UPDATE: H5N1 Avian Influenza and Cats
Back in April, I wrote about a new strain of High Pathogenic Avian Influenza (HPAI) isolated in a few species, including cats. As discussed in that post, unsafe foods like raw milk and raw meat were suspected as a possible transmission source.
Over the last 8 months, more cases have been identified which provides a bit more information on how to avoid and diagnose H5N1 in cats. As of writing this post, the CDC has 65 confirmed human cases in the United States, mostly in California and Washington.
Unfortunately, cats seem to be especially susceptible to severe illness from H5N1, with most known affected cats dying. The AVMA recently posted about H5N1 in cats with some general information and updates.
How Are Cats Infected?
Most often, cats are exposed via unpasteurized milk and raw or undercooked meat. Exposure to infected wild birds or poultry is also a possible source.
One known exposure from raw food was proved when the food also tested positive for H5N1.
Raw milk was identified as a source in California.
Like any influenza, direct exposure to infected respiratory tissue and discharge is a source of infection. Cats could get sick by exposure to infected cows, as well as birds including poultry (chickens, turkey) and wild birds.
What Clinical Signs Have Been Identified?
Many cats initially have loss of appetite, lethargy, and fever, but quickly progress to:
-Neurologic signs including ataxia, tremors, circling, seizures, or blindness
-Severe depression or lethargy
-Oculonasal discharge, often severe
-Respiratory signs including sneezing, coughing, increased respiratory rate and effort, and difficulty breathing
Is Testing Available?
Yes, but it's a bit complicated.
PCR testing is the standard, however false negatives are not uncommon, and results can take days to a week.
The most appropriate use of PCR testing would be for surveillance. Clinical testing (ie using the test to diagnose a single sick animal) is less relevant since it would not impact patient care. It could help inform the household or vet hospital treating the cat, but false negative tests can mean there is still risk, so "what we do" doesn't change much regardless of the test results.
There are rapid in-clinic H5N1 tests, but they have not been well evaluated on animals, and false positives are very common.
Can Humans Get Sick?
Yes, though it is currently rare overall.
Using appropriate PPE (Personal Protective Equipment) such as a mask (N95 respirator or equivalent), gown, gloves, and eye/face protection may be a safe choice when handling infected cats.
What Should You Do If You Suspect Your Cat May Have H5N1?
Currently, it's extremely rare for cats to have H5N1. However, if you are concerned:
-Contact your veterinarian before going in as long as your cat is stable. Describe the clinical signs so they can be prepared when you arrive
-Limit contact with the cat and any immunocompromised people or pets
-Follow CDC recommendations for Ways to Stay Health Around Animals
-Monitor any people or pets that may have been exposed for clinical signs of illness
How Can I Prevent My Cat From Infection With H5N1?
-Do not feed raw milk or meat. All meat should be thoroughly cooked
-Keep cats indoors to avoid exposures to birds
-Avoid contact with sick or dead birds
-Keep cats away from livestock, poultry, and their environments, especially in areas/states with known H5N1 outbreaks
-Thoroughly wash your hands before and after handling your cat
-Wash your hands and any exposed skin, as well as change your clothes and shoes if you have interacted with sick or dead animals that may be harboring H5N1
Original Blog from April 15th 2024 What is Influenza?
Influenza viruses have always been a challenge to manage because they typically infect multiple species. Birds can become infected by all Influenza A subtypes except two, which have been found only in bats. Only some subtypes are transmissible to humans. Any time a new strain of influenza is found in an unexpected species, there is concern for more widespread disease. Many organizations (CDC, USDA, WHO, etc) monitor influenza closely. Animals act as “mixing vessels” which can create new and more problematic flu viruses. For example, H3N2 started off as an avian only flu strain, but has host-adapted to dogs, and is now endemic in some parts of Asia and the US.
The most concerning influenza strains are “High Path Avian Influenza” (HPAI), which typically spread rapidly and have a high death rate in birds. All HPAI are types H5 or H7, but not all H5 and H7 subtypes are HPAI. Wild birds are often a source, as they travel long distances and easily transmit via virus in bird droppings. The virus can persist for weeks in damp, cool environments like manure.
What is happening now?
Here is the CDC’s H5N1 Bird Flu: Current Situation Summary
At the end of March, the USDA, FDA, and CDC issued an update that confirmed HPAI (H5N1) in dairy herds in Texas, Kansas, and Michigan, with presumed positive test results in Mexico and Idaho. This strain appears to have been introduced from wild birds to the cows. Previous to March H5N1 has only been found in birds, humans, cats, and goats, but this is the first documented case of H5N1 infections in cattle.
Consumable products from infected cows are not a concern for transmission if meat is fully cooked and milk is pasteurized. Raw milk and meat are never safe to consume, both for humans and for pets.
What is currently concerning is there are now preliminary reports of H5N1 transmission to humans and cats. A few humans have had mild disease, mostly conjunctivitis, and some cats have been found with severe disease or dead.
While the media is reporting “100% fatality” for infected cats, this is likely way overblown, as there is huge sampling bias. Only already dead or severely sick cats are being tested, so many mildly affected (or asymptomatic) cats are not “counted.”
What does this mean for you?
If you own a cat, consider limiting exposure to birds. This has been true for years now that HPAI is so widespread, but may be especially important with a new strain we don’t fully understand yet. Keep cats indoors, and limit bird/cat contact by discouraging birds near your home (remove bird feeders, etc). Data is limited, but there have been reports of raw meat transmitting H5N1 to cats, so as always, do not feed raw meat to your pets. Your cat’s lifestyle will help dictate how concerned to be if they come down with symptoms of a cold. If this is an indoor-only cat, this would be less concerning than a kitty who spends a lot of time outside and is a known bird hunter.
What about dogs?
We know dogs can typically get H5N1 stains, so keeping dogs away from birds is probably a good idea. This is especially true for dead birds, which may be tempting for dogs to investigate.
Written by Dr. Zachary Glantz
Medical Coordinator/Veterinarian at Art City Vets
Comments