#17,527
After a weekend offering little official news, this morning we have a brief, initial analysis of the H5N1 virus that has been detected in sick and dying cats in numerous cities across poland for the past 2 weeks.
This report finds the (n=9) viruses sampled thus far are closely related, have previously appeared in poultry and wild birds in Poland, all belong to genotype CH, and are most closely related to a sample detected in a White Stork in June.
Missing from this report is any mention of amino acid changes (mutations) that might signal increased adaptation to mammals. Something that has been reported in other feline infections (see EID Journal: HPAI A(H5N1) Clade 2.3.4.4b Virus in Domestic Cat, France, 2022).
This possibility was mentioned in last Friday's ECDC Risk Assessment (see excerpt below).
Media sources from Poland cite the director of the National Veterinary Institute in Puławy stating that "they have detected two mutations that indicate that the A(H5N1) virus is evolving to multiply more easily in mammals".
I expect we'll get a more detailed analysis in the next couple of days. In the meantime, while a single source has been implicated, it still isn't clear how both indoor and outdoor cats from across a wide swath of Poland are contracting the virus.
The translated Statement follows.Results of genome sequence analysis of highly pathogenic avian influenza (HPAI) viruses, H5N1 subtype, detected in nine cats from Poznań, Tri-City and Lublin
All analyzed feline viruses are very closely related to each other and, according to the nomenclature used by the EU Reference Laboratory (EURL) in Padua, belong to the CH genotype. This genotype dominated at the peak of the current avian influenza season (2022/23) and was found mainly in poultry in the province of Wielkopolska, as well as in wild birds in various regions of the country. Recently, a virus belonging to the CH genotype was detected in a white stork at the beginning of June in the Tarnów district (outbreak No. 119/2023) and it is to it that the strains derived from cats are most closely related.This indicates that the feline H5N1 avian influenza viruses analyzed so far originate from a single, unidentified source, related to the H5N1 viruses circulating in wild birds in recent weeks in Poland. In addition,National Veterinary Institute - National Research Institute cooperates with EURL, the European Food Safety Authority (EFSA) and the European Center for Disease Prevention and Control (ECDC) in the field of more detailed molecular analysis of detected viruses and assessment of zoonotic potential.
