Get the Latest on Anthrax Outbreaks in Bison

Current status

There is no active anthrax outbreak at this time. 

Key activities

None at this time.

Management actions which could affect you

None at this time.

Map of affected area

None at this time. 

Health precautions

Though extremely rare, anthrax can be transmitted to humans through direct contact with infected animals, carcasses, or animal parts (e.g. meat, hide, hair). The illness does not seem to spread from person to person. Take these precautions to stay safe:

  • Do not approach, hunt, or eat Bison in the Slave River Lowlands (see map above) until otherwise indicated by ECC
  • If you see a dead bison, do not go near it, do not touch it, and do not allow domestic animals to do so either. Report dead bison observations immediately to 1-867-872-6438
  • Do not turn up soil nearby where bison were
  • Anyone who has been exposed to anthrax spores but is not yet sick should be treated with antibiotics and a few doses of the vaccine to prevent infection. If for any reason you believe you may have interacted with a sick bison or soil surrounding them,, call your local health centre immediately.
  • If you’re on-the-land in the area, stay aware of your surroundings, follow any signage or instructions, and stay out of areas which are closed due to anthrax response.

Report sick or dead bison (or other large mammals):

  • Call the Bison Control number at 1-867-872-6438 to report any dead bison you find to Environment and Climate Change immediately. Do not approach carcasses.
  • Call 1-867-872-6438 as soon as you can if you observe bison who appear sick. For example:
    • Having difficulty walking
    • With foamy or bloody looking discharge coming from their nostrils or anus
    • With significant swelling or distension of abdomen

What you can expect during response

  • Area or highway closures – stay up-to-date by using the NWT Highway Conditions Map, following social media, and staying up to date with local news.
  • Individuals in hazardous materials suits
  • Smoke or fire if a carcass site is near your community or along your travel route.


Anthrax outbreaks can occur in bison populations (Mackenzie, Slave River Lowlands, and Nahanni herds) during the summer months.

Anthrax is a bacterial disease caused by inhaling or ingesting anthrax spores, which can be found in soil which has been contaminated by the spores. Bison can inhale the spores when wallowing in dust baths or ingest them while grazing and become infected. 

The disease is fatal for bison. Though rare, it can also occur in other mammals, including humans.

While there have been no recent cases of human exposure or illness documented in the NWT, anthrax can cause an infection should a person come into direct contact with infected bison or bison parts. It is important to take appropriate precautions to prevent exposure.   

Signs and Symptoms of Anthrax in Bison

Bison with anthrax may exhibit any of the following signs:

  • Found dead – often animals appear bloated and may be lying on their side in a sawhorse stance
  • White or bloody foam discharge from nostrils
  • Appearing depressed or unresponsive to stimuli
  • Stopping eating, or overfeeding and stop ruminating
  • Appearing lame or having a stiff-legged gait.
  • Swelling below the skin
  • Refusing to get up when people, aircraft, or vehicles approach

Signs and Symptoms of Anthrax in Humans

Anthrax occurrence in humans is extremely rare. You can only get anthrax by inhaling the spores, eating contaminated meat, or having the spores come in contact with your skin, particularly an open wound or mucosa. People with anthrax are not capable of infecting others.

Anyone who has been exposed to anthrax spores but is not yet sick should be treated with antibiotics and a few doses of the vaccine to prevent infection; please contact your local health centre

 Signs and symptoms of anthrax can include the following;

  • Cutaneous (skin) anthrax which begins as a raised bump on the skin that  becomes a blister, and then a painless ulcer with a black area in the center. Lymph nodes near the wound may become swollen. Skin anthrax is easily treated with antibiotics.
  • Intestinal anthrax is very rare. It begins with nausea, loss of appetite, vomiting, and fever. Those symptoms are followed by abdominal pain, vomiting of blood, and severe diarrhea. Early antibiotic treatment is important if you have intestinal anthrax.
  • Inhalation anthrax begins with flu-like symptoms (cough, fever, muscle aches). These symptoms may last two to three days, and then appear to go away for one or two days. Then the illness can come back, resulting in severe lung problems, difficulty breathing, and shock. Unless it’s treated, inhalation anthrax can be very dangerous – it’s fatal in up to 90 percent of cases.

Response plan

When Anthrax is suspected or detected in Bison, an Incident Management Team is mobilized to respond. 

Rapid detection and disposal of dead infected bison and keeping people away from affected bison are the objectives.

This minimizes the release of anthrax spores into the soil, protects bison populations, and protects public health and safety.

The following actions will be taken:

  • Aerial and ground surveillance for bison carcasses
  • Rapid response to carcass sites to sample affected animals
  • Incineration or chemical treatment of bison and surrounding grass areas to prevent the spread of spores
  • Management of wildfire risks due to burning required during response
  • Public information will be provided to mitigate risks for people