H5N1/HPAI avian influenza in a mink farm in Spain

The researchers of the European Reference Laboratory for Avian Influenza at the Istituto Zooprofilattico Sperimentale delle Venezie, in collaboration with colleagues of the National Reference Laboratory for Spanish avian influenza in Madrid, and the Spanish Health Authorities, have identified a highly pathogenic avian influenza H5N1 virus in a fur mink farm in north-west Spain.

The results of epidemiological, clinical and genetic investigations have been published in the scientific journal Eurosurveillance.

The facts date back to October 2022 when, following a sudden increase in mortality in a fur mink farm, samples taken from symptomatic animals were sent to the Spanish laboratories for analysis.

The analysis revealed the presence of H5N1/HPAI virus.

At the moment it is unknown the mechanism of introduction and spread of the virus in the farm. However, given the mortality of wild sea birds in the same region in the previous weeks caused by the H5N1/HPAI virus, researchers speculate that the virus was introduced by wild birds.

The mechanisms for spreading the virus in the farm and the methods of transmission between the minks remain to be studied. Further studies are underway to characterize the virulence and transmissibility of the virus.

Genetic analysis has established that the virus belongs to a well-known viral group responsible for the serious avian influenza epidemic that has been taking place for over two years in domestic and wild birds in Europe and worldwide.

Although the virus identified in mink is distinct from the strains described so far in European birds for some mutations in its genome, it is stressed that none of the mutations detected are among those known to make an H5N1/HPAI virus transmissible effectively from man to man.

Source: IZSVe