Montana Grizzly Bears Acting Strangely from Highly Pathogenic Virus Killed

A highly contagious strain of bird flu has been detected in three grizzly bears in Montana, the first time the disease has been found in grizzlies.

The three bears tested positive for highly pathogenic avian influenza (HPAI) in fall 2022, and were found to be suffering from neurological issues, including disorientation and partial blindness, Montana Fish, Wildlife and Parks (FWP) said in a January 17 statement.

The young bears, found in three different areas, were later euthanized due to the severity of their symptoms.

Avian influenza, also known as bird flu, is a viral disease spread via direct contact with infected feces and respiratory secretions.

As its name suggests, HPAI and other forms of avian influenza viruses usually infect birds. Centers for Disease Control and Prevention (CDC) data shows that as of January 11, over 57 million poultry across the U.S. were infected by HPAI, most of which have died or been culled, while nearly 6,000 wild birds had tested positive as of January 12. This outbreak is one of the largest in history, and is partly responsible for soaring egg prices.

Birds kept in close contact with one another, as they are in poultry farms, are much more prone to spread the infection between individuals.

Avian influenza comes in both "low pathogenic" and "highly pathogenic" forms. While low pathogenic strains cause only minor symptoms in birds, highly pathogenic strains are very infectious and can be much more deadly. According to the United Nations Food and Agriculture Organization, HPAI has become common in several countries, including Bangladesh, Vietnam, China, Egypt, India, and Indonesia.

If spread from birds to mammals, the disease can cause exhaustion and neurological problems like seizures.

The three infected grizzlies found in Montana are the first documented cases of HPAI in grizzly bears. The virus has been detected in other bear species before, with the first bear in the U.S. to test positive for HPAI being a black bear cub in Alaska. The cub was neurologically damaged, and was also euthanized.

"It was very sad to see the animal (was) not going to recover," Kimberlee Beckmen, a wildlife veterinarian for Alaska's Department of Fish and Game, told Alaska Public Media in November 2022. "Its brain was swollen, and it would have died, probably within hours, had it not been euthanized."

Last year, a fox and a skunk in Montana also tested positive for the disease, with other infected species across other states and countries including raccoons, rodents, ferrets, pigs, cats, dogs, horses, and even coyotes and tigers.

Montana FWP Wildlife Veterinarian Jennifer Ramsey said in the statement that she suspects that these mammals were likely infected after consuming infected birds.

Avian flu can be spread to humans occasionally, though sporadically. Those most at risk include people who work in close and repeated contact with infected birds or heavily contaminated environments, according to the World Organization for Animal Health.

Symptoms of the disease in humans include fever, coughing, nausea, abdominal pain, vomiting, diarrhea, eye infections and difficulty breathing, among others. As of April 28 last year, only one person in the U.S. had a recorded case of HPAI, CDC data shows.

The Montana FWP urged Montana locals to take precautions when handling game birds, sick or dead birds and mammals they find, and to avoid contact with sick or dead wildlife if at all possible.

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