First Description of SARS-CoV-2 Infection in Two Feral American Mink (Neovison vison) Caught in the Wild

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19, is considered a pathogen of animal origin that is mainly transmitted from human to human. Several animal species can be naturally or experimentally infected by SARS-CoV-2, with compelling evidence that mink is highly susceptible to SARS-CoV-2 infection. Human-to-mink infection cases have been reported and there are also suggestions that mink-to-human infection occurs. Mink infections have been reported to date only on fur farms, except for one infected free- ranging wild mink near a Utah (USA) fur farm, which suggests a transmission pathway from farms to wild mink. We now report the detection of SARS-CoV-2 in 2 of 13 feral dark brown American mink (Neovison vison) trapped in the Valencian Community (Eastern Spain), during an invasive species trapping campaign. They were trapped in riverbeds in sparsely inhabited rural areas known to harbor self-sustained feral mink populations. The closest fur farm is about 20 km away. SARS-CoV-2 RNA was detected by two-step RT-PCR in these animals’ mesenteric lymph nodes and was confirmed by sequencing a 397-nucleotide amplified region of the S gene, yielding identical sequences in both animals. A molecular phylogenetic analysis was run on this sequence, which was found to correspond to the consensus SARS-CoV-2 sequence from Wuhan. Our findings appear to represent the first example of SARS-CoV-2 acquired in the wild by feral mink in self-sustained populations.

Hybridization of domestic mink with wild American mink (Neovison vison) in eastern Canada

Farmed American mink (Neovison vison (Schreber, 1777)) pose a risk to biodiversity owing to escape and release from farms. Feral mink may affect native species in locations where American mink are not endemic, such as Europe. In contrast, escaping domestic mink may hybridize with wild mink in North America, leading to introgression of domestic traits via hybrid-mediated gene flow. We tested this idea in eastern Canada, which has a history of mink farming. We sampled known domestic and free-ranging mink, and profiled 508 individuals at 15 microsatellite loci. We found that 33% of free-ranging mink were either escaped domestic individuals, domestic–wild hybrids, or were introgressed to domestic or wild parental groups. The greatest prevalence of free-ranging domestic, hybrid, or introgressed mink (59%) occurred in Nova Scotia, which also had the most mink farms. Historic (1980s or earlier) mink sampled from museums had higher allelic richness and private allelic richness than contemporary wild mink. Domestic mink are artificially selected for traits desired by farmers, and as such, introgression with wild mink may lead to a loss of local adaptation. Our findings demonstrate that continued escape and release of mink could pose risks to the maintenance of genetic integrity in wild mink.