It remains safe to visit Wood Buffalo National Park during an anthrax outbreak hitting bison in remote areas of the northern park/Hans Pfaff, NWT Tourism

Wood Buffalo National Park is grappling with an anthrax outbreak in northern Canada.

Parks Canada says that the outbreak is in remote areas of the Northwest Territories/Alberta park and “risk levels to the public are very, very low” and so road-accessible visitor facilities and transportation corridors remain open.

Fifty-nine carcasses have been discovered so far near the park’s Sweetgrass, Lake One, Trident Creek/Trident Meadows, Peace Point west junction and Flat grass areas. There are three lab-confirmed cases of anthrax as well as three field-tested cases.

Wood Buffalo has had five significant anthrax outbreaks since 1967, including the most recent one in 2015. In past outbreaks, anthrax has had minimal impact because the park has a large number of bison compared to the number that gets anthrax in a typical year. The park has about 3,000 wood bison — the largest free-roaming, self-regulated wood bison herd in the world.

Anthrax is a disease caused by bacteria called Bacillus anthracis. Bison, cattle, horses and other hoofed mammals are especially sensitive to anthrax. The bacteria that causes anthrax occurs naturally in soil, but its presence varies with soil types and climate conditions. It lies dormant in the ground, especially on low-lying or flood-prone land.

After wet weather, hot and dry conditions bring bacteria closer to the surface. Wallowing or pawing at the ground stirs up anthrax-causing bacteria spores, and animals like bison breathe the spores in and get infected.

“We see outbreaks during the height of summer when conditions are hot and dry,” says Parks Canada. “This summer's weather has been the perfect environment for anthrax-causing bacteria to thrive. This is especially so during the past two wet summers.”

Cool, rainy weather slows anthrax outbreaks.

Wood Buffalo National Park is home to around 3,000 wood bison/Darren Roberts, NWT Tourism

Mortality alerts came in from collars on a few bison in the park in mid-July. Then on a routine anthrax surveillance flight, Parks Canada staff saw several dead bison and suspected anthrax. They conducted field tests on July 15 and sent samples from two of the carcasses to the lab.

Staff are doing daily surveillance flights to detect deceased bison. A national incident management team was sent to Fort Smith, Northwest Territories on July 24 to help dispose of carcasses at Sweetgrass Station.

In remote areas, animals are left to decompose since there is little or no likelihood of people coming into contact with the disease.

Animals found near visitor facilities or high-use areas need to be disposed of for public safety. Measures include burning or moving the carcass and treatment of soil to reduce the presence of anthrax spores in the soil.

If you see a carcass, do not approach it but record your exact location if possible and call the Wood Buffalo National Park Duty Officer at 1-867-872-0404.

It is extremely rare for humans to contract anthrax except from direct contact with dead, diseased bison. Anthrax can cause skin, respiratory or intestinal infection in humans. Though infections are serious and could be fatal, antibiotic treatment controls the disease if you act fast.