Poland: Raw poultry meat most likely source of H5N1, case report shows

In June 2023, numerous cat deaths were documented by Polish media, reported ABCD member Tadeusz Frymus. 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, highly pathogenic avian influenza H5N1 virus was identified as the cause of these cases (doi.org/10.2807/1560-7917.ES.2023.28.31.2300366). The clinical course, diagnostic methods, including lung ultrasound examination, and results of laboratory tests have been described in detail for one of these patients. (doi.org/10.3390/microorganisms11092263). Poland’s Chief Veterinary Officer reported that until 17 July 2023, H5N1 infection had been confirmed in 33 domestic cats and one captive caracal. However, later the number of affected animals increased, with infected single ferrets and dogs also being identified. The confirmed cases included cats from different locations: Gdansk, Gdynia, Pruszcz Gdanski, Bydgoszcz, Poznan, Lublin and Warsaw.

The source of this infection is not clear. However, in one case raw poultry meat contaminated with H5N1 virus was the most probable cause (doi: 10.3201/eid1502.080949) and many of the affected cats had been fed raw meat or had access to leftovers.

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 continues to monitor the situation. In the meantime, we suggest that cat owners should be advised to keep their pets indoors in areas where avian influenza H5N1 virus has been detected (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.