Two Michigan dairy workers may have transmitted the avian flu to their pet cats last May. It suggests a new study published Thursday by the Centers for Disease Control and Prevention.
In one household, the infected cat may have given the virus to others in the house, but limited evidence makes it difficult to confirm the possibility.
The results are from a study scheduled to be published in January, but were delayed by a Trump administration suspension over communications from the CDC.
A single data table in the new report appeared briefly online in a paper on California wildfires two weeks ago, and soon disappeared afterwards. That strange incident prompted calls from public health experts for the release of the research.
The new paper leaves key questions unanswered, including how cats were first infected and whether farm workers would spread the virus to cats and other people in their homes, experts say I did.
“I don't think it's certain if this is human-to-cat, or cat-to-human, or cat-to-human,” said Jennifer Nuzzo, director of the Pandemic Center at Brown University School. There was public health.
Michigan officials began investigating two households in May last year that only indoor cats showed respiratory and neurological symptoms, and after their death, they tested positive for the virus called H5N1. Officials interviewed cat owners and household members and offered to test for the virus.
Both cats were dairy workers. The farm was not known to have infected the herd, as the first farm workers did not work directly with the cattle. However, workers reported that many of the cats in the barn on the farm's property had recently died. Workers also reported that cats in their first household experienced vomiting and diarrhea before they became ill.
The second farm worker reported milking its face and eyes and experiencing eye irritation. Both workers refused to test.
“This study provides further evidence that farm workers with high risk exposures may refuse to test,” Dr. Nuzzo said.
“To protect people and get ahead of this virus, we need to remove obstacles for patients to get tested,” she added. “People should not be afraid that positive tests will cause financial distress or other personal harm.”
In the first farm worker's household, the first cat had a sick cat exhibited a decrease in appetite, lack of grooming, abnormal walking and lethargy, which quickly worsened. She was euthanized on the fourth day of her illness.
Two cats in the home reduced watery eye drainage, rapid breathing and appetite four days after the first cat became ill. The cat recovered and was not tested for the virus. The third cat had no symptoms and was tested negative for the virus 11 days after the first cat became ill.
Neither cats nor humans in the household drank unpasteurized milk. It is unclear how the cat was infected, but experts said it is likely that farm workers contracted H5N1 at work and brought the virus home to the cat.
“If you love cats, you'll probably kiss your head if it allows you,” said Kristen K. Coleman, an infectious disease researcher at the University of Maryland.
Adults and 2 adolescents – 3 people in the household tested negative for H5N1. Six days after the first cat became ill, one adolescent was ill with cough, sore throat and body pain, while the other reported cough caused by an allergy.
However, it was not impossible for the young man to get infected with H5N1 picked up from a cat, as the adolescent was tested late 11 days after he became ill.
In late May, a pet cat from a second household developed severe neurological symptoms, including loss of appetite and minimal movement, and died within a day. After death, the cat tested positive for avian flu.
Cat owners transported unpasteurized milk, such as from farms with known avian flu outbreaks. According to the survey, the owners “did not wear personal protective equipment (PPE) while handling raw milk. Frequently reported milk splash exposure to face, eyes and clothing. When returning from work I didn't take off my work clothes before I entered the house.”
Cats who have become ill were known to “roll their owner's work clothes,” the study said.
Dr. Keith Paulsen, director of the Wisconsin Veterinary Diagnostics Institute, said the virus in the raw milk scattered across those clothes could be the source of infection in cats.
“At this point, I think the higher risk is exposure from raw dairy products,” he said. “There are so many viruses in milk.”
Of the 24 veterinarian staff potentially exposed to infected cats, seven reported symptoms such as nasal traffic and headaches. Only five people agreed to the test. Everything was negative.
Dr. Coleman recommended that veterinarians pay attention to the possibility of avian flu infection when they see a sick cat. “Pet owners shouldn't need to resort to post-mortem sampling to get a diagnosis,” she said.
