How to Identify Mixed Breed Cats

The official topic of that issue of the Morbidity and Mortality Weekly Report was emergency room utilization during the Los Angeles wildfires. But stuffed inside the data appendix were H5N1 cat infection investigation records from two Michigan families. A few hours later, the tables were taken down. The CDC's explanation was "inadvertent release."

This happened on the fifteenth day after the Trump administration issued a communications pause to federal health agencies. MMWR had been suspended for two weeks and just resumed. This was the first issue back. Reporters from The New York Times and The Washington Post saved copies before the files vanished.

What was in the leaked data tables?

The first household had two adults, two children, three indoor cats. One adult worked at a dairy farm. Cat 1 got sick first. It stopped eating, lost its sense of direction, went glassy-eyed, then seized. It was euthanized on the fourth day. Brain tissue and nasal swabs came back positive for H5N1, clade 2.3.4.4b, genotype B3.13, a perfect match for what was circulating in Michigan dairy herds. Cat 2 developed respiratory symptoms four days after Cat 1 fell ill, was sick for 11 days, then recovered on its own. The owner refused to have it sampled. Cat 3 was fine the whole time.

Then there was the teenager. Six days after Cat 1 fell ill, one of the children in the household developed flu-like symptoms. Six days after that, the child was tested for H5N1. Negative.

The second household was simpler and more uncomfortable. One dairy worker, two indoor cats. The worker's daily job was collecting raw milk from the farm. He was frequently splashed with milk. He didn't change clothes before coming inside. His six-month-old Maine Coon had a habit of rolling around on his work clothes.

The cat died within a day of falling ill. H5N1, B3.13 genotype.

And this worker, two days before the cat fell ill, had already developed vomiting and diarrhea.

Weese spent a long section of his blog post discussing what that two-day gap might mean. Influenza can cause gastrointestinal symptoms, but that's not the typical presentation. You can't draw conclusions from it. The real question: did this person actually have H5N1? If yes, did he transmit the virus to the cat, or did he just track contamination in on his shoes and clothes? These two possibilities mean entirely different things for public health.

Twenty-four people at veterinary clinics who had contact with these two sick cats were placed on 10-day symptom monitoring and given Tamiflu prophylaxis. Everyone else tested in the first household came back negative. But the two dairy workers, the most likely virus sources, left no samples. Under current U.S. law, nobody can force them to do anything.

Weese wrote: ideally, serological antibody testing should be done on all people and all cats in both households. Even if the acute phase was missed, antibodies can tell you retrospectively who was infected. If the worker tested seropositive, it wouldn't prove he directly infected the cat (could have been clothing contamination), but it would at least confirm he'd been infected. "Either way," he wrote, "that's not good news."

These tests were never done. Two weeks later, on February 20, the full academic version of the leaked report was published as an official MMWR paper. What review it went through during those two weeks, the outside world doesn't know.

Jennifer Nuzzo, director of the Pandemic Center at Brown University, told The New York Times: "If new evidence about H5N1 is being suppressed for political reasons, that is a complete betrayal of the government's duty to protect the American public." NPR's February 13 report quoted an anonymous senior CDC official: "Right now, the administration is controlling which topics can be covered and which cannot." The Washington Post confirmed that three additional avian flu studies had been shelved.

The Michigan events happened in May 2024. The report wasn't published until February 2025, with an "inadvertent release" in between. But during that time, cats kept dying.

Numbers first. The USDA's APHIS database recorded 97 domestic cats confirmed with H5N1 in the United States since 2023. Thirty-six of those were in just the first four months of 2025. California had the most at 20 cases. Oregon 14. Colorado and South Dakota 9 each. By the second half of 2025, the cumulative confirmed count reported by the AVMA had passed 130.

Kristen Coleman at the University of Maryland School of Public Health led her team through a big project. They went through every piece of published academic literature on feline avian influenza infection from 2004 to 2024. Forty-one papers. Twelve felid species, from domestic cats to tigers. Eighteen countries. 607 infections. 302 deaths. Among 423 PCR-confirmed cases, the fatality rate was 71.3%.

Her paper came out in May 2025 in Open Forum Infectious Diseases. The language in the conclusion was, by academic publishing standards, blunt: "We estimate this phenomenon is severely underreported in the scientific literature."

97. 130. These numbers have already lost their meaning. Weese, discussing the Oregon cat food incident, said something plain: "Not a lot of people are going to spend $100 to $200 to test their dead cat." Oregon state veterinarian Scholz held the same view: "Not every owner will do that. I expect as we look back or look forward, there will be more cases."

The question isn't how many cats died. The question is how many cats died and we have no idea.

December 2024. Oregon.

A woman named Acfalle lost her cat Villain. Villain was four, raised from a kitten. Acfalle had been feeding it Northwest Naturals freeze-dried turkey formula raw cat food. The brand was well regarded in the "natural feeding" community. She'd even recommended it to clients.

That morning Villain could barely open its eyes. By the time it reached the emergency animal hospital, the brain had already started to swell. The cat died in Acfalle's arms.

Acfalle did something most pet owners wouldn't. She sent Villain's body to Oregon State University for necropsy. She told CNN she hoped the result would be some blood pathogen. Something she had no control over. The result was H5N1. Genetic sequencing confirmed the virus came from the cat food she'd been feeding. The strain in the food was an exact match to the one in the cat.

Villain's death directly led to Northwest Naturals recalling that batch of 900-gram freeze-dried turkey cat food. The product had been distributed to 12 U.S. states and British Columbia, Canada. State veterinarian Scholz confirmed: "This cat was strictly an indoor cat and did not contract the virus through environmental exposure."

Same month. Los Angeles. Another household. Four cats drank Raw Farm brand raw milk that was later recalled. All four infected, all four dead. Another household: one cat tested positive for H5N1 after eating Monarch Raw Pet Food products. Four other cats in the same family were presumptive positives. The Los Angeles County health department tested Monarch's products. Found live H5N1 virus.

The Los Angeles County health department had already found live virus in the product. One cat that ate the product had confirmed H5N1. Four cats in the same household were presumptive positives. Monarch's response: no credible evidence. CNN reported that Monarch products were sold at multiple farmers' markets across California, including Laguna Niguel, Orange, San Jacinto, and Fountain Valley. Until the FDA stepped in to investigate, the products still hadn't been recalled.

Raw Farm's attitude was about the same. Their statement: "Our products have no food safety issues related to H5N1. This is more of a political issue."

February 2025. A third raw cat food company. Wild Coast Raw, Washington State, chicken formula. Two cats from different households, both indoor, both ate the product, both euthanized due to severity of illness. This time the investigators did something critical: they tested not only the opened containers the cats had contact with, but also unopened products from the same batch. All positive.

The raw meat pet food market has been growing fast in recent years. Consulting firm OC&C called it a "fast-growing" category. A group of pet owners who sincerely believe raw is healthier. A "natural feeding" community. A regulatory framework where virtually nobody had considered avian flu risk before.

As for Acfalle. CNN's reporter asked whether her views on raw feeding had changed. She didn't answer directly. But the report included one detail: after Villain died, she started consulting veterinarians about cooked food feeding plans.

Around Thanksgiving 2024. Shelton, Washington State. Wild Felid Advocacy Center. A sanctuary for large cats, housing 37 big cats: cougars, bobcats, lynxes, servals, caracals, and one Amur-Bengal hybrid tiger.

Cats started going wrong during Thanksgiving week. December 2 the sanctuary posted on Facebook about "unexplained illness in some cats" and suspended public access. H5N1 confirmed December 6. By the time the final update went up on December 20, 20 cats were dead.

Founder Mark Mathews is a veteran. When Seattle Times reporter Lynda Mapes went to interview him, he said the only comparable experience he could find, as a veteran, was being in a war zone.

They destroyed all the meat in the freezers. Washington State's Department of Fish and Wildlife was reporting rising avian flu cases in the state. Same period, two wild cougars in Clallam County were confirmed with H5N1.

Some background from the Seattle Times report: H5N1 had been circulating in Washington State since 2022, starting in backyard poultry, then wild birds. In 2023 the state reported its first seal death from avian flu. In 2024, more than half a tern colony near Port Jefferson was killed by avian flu.

The sanctuary went into quarantine. No new animals, no visitors. Mathews told NBC he was trying to reopen before New Year's. His team was still cleaning out the freezers, disinfecting the facilities, working through quarantine requirements with federal and state animal and public health officials.

Of 37 cats, 17 left. He said this number to multiple outlets. Nothing else.

STAT News ran a piece on March 4, 2025. The byline listed veterinarians, influenza scientists, and biosecurity experts. One core argument: infectious disease surveillance for companion animals in the United States basically doesn't exist.

Here's the situation. Some states have tacked H5N1 onto routine rabies testing. Meaning: only when a cat shows neurological symptoms and rabies is suspected first does avian flu get checked "incidentally." The AVMA now recommends testing all cats with neurological symptoms for both viruses simultaneously. This is not mandatory. No active screening program. No sentinel surveillance network. No systematic epidemiological data collection.

In the spring of 2024, it was the mass die-off of farm cats at multiple Texas dairy operations that tipped veterinarians off to test the cattle. That's how they found out H5N1 had entered the American dairy herd. Cats served as the sentinel. A year later, no surveillance system has been built for this "sentinel species."

Coleman has brought up the 2016 H7N2 incident in New York City in multiple interviews. That time a different avian-lineage influenza got into the animal shelter system. Over 400 cats infected, one veterinarian caught it from a cat. She worries about H5N1 replaying that scenario with worse consequences. Shelters are high-density, poorly ventilated. Staff handle dozens of animals a day.

July 7, 2025. The CDC folded avian flu updates into its routine flu data releases. USDA animal infection data no longer appeared on the CDC website. You had to go to the USDA's own site. Some observers read this as a reduction in the visibility of avian flu information. Second half of 2025, new cases surfaced in Los Angeles of cats dying from H5N1 through commercial raw chicken cat food, B3.13 genotype.

A team at Cornell University's College of Veterinary Medicine published a finding in 2025: they isolated live H5N1 from the urine of an infected cat that had drunk contaminated raw milk. Cat urine. This means cleaning the litter box, something that happens every day, becomes an exposure scenario when the cat is infected.

The CDC wrote one line at the end of that MMWR paper, the one finally published after a two-week delay: "Although reported cases of HPAI A(H5N1) infection in indoor cats are rare, such cats may pose a risk for human infection."

There are 950 million domestic cats in the world.