Research shows that SARS-CoV-2 travels between animals and humans on mink farms

A detailed study of outbreaks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on 16 mink farms by Dutch researchers suggests that mink may serve as a reservoir for persistent human infections Became clear. Research is currently available bioRxiv* Preprint server.

The origin of the zoonotic pandemic of coronavirus disease (COVID-19) caused by SARS-CoV-2 is unknown so far. Animal studies have shown that nonhuman primates, ferrets, cats, rabbits, hamsters, and bats can be infected with this virus.

The most recent introduction to this zoo is farmed mink. More specifically, mink infection was observed on several farms in the Netherlands, but airborne inhalable dust particles in mink houses were found to contain SARS-CoV-2 genetic material. ..

The virus was first diagnosed on April 23 and April 25, 2020 on two mink farms in the Netherlands. After the virus was first detected on these farms, an in-depth investigation was initiated to look for potential routes of infection and conduct a professional investigation. And environmental risk assessment.

In this new study, Dutch researchers from various institutions conducted a detailed study of SARS-CoV-2 outbreaks in mink farms and employees of mink farms in the Netherlands, providing survey data, epidemiologic information, and whole-genome sequencing. Combined human and animal interface.

Geographical overview of SARS-CoV-2 positive mink farms by affected municipalities. The ratio of SARS-CoV-2 positive mink farms to total mink farms (CBS, 2019) is shown. The positive farm symbol is color-coded for each cluster and the shape indicates farms with the same owner.

From initial detection to whole genome sequencing

Farmers from 16 mink farms that are SARS-CoV-2 positive were contacted by local government health services to conduct a survey, and the samples were submitted for reverse transcription polymerase chain reaction (RT-PCR) and serology. Collected for diagnosis.

Researchers selected all nearly full-length Dutch SARS-CoV-2 genomes available in the national database (1,775 total) available on July 1, 2020, and MUSCLE (by multiple sequence comparisons) log-expectation).

In addition, whole-genome sequencing was also performed on 34 SARS-CoVs to distinguish between mink farm-related SARS-CoV-2 infections and locally acquired infections and to identify potential risks to people living near mink farms. Performed-two positive samples from people living in the same postal code area on the first four mink farms.

High sequence diversity in the SARS-CoV-2 genome

This study clearly shows ongoing SARS-CoV-2 infections on mink farms, but has also identified specific transmission events in humans. A total of 68% of the tested farm workers, their relatives, or contacts were shown to be infected with the virus. This indicates that contact with minks infected with SARS-CoV-2 is a risk factor for COVID-19 infection.

Also, Phylogenetic analysis We revealed that 16 farm mink sequences in the mink SARS-CoV-2 genome can be grouped into 5 different clusters. Based on currently available data, there were no clear differences in the symptoms of animal or human disease between the clusters.

However, high diversity of sequences from several mink farms has been observed. This may be due to animals being infected for generations before the mortality spike.

Animal surveillance as a privilege

“To our knowledge, these are the first recorded animal-to-human SARS-CoV-2 infection events,” the study authors say. “We have further researched mink and other Mustelidae species to show whether these species could be true reservoirs for SARS-CoV-2.

Following the observations in this study, SARS-CoV-2 infection was also revealed on mink farms in Spain, Denmark, and the United States. In addition, it is important to emphasize that mink aquaculture is also prevalent in other parts of the world, especially in China where about 26 million mink furs are produced each year.

“At the moment, despite ongoing strengthening of biosecurity, early warning surveillance, and immediate selection of infected farms, transmission is ongoing among mink farms with three large epidemic clusters of unknown transmission pattern.” bioRxiv Investigation.

In conclusion, the structure and population of mink farms opens the door to a sustainable circulation of SARS-CoV-2 after its first introduction. Therefore, careful monitoring and collaboration between human and veterinary health services/specialists is crucial to prevent animals from functioning as reservoirs for ongoing human infections.

The number of mink farms per municipality in the Netherlands. Summary of the total number of mink farms by municipality (CBS, 2019). Municipalities with farms affected by SARS-CoV-2 by June 21, 2020 are shown in red.

*Important Notices

bioRxiv It publishes preliminary non-peer reviewed scientific reports and should not be considered conclusive and should not guide clinical practice/health-related behaviors or be treated as established information.