonella infection in Queensland are caused by eating undercooked or raw food contaminated with salmonella bacteria. The infection may also be acquired from close physical contact with animals such as dogs, poultry and cattle. It is assumed that some flying foxes may also carry the bacteria. Hands should always be washed after handling bats or their faeces or urine.

Rainwater tanks and swimming pools

The use of rainwater tanks for household use is an established and relatively common practice in Australia, particularly in rural and remote areas. There is little reported illness from rainwater consumption and rainwater tank risks can be easily managed. It’s particularly important to manage the risks where there are people with significantly reduced immunity systems. 

ABLV cannot be contracted from drinking or using water from rainwater tanks that is contaminated with bat faeces. For households using rainwater for food preparation and drinking, the risk of getting a gastro illness from bat faeces is no different than for other animals, including birds. 

A fact sheet on roof-harvested rainwater is available from Queensland Health:
https://www.health.qld.gov.au/__data/assets/pdf_file/0025/444427/factsheet-rainwater.pdf

Current recommendations on managing rainwater quality can be found in the Department of Health’s Guidance on use of rainwater tanks:
http://www.health.gov.au/internet/main/publishing.nsf/Content/ohp-enhealth-raintank-cnt.htm

For advice on identifying and managing risks to human health arising from water on rural properties in Queensland please see the Safe Water of Rural Properties:
https://www.health.qld.gov.au/publications/public-health/industry-environment/environment-land-water/water/safe-water-rural-properties.pdf

Health risk from domestic swimming pools affected by bat faeces can be appropriately managed by maintaining effective pool disinfection. This involves regular backwashing of your pool filter, keeping your pool filter running every day to keep the water clear, maintaining free chlorine levels of around 2 milligrams per litre (or parts per million) and keeping pH between 7.2 and 7.8. Advice on pool maintenance can be obtained from your local pool store.

Key Points:

Australian Bat Lyssavirus (ABVL) is a bat-borne virus closely related to the rabies virus and can be spread to humans by the saliva of infected bats when the saliva comes in contact with mucous membranes or broken skin, or through bat bites or scratches. Aerosol transmission in humans has not been proven in the natural environment.

ABLV infection in humans is rare; there have only been three cases in Australia that occurred in 1996, 1998 and 2013 (all were fatal).

The best protection against being exposed to the virus is for members of the public to avoid handling any bat (dead or alive).

Anyone bitten or scratched by a bat should seek medical advice immediately, even if they have been previously vaccinated against rabies.

Proper cleaning of a wound is very important for reducing risk. If bitten or scratched, people should immediately wash the wound thoroughly with soap and water for at least five minutes. If available, an antiseptic with anti-virus action such as iodine or alcohol should be applied after washing.

Anyone who has been bitten or scratched by a bat will require a series of injections to prevent infection, regardless of how long ago the bite or scratch occurred. People previously vaccinated against rabies still need a (smaller) series of injections. No person who has received post-exposure prophylaxis (vaccinations) has developed clinical disease.

Anyone who comes across an injured bat should contact the Department of Environment, Tourism, Science and Innovation, RSPCA or a local wildlife rescuer/carer.

There is no evidence of ABVL being transmitted to humans from an animal other than a bat.

The use of rainwater tanks for household use is an established and relatively common practice in Australia, particularly in rural and remote areas.  ABLV cannot be contracted from drinking or using water from rainwater tanks that is contaminated with bat urine or faeces.

Anyone who requires further information should contact their local doctor or nearest public health unit or the 13HEALTH information line (13 43 25 84).

Queensland Health has fact sheets available on the internet regarding Bats and Human Health, ABLV and the use of rainwater tanks.

For more information

For further information about bats and human health, contact your local public health unit or the 13 HEALTH information line (13 43 25 84).