Bats and public health

Contrary to popular belief, few parasites and diseases of insectivorous bats (those bats that eat only insects) pose any threat to human health.

• When bats inhabit a building, they pose little threat to the safety of people or other animals.
• Their nocturnal habit of feeding on insects means they seldom interact with humans.
• There are few valid accounts of bats attacking people. Even rabid bats rarely become aggressive.

Some diseases of potential concern are discussed below:

Bat Diseases

Histoplasmosis

Histoplasmosis is a very rare respiratory disease in humans caused by a fungus that grows well in soils enriched with animal droppings.

In North America human cases are known primarily from the humid areas in the Mississippi and St Lawrence river valleys in association with accumulated guano of pigeons, starlings, and bats. However, the fungus requires ongoing warm, moist conditions and is rarely found in Alberta. There is only one report of the fungus in the province.

In 2003 a cluster of four human cases was documented in the Edmonton area. All individuals worked together on a golf course and were involved in a project to replace some sod. The sod originally came from British Columbia. Apparently there were fungus spores either in the sod or in the ground where the new sod was lain.

Rabies

Rabies is an acute infectious disease of the central nervous system. It has been identified in a few bat species throughout Canada and the United States. In Alberta, testing of bats for rabies over many years indicate that the infection rate in bats is extremely low across the province.

It should be noted, however, that much information about rabies has been sensationalized and misrepresented. While individual bats should be handled cautiously, widespread fear and persecution of bats is unwarranted.

A summary of what is known about rabies in insectivorous bats can be found at:

• Bats and Rabies

Rabies Risk and Prevention

Alberta Bat-Related Rabies Infection Cases

Rabies is an extremely rare disease in Alberta. Since 1985, there have been two cases of human rabies in Alberta. Both occurred following bat exposures where the exposed person did not seek medical attention for preventative treatment following exposure to the bat.

• In July 1985, a man apparently contracted rabies from a big brown bat in northern Alberta. He did not seek treatment and did not receive rabies preventative vaccine before or after the exposure. In December 1985, the man died of the disease.
• In 2007, a case of bat-related rabies occurred in central Alberta. Similar to the first case, the initial encounter with a bat was not reported to a health care provider and the person later died from the infection.

Bats usually avoid people but will bite in self defence. Less than 1% of bats have rabies, however, as a precaution, you should always avoid direct contact with bats.

Suspected or confirmed contact with a person

Contact Alberta Health Services and/or a physician to report the incident and receive medical advice as soon as possible. Post-exposure treatment may be required.

Contact Alberta Health Services at:

• Health Link at 811 or toll-free across Canada at 1-866-408-5465
• MyHealth.Alberta.ca - Rabies

Contact the Rabies Hotline at:

• Rabies Hotline – 1-844-427-6847

If there was suspected or confirmed contact with a domestic animal

The animal’s owner should contact a veterinarian for instructions as soon as they can. If available, the bat may be sent away for rabies testing.

Learn more about rabies in animals, and how to respond if you suspect your pet has been exposed, see:

• Rabies in Animals

For more information about what to do if you find a bat, visit:

• Bats in Alberta – What to do if you find a bat

Rabies Vaccine

An effective rabies vaccine is available to prevent the disease in humans and is effective for both pre-exposure and post-exposure prophylaxis. Rabies is nearly 100% preventable if timely treatment is sought following a rabies exposure.

For more information on the rabies vaccine for humans see preventing rabies infection.

Bat Parasites

Ectoparasites (Bat bugs)

Ectoparasites, primarily bat bugs (Cimicidae), that live on bats only try to bite people if there are no bats to feed on (for example, AFTER control measures to eliminate bats have been taken).

Bat bugs rarely feed on humans in Alberta and, while an annoyance, they are not considered dangerous since they are not known to transmit any diseases.