Wildlife Health

Common Raven

During spring and summer, the public should be alert to unusual deaths in wild birds, particularly crows, ravens (pictured), black-billed magpies, and blue jays. Unusual deaths in these species could be a sign of West Nile virus. 



Believe it or not, diseases and parasites are a natural part of a healthy ecosystem.

For the most part, wildlife diseases are left to circulate without human intervention.

Today, our ecosystems are under increasing stress.  This stress can increase the impact that some wildlife diseases have on animals, ecosystems, biodiversity, agriculture and even world economies.

Although uncommon, several wildlife diseases (zoonoses) also have the potential to affect people.

Various levels of government are working together to improve our understanding and ability to deal with wildlife health and disease.

The Role of the Ministry of Natural Resources in Wildlife Health

Diseases affect one of Ontario's most valuable natural resources - wildlife. This is why the Ministry of Natural Resources (MNR) is working with other ministries, agencies and stakeholder partners to coordinate the control, monitoring and prevention of certain wildlife diseases and parasites. 

The ministry develops policies and regulations related to wildlife health.  The ministry works with other levels of government, neighbouring provinces and states, interested groups, and members of the public.

It is important to monitor and control disease to:


  • Detect problems early
  • Keep disease and parasites from spreading to new areas
  • Address public safety issues 
  • Conserve wildlife species.

MNR's Wildlife Research and Development Section undertakes research, surveillance and control activities for several diseases as part of Ontario's comprehensive approach to wildlife disease. 

Chronic Wasting Disease


Chronic wasting disease (CWD) is a disease of the central nervous system that affects white-tailed deer, American elk, moose and mule deer. The disease is fatal to these species. Research into the origin and transmission of CWD is ongoing.


There is no evidence to date that CWD exists in Ontario's wild white-tailed deer, elk or moose. (There are no mule deer in Ontario).  There is also no evidence that the disease can spread to people.


MNR, the Ministry of Agriculture, Food and Rural Affairs, and the Canadian Food Inspection Agency (CFIA) monitor deer and American Elk in the wild and on farms and zoos.


In Canada, Chronic Wasting Disease is a reportable disease under the federal Health of Animals Act. All cases must be reported to the CFIA.


The MNR restricts the import of high risk parts of harvested White-tailed Deer and Moose to reduce the risk of CWD entering Ontario.  The CFIA regulates the import and movement of live cervids (members of the deer family) to protect the health of domestic stock.


More information on CWD, Ontario's surveillance activities, or potential response actions, is provided on this website or by contacting your local MNR office.



Rabies exists in almost all parts of the world. It is an infectious disease of the central nervous system and is always fatal unless treated quickly after exposure.


In Canada, the most common carriers of rabies are:


  • raccoons
  • skunks
  • foxes
  • bats


Ontario is a recognized leader in rabies research and prevention. More information on rabies and other wildlife disease research, surveillance and control programs, is available on MNR's Rabies Research and Development Unit website.


Health units and municipalities play key roles in Ontario's rabies control program.  For information on human health, please contact your local public health unit


Avian Influenza


Avian influenza is an infection of birds. Some types of avian influenza are quite common in wild birds and are not dangerous.


Avian influenza can, however, be very contagious among domestic birds.  Avian influenza can have major impacts on poultry such as chickens, ducks and turkeys. 


Some types of avian influenza can have serious impacts on the movement of animals for agriculture. In Canada, these strains of the virus are reportable to the Canadian Food Inspection Agency under the federal Health of Animals Act.

Anyone noticing dead wild birds, particularly waterfowl or significant numbers of any type of dead wild birds in one location, should contact the Canadian Co-operative Wildlife Health Centre at 1-866-673-4781.


More information on avian influenza is available on the Canadian Food Inspection Agency website and on the ServiceOntario Bird Flu Information website.


Lyme Disease


Lyme disease is an infection caused by a corkscrew-shaped bacterium (Borrelia burgdorferi). In Ontario, these bacteria are spread by the bite of the Black-Legged Tick (Ixodes scapularis).

Due to potential human health implications, the Ministry of Health and Long-Term Care has the provincial lead for surveillance, prevention and control of this disease.


Lyme disease bacteria have been found in ticks from some areas of Ontario. Lyme disease-carrying ticks are most common along the north shore of Lake Erie, particularly near Long Point, Turkey Point and Rondeau Provincial Park. They have most recently been found in the St. Lawrence Islands National Park area.  However, there is no evidence to suggest that ticks are restricted to these locations.


People who are active outdoors are likely to come in contact with ticks.  After spending time in tall grass or forested areas, you should shower, check yourself daily for ticks, and watch for the red rash that signals a tick bite.


For more information on Lyme disease prevention and treatment, please consult the Public Health Agency of Canada's Lyme Disease Fact Sheet, the Ministry of Health and Long-Term Care Lyme disease website or contact your local public health unit.



White Nose Syndrome


White nose syndrome is a fatal condition of bats named for the white fungus which grows on the face, ears and wings of affected animals.  Other signs include poor body condition (emaciation and dehydration) as well as behavioural changes such as bats flying in daylight during winter. The cause of the syndrome is still under investigation.  


In March 2010, white nose syndrome was detected for the first time in Ontario.


To better assess bat health in Ontario, the Ministry of Natural Resources and the Canadian Cooperative Wildlife Health Centre are monitoring bat populations within caves and abandoned mines.


More information, including the current status of white nose syndrome in Ontario, is available at our Bats and White Nose Syndrome web page.



West Nile Virus

West Nile virus occurs in a wide range of bird species, and occasionally in some mammals, including horses and humans. Generally, wildlife is not significantly affected by the West Nile virus (WNv), and infection of wildlife is not a cause for concern.

West Nile virus is transmitted to people by mosquitoes. There is no way to predict how serious human infection by West Nile virus will be in any given year.

Due to human health implications, the Ministry of Health and Long-Term Care has the provincial lead for surveillance, prevention, and control of this disease.


During spring and summer, the public should be alert to unusual deaths in wild birds, particularly American Crows, Common Ravens, Black-billed Magpies, and Blue Jays.  If you notice dead birds, contact your local public health unit.

More information is available on the Ministry of Health and Long-Term Care's West Nile virus website.

Canadian Cooperative Wildlife Health Centre is a university-based organization which works to reduce ecological and socio-economic impacts of wild animal diseases.


Canada's National Wildlife Disease Strategy is a disease response and management plan that aims to minimize the impacts of wildlife diseases. The strategy will help to coordinate response across provinces.