By Kathryn Reed

Not every bear has always been able to be released into the wild, but until this year none had mysteriously died at Lake Tahoe Wildlife Care.

Two have in a three-week period.

The diagnosis is adenovirus.

“It is rare,” Peter Tria with the California Department of Fish and Wildlife said of the disease. “It has never been detected in free range wild black bears ever to our knowledge. It has been detected in captive bears.”

While the South Shore rehab facility’s goal is to heal injured animals and return them to their natural environment, the animals are considered captive while being treated.

This the first time anything like this has happened in the 17 years LTWC has been treating black bears under a permit from the state. (The facility has been open since 1978.)

The disconcerting thing is that it’s not known how the virus got into the facility. It is a strain found in canines and coyotes. However, it is something domestic dogs can be vaccinated against so those cases are seldom seen. Humans can also get the virus.

“We might not ever know (how we got it), but we are trying to prevent it from happening next year,” LTWC owner Tom Millham told Lake Tahoe News.

The four remaining bears have tested positive for adenovirus. However, they are continuing to put on weight, as is normal as they bulk up for their winter slumber. (Two of the original eight bears being cared for this season have already been released.) The bear deaths occurred in August and September.

Millham is now the only one allowed into the bear cage. Instead of feeding the bears twice a day, they are getting a larger quantity once a day. He’s wearing a disposable hospital gown, gloves and dipping his shoes in a bleach solution before putting on booties.

The goal is to keep that pen from being exposed to any outside contaminant. The bears are essentially quarantined.

Tria told Lake Tahoe News the state is happy with the measures LTWC is taking to ensure all of the animals’ health.

UC Davis and Cornell University have received blood samples. Scientists there, along with the state officials and local veterinarian Kevin Willits are trying to get to the bottom of the virus, but it’s possible answers may always be elusive.

Cheryl Millham, the other owner of LTWC with her husband, speculates that if their facility on Al Tahoe Boulevard that is being built were complete, it would have been easier to separate the sick animals. But until more funding is secured, the site continues to operate in the Millhams’ back yard.