Poland: Cat deaths due to H5N1 – no link with waterfowl

On 22 June 2023, numerous cat deaths were documented by Polish media, reported ABCD member Tadeusz Frymus. The previous week, several feline cases of an acute, or peracute, disease had been reported. These fatal cases had presented initially with dyspnoea, pulmonary consolidation and neurological signs.

Subsequently, Poland’s Chief Veterinary Officer reported that infection with H5N1 avian influenza virus had been confirmed in several of the cats that had died, although the strain was not identical to the strain identified recently in waterfowl on the Baltic coast. The confirmed cases of H5N1 avian influenza included cats from different locations: Gdansk, Gdynia, Pruszcz Gdanski, Bydgoszcz, Poznan, Lublin and Warsaw.

On 5 July 2023, ProMED reported that the H5N1 avian influenza viruses from cats analyzed so far originate from a single, unidentified source, related to the H5N1 viruses circulating in wild birds in recent weeks in Poland.

Attempts to treat the affected cats have included the use of broad-spectrum antibiotics, anti-viral feline interferon omega (Virbagen Omega, Virbac), L-arginine supplementation, vitamin D, oxygen supplementation (such as via a tent, if available), as well as other supportive treatment.

The influenza virus is an enveloped virus, which is susceptible to heat, all common disinfectants as well as ultraviolet light (including sunshine).  Indirect transmission can occur; therefore, it is important to clean and disinfect hands and any surfaces that have been exposed to an infected cat (e.g., examination tables, cat carriers, etc).

ABCD is monitoring the situation closely. In the meantime, we suggest that cat owners should be advised to keep their pets indoors (if possible, although ABCD recognises that this can cause undue stress in animals used to having outdoor access), to prevent contact between cats and wild animals, particularly birds, and to avoid feeding raw food.

The ABCD guideline Influenza Virus Infections in Cats is available at https://www.abcdcatsvets.org/guideline-for-influenza-virus-infections-in-cats/ and was last reviewed on 5 June 2023.