In Poland, more than 20 cats have died from an infection with the H5N1 bird flu virus. This worries owners and the World Health Organization (WHO). It therefore published a formal report on the outbreak of the disease in Geneva on Monday. This should prompt other countries to tighten surveillance. According to the Friedrich Loeffler Institute (FLI), which is responsible for animal health, there is no evidence of H5N1 in pets in Germany.
According to preliminary findings, no one from the environment of the cats in Poland has contracted the virus. The WHO assessed the risk of infection as low in general, and low to moderate for animal owners and animal care workers.
Avian flu has been circulating in wild birds for decades. The number of cases has recently exploded. “There have never been so many cases in wild birds,” said the FLI. The virus variant 2.3.4.4b has been in circulation since 2020 and is increasingly infecting mammals. Experts fear that over time the H5N1 viruses will adapt to mammals to the point where animals – and then possibly humans – will infect each other on a large scale. So far, individual infections in humans are known, but not transmission from person to person.
“Sporadic infections of cats with the A(H5N1) virus have been reported before, but this is the first report of a large number of infected cats in a large geographic area within one country,” the WHO said, referring to Poland.
In Germany, H5N1 viruses were not found in domestic animals, but in wild foxes, among other things, according to the FLI on request. However, there is no evidence that animals have infected each other. “Each case is so far an isolated case, which must have come about as a result of contact with different wild birds.”
Since the virus also circulates in Germany, individual infections in cats, for example through contact with diseased wild birds, cannot be completely ruled out, according to the institute. Dogs, on the other hand, are not particularly susceptible to bird flu viruses.
In Poland, the first reports of a mysterious deadly disease in cats appeared in a veterinary forum in mid-June. Symptoms include stiffness of the limbs, shortness of breath, convulsions and seizures. At the end of June, the main veterinary office announced that the bird flu virus had been discovered in nine of eleven samples from dead cats examined. The infected cats came from distant regions: Danzig (Gdansk) in the north, Poznan (Poznan) in the west and Lublin in the east of the country.
The Polish authorities recommend that concerned cat owners should not let their animals out of the house or bring them into contact with wild birds and wild animals. If the cat has access to the balcony, the floor should be disinfected beforehand. Another recommendation is to keep shoes that have been worn outside the home out of the reach of cats.
In total, the Polish authorities examined 46 samples from cats and one from a desert lynx (caracal) kept at home. The H5N1 virus was detected in 29 samples. It is not yet known how the cats got infected. It is possible that they had contact with infected birds, according to the WHO. However, the virus has also been detected in cats kept in a clean household. There are indications that the virus could have been transmitted via the food, said virologist Krzysztof Pyrc from the Jagiellion University in Kraków in the newspaper “Gazeta Wyborcza”.
“According to the information available from Poland, there is no evidence of cat-to-cat or cat-to-human transmission,” writes the FLI. Nevertheless, the accumulation of cases should be followed closely. According to the FLI, the genetic adaptations of the virus observed in cats to date are comparable to the changes that have been known for a long time and allow improved virus replication in the mammalian host. “Further mutations have not yet been observed in the examined sequences in Poland.”
