6 domestic cats have tested positive for bird flu in Colorado so far this year

DENVER — For months, avian influenza — better known as bird flu — has been detected in cattle and chickens across Colorado but it has now spread to at least six domestic cats, according to the Colorado Department of Public Health and Environment (CDPHE).

One of those infected cats was "directly associated with a known infected commercial dairy facility," two other cases were "indoor only cats with no direct exposure to the virus," and the three remaining were known "indoor/outdoor cats that hunted mice and small birds, but also spent time inside with their owners," the CDPHE said.

At least three of the cats infected with bird flu were in Larimer County, according to the U.S. Department of Agriculture's Animal and Plant Health Inspection Service. A fourth cat case was found in Adams County and a fifth in Morgan County.

Denver7 has followed how the bird flu has developed around Colorado in recent months:

• On July 3 , state officials announced that a Colorado dairy worker was diagnosed with bird flu. This marked the fourth case tied to an unprecedented outbreak of highly pathogenic avian influenza among dairy cattle in the U.S. Colorado health officials believe this was the first instance in which avian influenza was likely transmitted from a mammal to a human.
• In early July, Colorado Gov. Jared Polis declared a disaster emergency following the latest avian flu outbreak at a commercial egg facility in Weld County.
• In mid-July , state health officials confirmed to Denver7 that three poultry workers at a commercial egg-laying facility in Weld County affected by an outbreak of highly pathogenic avian influenza have tested presumptive positive for bird flu.
• On July 14 , health officials confirmed four poultry workers in Colorado had been diagnosed with bird flu.
• On July 23 , Colorado announced it would be the first state to mandate testing for H5N1 at dairy farms. Denver7 has a deep dive into what this means here . We looked into the impact on egg prices here .
• Three Colorado poultry workers at a second egg facility tested positive for the bird flu, state officials said on July 25 , bringing the total number of confirmed human cases in Colorado to 10 for the year.

Dr. May Chu, epidemiologist at Colorado's School of Public Health, said the infected cats that spent time both outside and inside could have been infected by other animals.

"It's very likely that the cats who wander off or wander out may have caught a deer mouse or some kind of forage that they go through and they pick up something from an infected rodent," Dr. Chu said.

Dr. Gina Rodriguez, medical director at Evans East Animal Hospital, said symptoms look like a common cold.

"It can be as vague as lethargy, which is just kind of feeling under the weather," she said. "So, sneezing, eye discharge, nose discharge, coughing."

The six domestic cats were only diagnosed after they were tested for rabies first, explained Dr. Rachel Herlihy, state epidemiologist with the CDPHE.

"We know that rabies causes neurologic symptoms, and so that can include things like lack of coordination, inability to stand, tremors, or even seizures might occur in cats and so those are the same types of neurologic symptoms that can be seen in this H5N1 influenza infection," she said.

Dr. Rodriguez said she hasn't seen or heard of any cases in the Denver area, and both Dr. Herlihy and Dr. Chu told Denver7 these infections aren't something cat owners should panic about at the moment.

The cases are rare right now, Dr. Herlihy said, but added that cat owners should stay vigilant, especially for those who work or live near dairy farms.

There has been no transmission from infected cats to humans, she said.

"When we talk about risk to pets, we know that pets have very close contact with humans, so it's important to know that no human cases of this virus have been linked to exposure to infected cats, so we haven't seen cat-to-human transmission, so that's really important to know," she said. "But we do want people who may have contact with a cat that is suspected to have this infection to take the same precautions we are asking workers on farms to take, and so that's going to include things like PPE wearing masks, gloves, eye protection."

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