SARS-CoV-2 Outbreak on a Spanish Mink Farm: Epidemiological, Molecular, and Pathological Studies.

Bernardino Moreno,Marina Betancor,Iñaki Comas,Eva Monleón,Juan José Badiola,Mirta García Martínez,Sonia Pérez Lázaro,Rosa Bolea,Jenny Lozada,Alicia Otero,Eloisa Sevilla,Carolina Velez,Diego Sola,Cristina Acín,Marta Monzón,Belén Marín,Álvaro Chiner-Oms,Irving Cancino-Muñoz

doi:10.3389/fvets.2021.805004

Abstract

Farmed minks have been reported to be highly susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and may represent a risk to humans. In this study, we describe the first outbreak of SARS-CoV-2 occurred on a mink farm in Spain, between June and July 2020, involving 92,700 animals. The outbreak started shortly after some farm workers became seropositive for SARS-CoV-2. Minks showed no clinical signs compatible with SARS-CoV-2 infection throughout the outbreak. Samples from 98 minks were collected for histopathological, serological, and molecular studies. Twenty out of 98 (20.4%) minks were positive by RT-qPCR and 82 out 92 (89%) seroconverted. This finding may reflect a rapid spread of the virus at the farm with most of the animals overcoming the infection. Additionally, SARS-CoV-2 was detected by RT-qPCR in 30% of brain samples from positive minks. Sequencing analysis showed that the mink sequences were not closely related with the other mink SARS-CoV-2 sequences available, and that this mink outbreak has its probable origin in one of the genetic variants that were prevalent in Spain during the first COVID-19 epidemic wave. Histological studies revealed bronchointerstitial pneumonia in some animals. Immunostaining of viral nucleocapsid was also observed in nasal turbinate tissue. Farmed minks could therefore constitute an important SARS-CoV-2 reservoir, contributing to virus spread among minks and humans. Consequently, continuous surveillance of mink farms is needed.

Highlights

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19), a declared pandemic that has affected more than 150 million people worldwide [1].Natural SARS-CoV-2 infections have been documented in domestic dogs, felids, and mustelids
The first positive mink was detected on 21st of May in an adult female which had not died of a respiratory pathology
Further studies carried out on 97 culled minks showed that 19 additional animals were positive by reverse transcription quantitative PCR (RT-qPCR) in nasal turbinates [20.4% total prevalence]

Summary

Introduction

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19), a declared pandemic that has affected more than 150 million people worldwide [1]. Natural SARS-CoV-2 infections have been documented in domestic dogs, felids, and mustelids. To date only farmed minks (Neovison vison) have been shown to be SARS-CoV-2 in Spanish Minks susceptible to a natural infection, and to develop severe illness and transmit SARS-CoV-2 to other minks and humans [2]. Europe is the global leader in fur production, with ∼2,750 mink farms [3]. Farming conditions could contribute to virus spread among minks, as they are kept in large groups and housed with bedding that generates dust [4]. Since SARS-CoV-2 infection in farmed minks was first identified in The Netherlands in April 2020, it has been reported on mink farms from other countries, including the USA, Denmark, Spain (the present case), France, Italy, Sweden, Canada, Greece, Lithuania, and Poland [5]

Methods

Results

Conclusion