The Effect of COVID-19 on Animals
Written by: Catherine Kawaja ‘24
Edited by: Max Ulibarri ‘23
Source: Pollak, S. All Passengers From Denmark to Restrict Movements Amid Concern Over COVID-19 Mink Strain. The Irish Times [Internet]. November 7, 2020 [December 22, 2020]. Available from: https://www.irishtimes.com/news/health/all-passengers-from-denmark-to-restrict-movements-amid-concern-over-covid-19-mink-strain-1.4403493
On November 4th, the Denmark government made the horrifying proclamation that all farmed mink in the country will be killed to prevent further spread of new coronavirus strains that have appeared on Danish mink farms. Since June, mink with newly emerged coronavirus strains have infected more than 200 people. Many of the mink-related variants of the virus include a new, possibly dangerous mutation called “Cluster 5,” which has the potential to interfere with the efficacy of vaccines currently being developed because it changes the physical characteristics of the virus. Although the decision to slaughter millions of mink might seem drastic, the potential outcomes of a mink-related outbreak are threatening to the management of this pandemic.
However, mink are not the only animals that transmit COVID-19. How can scientists determine which animals are susceptible, and how can they deal with them? Scientists and the government must take into account the risk of potential mutations of the virus, safety concerns for those who come into contact with animals, and the health of the animals themselves.
In an article published by Science Magazine in May 2020, a group of scientists investigated the “Susceptibility of Ferrets, Cats, Dogs, and Other Domesticated Animals to SARS-Coronavirus 2.” The virus was introduced to the animals in different ways to understand three main questions: whether or not the virus can replicate in the host animal, the severity and how it infects those who are susceptible, and whether it can be transmitted to other animals of the same species.
The ferrets were given the virus intranasally and observed over two weeks using nasal washes, rectal swabs, temperature checks, and general monitoring of symptoms. Virus was detected in the nasal washes of all of the ferrets from days 2-8. Additionally, two out of six ferrets developed fever and a loss of appetite on days 10 and 12. After finding no viral RNA in the other tissues or organs, this portion of the study ended with the conclusion that SARS-CoV-2 can replicate in the upper respiratory tract of ferrets for up to 8 days without causing severe disease or death. This means that ferrets could be a potential risk along with the minks in Denmark.
Cats were similarly infected with the virus, and the results showed SARS-CoV-2 could replicate effectively, which means that they could also be a public health risk like the minks. Furthermore, after placing three infected cats next to three healthy cats, one exposed, healthy cat became infected through respiratory droplet transmission. This showed SARS-CoV-2 to be transmissible via the airborne route for cats. In contrast, dogs were found to have low susceptibility to the virus. Although four dogs were infected, only two of them were found to have viral RNA, and infectious virus wasn’t detected in any of the dogs. Proving this, the two contact-exposed dogs tested negative for SARS-CoV-2. This suggests dogs are at lower risk of mutating and spreading a new strain of coronavirus. In the pig, chicken, and duck study, neither the infected or contact animals were at all susceptible to SARS-CoV-2.
Although this article helps begin to answer the question of certain animals’ susceptibility to the virus, it fails to provide a definitive path forward to address the issue of animals being infected with SARS-COV-2. Should governments take drastic measures like Denmark to eradicate animals that become infected? Would it be worth minimizing mutation risk to eradicate ferrets, or even cats? Where is the line drawn? The answer to this ethical dilemma will require additional research and will likely be difficult to ascertain.
 Shi, J; Wen, Z; Zhong, G; Yang, H; Wang, C; Huang, B; Liu, R; He, X; Shuai, L; Sun, Z; Zhao, Y; Liu, P; Liang, L; Cui, P; Wang, J; Zhang, X; Guan, Y; Tan, W; Wu, G; Chen, H; Bu, Z. Susceptibility of Ferrets, Cats, Dogs, and Other Domesticated Animals to SARS-Coronavirus 2. Science Magazine [Internet]. 2020 [December 22, 2020]; Vol. 368, (Issue 6494), pp. 1016-1020. DOI: 10.1126/science.abb7015
 Fischer, L. The Real Danger Posed by Coronavirus-Infected Mink [Scientific American] [Internet] [November 11, 2020]. Available from:
 Pollak, S. All Passengers From Denmark to Restrict Movements Amid Concern Over COVID-19 Mink Strain. The Irish Times [Internet]. November 7, 2020 [December 22, 2020]. Available from: https://www.irishtimes.com/news/health/all-passengers-from-denmark-to-restrict-movements-amid-concern-over-covid-19-mink-strain-1.4403493
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