Michigan health officials have revealed in emails that owners of domestic cats may have spread bird flu to their pets. This is “raising concerns” of new transmission patterns of the virus.

The emails were obtained via record requests and documented the ongoing struggle to track cases of the H5N1 virus in cats. They suggest that domestic cats may become infected from droplets known as fomites on their owners’ persons.

“If we only could have gotten testing on the [REDACTED] household members, their clothing if possible, and their workplaces, we may have been able to prove human-to-cat transmission,” officials wrote in a July 22nd email obtained by KFF Health News, as reported by Newsweek. Another email has urged the publishing of a report “to inform others about the potential for indirect transmission to companion animals.”

These emails are just the latest released in a slew of recent cat-related infections across the United States, most notably in Colorado, where six cats have tested positive for H5N1 in 2024. Two of these cases occurred in indoor-only cats with no direct exposure to infected animals.

The Colorado infections were confirmed by the Colorado Veterinary Medical Association (CVMA) in an update posted on its website in August.

“Indoor Only” Cats Test Positive For Bird Flu

“One of these cases was directly associated with a known infected commercial dairy facility,” the update said according to Newsweek. “Two of the six cases were indoor-only cats with no direct exposures to the virus. Three of the six cases were known indoor/outdoor cats that hunted mice and/or small birds as prey and also spent time indoors with their owners.”

“There have been 53 detections in domestic cats since the onset of the 2022 outbreak,” Will Clement, senior advisor for strategic communications at the USDA, told Newsweek.

“As companion animals, domestic cats provide a potential pathway for avian influenza viruses to spillover into humans,” Kristen Coleman, an assistant professor at the University of Maryland School of Public Health, said in a June statement coinciding with a study she authored on the spread of bird flu in cats.

Other than the aforementioned two cases of cats contracting bird flu, the others were all in cats that had direct contact with outside birds on farms.