Low- and Highly Pathogenic Avian Influenza a Viruses in Seal Population: A Brief Overview of 45-Years History

Genetically diverse influenza A viruses (IAV) circulates in wild aquatic birds with relatively frequent spillover (cases of single infections) to other mammals, but only a small proportion of outbreaks. The spillover of IAV to marine mammals such as seals have been reported throughout the last 45 years. Majority of these viruses when reached seals population cased pneumonia and death of infected animals. Until 2016, all avian influenza viruses found in seals were of low pathotype (LP) IAV. The H5Nx clade 2.4.4.4b highly pathogenic avian influenza viruses (HPAIV) were found in seals for the first time in 2016/2017. Our review highlights 45 years of AIV history in seals population, showing interesting features of different AIV subtypes and emphasis on avian-to-mammals transmission. Furthermore, we also included phylogenetic characterisation of the representative seal isolates.