ARTICLE | doi:10.20944/preprints202308.1579.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: highly pathogenic avian influenza A H5N8; clade 184.108.40.206b; Kosovo; domestic poultry; phylogenetic network analysis; viruses; persistent circulation
Online: 22 August 2023 (12:59:41 CEST)
In this study, we report the first outbreak of highly pathogenic avian influenza (HPAI) A H5N8, clade 220.127.116.11b in Kosovo on May 19, 2021. The outbreak consisted of three temporal phases: May–June 2021, September–November 2021, and January–May 2022. In total, 32 backyard and 10 commercial holdings tested positive for the virus, affecting 179,198 poultry. Interestingly, the third and last phase of the outbreak coincided with the massive H5N1 clade 18.104.22.168b epidemic in Europe. Phylogenetic analyses of 28 viral strains from Kosovo revealed that they were closely related to the H5N8 clade 22.214.171.124.b viruses that have been circulating in Albania, Bulgaria, Croatia, Hungary, and Russia in early 2021. Whole genome sequencing of the 25 and partial sequencing of 3 H5N8 viruses from Kosovo showed high nucleotide identity, forming a distinctive cluster and suggesting a single introduction. The results of the network analysis were in accordance with the three epidemic waves and suggested that the viral diffusion could have been caused by secondary spreads among farms and/or different introductions of the same virus from wild birds. The persistent circulation of the same virus over a one-year period highlights the potential risk of the virus becoming endemic, especially in settings with non-adequate biosecurity.