DENVER — For months, bird flu — better known as avian influenza — has been detected in cattle and chickens across Colorado, but now it has 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 “exclusively indoor cats with no direct contact with the virus,” and the remaining three were known “indoor/outdoor cats that hunted mice and small birds but also spent time indoors with their owners,” according to the CDPHE.

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

Denver7 has been following the development of bird flu around Colorado over the past few months:

• On July 3State authorities announced that a Colorado dairy worker had been diagnosed with bird flu. This was the fourth case linked to an unprecedented outbreak of highly pathogenic bird flu among dairy cows in the United States. Colorado health officials believe this was likely the first case of bird flu being transmitted from a mammal to a human.
• Beginning of July Colorado Governor Jared Polis declared a state of emergency following the recent outbreak of bird flu at a commercial egg plant in Weld County.
• Mid-JulyState 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 avian influenza.
• On July 14Health officials confirmed that four poultry workers in Colorado had been diagnosed with bird flu.
• On 23 JulyColorado announced that it would be the first state to require testing for H5N1 on dairy farms. Denver7 explains in detail what this meansWe looked at the impact on egg prices here.
• Three poultry workers at a second egg factory in Colorado tested positive for bird flu. State officials said on July 25bringing the total number of confirmed human cases in Colorado this year to 10.

Dr. May Chu, an epidemiologist at the Colorado School of Public Health, said the infected cats, who spent time both outdoors and indoors, may have been infected from other animals.

“It’s very likely that the cats that are running away or wandering have caught a deer mouse or some kind of food that they are digging through and in doing so they picked up something from an infected rodent,” Dr. Chu said.

Dr. Gina Rodriguez, medical director of Evans East Animal Hospital, said the symptoms were similar to a cold.

“It can be as vague as lethargy, a feeling of not being well,” she said. “So sneezing, eye discharge, nasal discharge, coughing.”

The six domestic cats were only diagnosed after they had been tested for rabies, said Dr. Rachel Herlihy, state epidemiologist at CDPHE.

“We know that rabies causes neurological symptoms. These can include things like incoordination, inability to stand up, tremors, or even seizures in cats. These are the same types of neurological symptoms that can occur with H5N1 influenza infection,” she said.

Dr. Rodriguez said she has not seen or heard of any cases in the Denver area, and both Dr. Herlihy and Dr. Chu told Denver7 that these infections are not a cause for panic for cat owners at this time.

Cases are currently rare, Dr Herlihy said, but added that cat owners should remain vigilant, especially if they work or live near dairy farms.

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

“When we talk about the risk to pets, we know that pets have very close contact with people, so it’s important to know that no cases of this virus in humans have been linked to contact with infected cats. So we haven’t seen any transmission from cats to humans. So that’s really important to know,” she said. “But we want people who may have contact with a cat suspected of having this infection to take the same precautions that we ask workers on farms to take. That includes things like wearing PPE masks, gloves and eye protection.”