Any occurrence of anthrax is of serious concern, as it can spread to humans.

There have been outbreaks before, in Alberta, the Northwest Territories, Saskatchewan, Manitoba and Ontario. Thirty head of cattle died of the disease near Rocky Mountain House Alberta in 1999. This resulted in a massive vaccination of 15,000 animals.

The anthrax-bearing spores that infected the cattle came from the remains of bison in the soil. The spores can remain viable for hundreds of years, and are more likely to become air-borne during periods of dry weather.

The first documented outbreak of anthrax among bison occurred in the summer of 1962, when 281 bison died near Hook Lake, in the eastern Slave River Lowlands in the Northwest Territories. Besides bison and cattle, anthrax can infect moose and other animals in the wild.

There's a double-whammy to these anthrax outbreaks: the spores can be roused into the air by animals digging and rolling in the soil, and they can also be spread by the dead carcasses of anthrax-infected animals opened by scavengers. Ravens are a major scavenger of these dead carcasses, but ravens somehow are immune to anthrax, though they can transport the deadly spores over great distances.

Spread to humans

The anthrax virus is quick and deadly, and can spread to humans, though a prompt and effective vaccination program usually prevents this. Anthrax is one of the agents in the arsenal of biological warfare. The U.S. Department of Defense has introduced a program of systematic vaccination of military personnel.

Humans can be infected by handling animal products from infected animals and by inhaling anthrax spores, as the wood bison probably did this summer in a small and isolated herd in Wood Buffalo National Park. Anthrax can also spread if humans eat undercooked meat from infected animals.

The initial symptoms of anthrax infection are much like that of a common cold. In days this can progress to severe breathing problems and shock. Inhaling anthrax spores can lead to death in a day or two. Anthrax infection can be treated effectively with antibiotics — if the treatment is initiated promptly.

Another concern with anthrax-infected bison is the growing number of bison ranches, especially in Alberta, but also in Saskatchewan and Manitoba— and in parts of the United States. Media baron Ted Turner is the biggest bison rancher in the world, with some 20,000 head of bison in Montana, Nebraska, New Mexico and South Dakota.

Bison in Canada

Bison meat is described as "nutrient-dense," which means it is lean and extremely high in protein. There are fewer calories and less cholesterol in bison meat than in either beef or chicken. Most bison ranches are organic operations, as the animals do not require the vast amounts of medication cattle do.

Except for their prodigious strength — bison can hoist fence posts out of the ground — and their tendency to roam when sprung free, bison are considered easy-keep animals. They are smarter than cattle, their feed costs are lower, they can deliver their own young, and they spread out so as not to overgraze. They also can keep reproducing as long as 25 years, whereas cattle rarely continue to reproduce longer than 12 years.

A well-run bison ranch uses every bit of the animal — their meat is used for burgers, steaks, roast, jerky, tenderloin and salami, and their hides can be made into jackets, purses, moccasins, boots, riding chaps and exquisitely soft gloves. The skulls often are boiled, cleaned, bleached and used as material for aboriginal artists. The coat ("robe") can fetch a huge price and be made into an expensive overcoat.

Bison also can swim, and they hate horses, learned behaviour from the days when they were slaughtered by the million on the plains. Some bison ranchers use motorcycles to round up stray animals. They are also fast afoot. Len Ross, who ranches 150 head of bison near Taber, Alberta, has a sign on one of his fences that says, "Don't try to cross this field unless you can do it in 9.9 seconds. The bull can do it in 10."

Bison often are inaccurately called buffalo. The term "buffalo" properly applies to the cape buffalo and water buffalo of Asia and Africa. North American bison belong to the bovidae family of mammals, as do domestic cattle.

Wood Buffalo National Park was established in 1922 to protect the last remaining herds of wood bison in northern Canada. Today the park protects one of the largest free-roaming, self-regulating bison herds in the world. It is also Canada's largest national park, and one of the largest in the world.

The wood bison were declared extinct in 1940, the result of over-hunting and crossbreeding with other species of bison. Seventeen years later, federal wildlife officers happened to fly over a remote area in Wood Buffalo National Park. From the air, the wildlife officers detected a small, isolated herd of bison, which, on closer inspection, turned out to be the last remaining pure wood bison in the world. Eighteen of these bison were taken to an isolated area north of Great Slave Lake in the Northwest Territories, a place known today as the Mackenzie Bison Sanctuary.