Avian influenza virus infects a cat
In late December, a sick cat in the Deux-Sèvres département tested positive for the highly pathogenic avian influenza virus H5N1. ANSES was actively involved in the investigation of this case, which led to a nearby duck farm being identified as the source of the cat's contamination. The increase in such viral transfers from birds to mammals in different countries calls for vigilance, as they could facilitate the possible transfer to humans.
Contamination observed in France for the first time
ANSES, the national reference laboratory, confirmed the contamination of a cat by the highly pathogenic avian influenza virus H5N1 in late 2022. The cat, which lived near a duck farm affected by the virus, suffered severe neurological symptoms due to the viral infection and had to be euthanised.
The susceptibility of cats to highly pathogenic avian influenza (HPAI) viruses has been known since 2004, and had already been demonstrated in Thailand and Germany in 2006. However, this is the first time that such contamination has been observed in France.
A virus that adapts to mammals
The virus detected in this cat had genetic characteristics of adaptation to mammals. As noted previously, the avian influenza virus can occasionally infect mammals due to genomic mutations. However, it is important to verify that these phenomena remain sporadic and that the viruses that have acquired this ability to cross into mammals are not detected on poultry farms.
Genetic investigations carried out by ANSES confirmed that only the cat was a carrier of this mutant virus and that this mutation was not present, at this stage, in the ducks on the farm where contamination occurred.
Vaccinate against seasonal flu to avoid the emergence of a new virus
Contamination of pets such as cats could make it easier for the virus to cross into humans. It is therefore essential to keep them away from contaminated farms and from operations to cull infected ducks.
In addition, professionals exposed to swine and avian influenza viruses are advised to get themselves vaccinated against seasonal flu. This is because simultaneous infection with an avian influenza virus and a human influenza virus could lead to the emergence of a new influenza virus that is potentially highly contagious to humans.