BASEL, Switzerland — A new study provides compelling evidence that coronavirus spreads between humans and animals. Researchers studying 16 mink farms in the Netherlands say that SARS-CoV-2, the virus that causes COVID-19, was not only transmitted from human to mink, but vice versa.
Just about nine months into this pandemic, the scientific community is still unsure about SARS-CoV-2’s exact origins. Some say bats, others pangolins. What is for sure, however, is the fact that many animals can indeed contract the novel coronavirus. This has been proven among primates, dogs, cats, bats, hamsters, rabbits, lions, tigers, and just recently – minks.
What makes this study so unique? The authors claim it’s the first to show proven animal-to-human SARS-CoV-2 transmission.
‘Strong evidence’ of farm workers contracting COVID from minks
This research was performed by a group of Dutch veterinary scientists. For each of the 16 farms studied, scientists performed a comprehensive analysis of both the minks on each farm and the humans working or living there. Researchers use whole genome sequencing for this process, which helps ascertain the sources of transmission.
Across all 16 farms, a total of 720,000 animals were included in the study. Meanwhile, 97 humans were tested as well. Among that group, 66 humans (67%) showed evidence of a COVID infection.
“Due to longitudinal follow up of the first 4 farms, we have strong evidence that at least two people on those farms were infected by minks. Unfortunately, based on our research we cannot make definite conclusions on the direction of most of the infections, so we do not know the total number of people that were infected by minks,” the study reads. “We conclude that initially the virus was introduced from humans and has evolved on mink farms, most likely reflecting widespread circulation among mink in the first SARS-CoV-2 mink farms, several weeks prior to detection.”
‘First proven zoonotic transmission of SARS-CoV-2 to humans’
A genetic analysis of SARS-CoV-2 samples taken from infected farm workers was identical to samples taken from minks. However, other samples taken from “unrelated SARS-CoV-2 patients living in the vicinity of farms” were not the same. This strongly suggests that people working directly with the minks contracted the coronavirus from those animals.
“Genetic sequences from each of the infected mink farms fell into one of five distinct clusters, showing transmission between different mink farms,” researchers write.
“Additional research will be needed to determine the routes of transmission. We conclude that at least some of these employees are very likely to have been infected directly from infected mink and thereby describe the first proven zoonotic transmission of SARS-CoV-2 to humans. Close collaboration between human and animal health departments is essential for early identification and control of SARS-CoV-2 infections,” the study concludes.
This research is set to be presented at the ESCMID Conference on Coronavirus Disease.