'Just didn't seem quite right': Bears with rare disease appear unfazed by humans, worrying officials

A brown bear cub became an internet star in 2019 for approaching a snowboarder in Northern California. While the interaction may sound cute, some instances of bears mingling with humans have caused concern among state officials. 

A small black bear showed up in a residential backyard this February in Pollock Pines, a city in California's Sierra Nevada mountain range, and appeared to be unfazed by humans. Residents gave food and water to the bear, which then received pets after jumping into an open car trunk, according to the California Department of Fish and Wildlife. State officials who arrived on the scene determined that the bear "just didn’t seem quite right."

The bear was taken to a state wildlife lab where it was found covered in ticks, malnourished and displayed neurological abnormalities. A week later the bear was euthanized, and autopsy results showed the bear had encephalitis, an inflamed brain. 

Peter Tira, a state fish and wildlife public information officer, told USA TODAY the first case of a bear with encephalitis was brought to the state’s attention in 2014. Since then, there have been about a dozen confirmed cases. 

“We're encountering them more frequently, which is troubling,” Tira said. 

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What symptoms appear in bears with encephalitis?

Aside from the friendliness with humans, symptoms of bears with encephalitis include head tilting, muscle tremors and circling to one side, Jamie Sherman, a veterinarian at University of California, Davis' One Health Institute who has studied bear diseases, told USA TODAY.

But she added that diagnosing a bear with encephalitis can be done only after the bear is dead. There is no answer for what is causing the disease, which leads to questions  about how long the disease has been around in the species.

“Looking at those neurologic symptoms, which goes beyond them potentially not running away from a human, it's more than that,” Sherman said. “You have to ask the question to yourself: 'Is this something that we're just noticing now? Or is it truly something that's new?'” 

Scientists said they have discovered five novel viruses, previously unknown, in the bears but do not know whether it causes the inflammation. 

“We don’t know what, if any, health risks these bears might pose to other animals,” California veterinarian Brandon Munk said. 

The word "virus" may be taboo nowadays, but Sherman said there is no evidence of humans being at risk of anything related to the bears. Still, she said, humans should always keep their distance from bears.

As much as it is a unique experience to get up close to a wild bear, Sherman said, the average bear would run away from a human, but interactions are bound to happen as each population rises. California’s department of fish and wildlife estimated the black bear population more than doubled from 1982 to 2016. 

Concerns over mistaking curious bears with possibly sick animals

Ann Bryant, executive director of Bear League, a nonprofit that is “committed to keeping bears safe and wild in their natural habitat,” said people should not assume that a bear that isn’t scared of humans is sick, noting that most of the sick bears are young.

“They're just leaving their mother. They’re alone for the first time out in the world. They will sometimes approach people because they're hungry, and they don't know what's going on yet," Bryant said. "They don't have their act together, kind of like teenage kids. This is normal, and they outgrow it, and they get better.”

She added that  such encephalitis cases are rare, and she worries that people learning about it will cause unnecessary fear. 

“I’m afraid that it's going to just make people and wildlife agencies completely overreact and they're going to start killing innocent, normal, healthy dispersing young bears,” Bryant said. “People don't need to panic at all. The state wildlife agencies out here in the West, they've got a handle on it.”

If people are unsure whether a bear is healthy, Bryant said, they can take video footage of the animal and send it to her organization. That way no innocent animals are hurt.

Though encephalitis is a near-fatal disease, not all hope is lost. The cub that became famous from the interaction with the snowboarder is still alive. Benji, now 3 years old, lives at the San Diego Humane Society’s Ramona Wildlife Center, where officials say he must remain because of a neurological condition and his history of approaching people. 

Follow Jordan Mendoza on Twitter: @jord_mendoza.