A strain of the avian flu, which has devastated bird populations, appears to have found a new host.
According to a report published in the medical journal Eurosurveillance, the H5N1 strain was discovered in mink at a farm in Spain.
Two animals were initially tested for COVID-19, but the test results came back negative. Subsequent tests for the avian flu returned a positive result.
The report says the farm had over 50,000 minks, and within weeks the entire premises were affected by the virus.
Researchers have not definitively confirmed how the virus was initially transmitted, but they speculate wild birds were likely the source.
This isn't the first time the highly transmittable H5N1 virus has been detected in mammals. The Department of Agriculture notes that the virus has been found in raccoons, bears and skunks in the U.S.
However, the report in Eurosurveillance notes that mink could serve as a "potential mixing vessel for the interspecies transmission" among birds, mammals and even humans.
The Centers for Disease Control currently says H5N1 is "primarily an animal health issue." However, it notes that it's monitoring the situation closely and taking preventative measures should it pose a greater risk to human health.
The CDC notes that a small number of humans have contracted H5N1 in the past, but there are no known cases of human-to-human spread.