Mink Outbreak Points to Wild Virus Source.

Mink in three Polish farms tested positive for SARS-CoV-2, carrying a strain not seen in humans in the region for over two years, suggesting another unknown species may have been harboring and spreading the virus. Researchers suspect that wild animals, such as martens, feral cats, or escaped mink, could have cryptically spread the virus and introduced it to the mink farms. The finding highlights the risk of viral "spillback," where the virus could periodically move back to humans from an animal population that could become a new reservoir.