Polish Cats
Keep an eye on what’s happening with Polish house cats.
There has been an outbreak of H5N1 flu, the type that has been decimating birds, in at least 16 house cats in Poland. They all died. More cats are being tested. More than 80 are suspected of being infected.
Bird flu seldom crosses over into such mammalian species. When it does, it’s usually worse than flu crossing over from pigs.
Crossing the species barrier tends to make a pathogen more potent (for example, as happened with Mexican Urban Dog rabies). The 1918 Spanish flu is believed to have originated in birds. Polish Veterinary Institute says the strain in the cats is very similar to a strain found about a month ago in a white stork in the Tarnów region, so it started out in the pandemic affecting birds.
Of the viruses that often afflict humans, flu is among the ones that mutate rapidly. Officials in Poland say the virus in the cats is so similar, it probably came from a "single, unidentified source." (Food is suspected.) If it came from multiple different sources, the virus would vary more among the cats. The infected cats don’t all live very close to each other, although they are within a limited radius. Some of them are indoor house cats that have no possible exposure to wild birds and can’t roam to visit with each other.
Officials add, "In addition, molecular analysis indicates the presence of mutations that enhance the virus' adaptation to mammals."
Is the hair on the back of your neck standing on end now? This is how the Spanish flu pandemic got started in humans. It is apparently how SARS-CoV-2 got started in humans too. Bird flu has to pass through an intermediate species to learn how to infect us efficiently. For months, it has been so close to making the jump that a mutation in just one or two key locations could do the trick.
When bird flu does get into humans, it tends to be much more deadly than typical influenza. USA’s NIH says the Spanish flu had an estimated case fatality rate (CFR) of more than 2.6%. The usual rate is under 0.1%. NIH estimates the CFR for COVID at about 1% in the general population.
So keep an eye open for news about Polish cats and think about what you’d like to have at home if this gets out of hand. It’s summer now, which is low season for flu. I look at it like getting ready for hurricane season on the Texas coast. I’d get ready ahead of prime time and then hope the preparations won’t be needed.
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Postscript: If you want to know what I’m especially watching about COVID, it’s the surge in Japan, especially Okinawa where the case load has approximately quadrupled in a month. I don’t understand enough about what is going on there to post about it yet, but it looks like it deserves more attention than it is getting.
Addendum: A woman who owned one of the afflicted cats provided samples of the raw chicken breast meat she bought at a major supermarket and fed to her cat. It tested positive for H5N1 flu and the virus was able to be cultured from the sample. Food is now the prime suspect as the central source of the outbreak.