Furthermore, as they are susceptible to both human and avian influenza viruses (3, 8, 10, 12), mink could also serve as mixing vessels for reassortment, a known pathway to pandemic emergence. A hypothetical route to co-infection is easy to envisage: Mink infected with avian influenza virus—which they acquired from being fed dead poultry or via exposure to wild birds—could become directly co-infected with human seasonal influenza transmitted to them from infected handlers. The last three influenza pandemics arose after the mixing of influenza genes among avian and human-origin strains, which are often thought to occur in a “mixing vessel” species. Swine are often cited as the vessel because pigs are susceptible to many avian and human strains. Pigs, however, are somewhat refractory to H5N1 infections, including the currently panzootic clade 2.3.4.4b viruses (13). Mink clearly are not. Mink farms could provide ample opportunity for the reassortment between H5 subtype avian influenza viruses and human-adapted strains.

Fur farming is banned across many European countries and North American states or territories. Several other regions have set dates for phasing it out. These bans have historically been a response to ethical concerns about the treatment of these animals. We strongly urge governments to also consider the mounting evidence suggesting that fur farming, particularly mink, be eliminated in the interest of pandemic preparedness. Fur farming should be in the same category of high-risk practices as the bushmeat trade and live animal markets. These activities all increase the likelihood of future pandemics. At the very least, biosecurity practices and active surveillance at fur farms must be reviewed, greatly enhanced, and closely enforced.