HPAI A(H5N1) virus infection in farmed minks, Spain, October 2022
Last October we report an outbreak of Avian H5N1 in a Mink farm in Spain. Now the journal Eurosurveillance provides a detailed report on the outbreak. This is the first report of clade 2.3.4.4b HPAI H5N1 virus infection of minks farmed for their fur in Europe. The minks were fed with raw fish and poultry by-products, cereals, and blood meal. Poultry farms and avian slaughterhouses supplying the poultry by-products were located in Galicia. Up to 10 January 2023, H5N1 poultry outbreaks have not been reported in this region.
The viruses identified presented the highest similarity with strains of the A/gull/France/22P015977/2022-like genotype, which has already been described in multiple wild bird species and sporadically in poultry across northern Europe. However, the viruses detected at the mink farm are distinguished from all the clade 2.3.4.4b H5N1 viruses characterised thus far in the avian population in Europe as they bear an uncommon mutation (T271A) in the PB2 gene, which may have public health implications. The same mutation is present in the avian-like PB2 gene of the 2009 pandemic swine-origin influenza A(H1N1) virus (H1N1pdm).
