#16,247
Although SARS-CoV-2 is primarily an infection threat to humans, it appears to have emerged from wild animals (see Science Perspective: The Animal Origin of SARS-CoV-2), and so it isn't unreasonable to worry that it could establish itself in non-human species as well.
A robust, secondary, reservoir of COVID could provide the virus with new evolutionary pathways, with the ongoing risk of spillover back into humans of new variants.
When MERS-CoV emerged in 2012 (from camels) we looked at a lot of research on what other animals, including livestock, might be susceptible to the virus (see Emerg. Microbe & Inf: MERS Infection In Non-Camelid Domestic Mammals). Luckily, common farm animals like poultry, cattle, horses, and swine were not susceptible.
However, in Alpacas have been found with MERS-CoV antibodies.
SARS-COV-2, however, has shown a much broader host range, with dogs, cats, mink, and ferrets all showing varying degrees of susceptibility (see COVID Variant B.1.1.7 & Companion Animals. Last July, we also looked at a spillover from humans to deer (see USDA/APHIS: White-Tailed Deer Exposed To SARS-CoV-2 Detected In 4 States).
Perhaps of greatest concern, in November of last year Denmark announced the discovery of a mutated SARS-CoV-2 virus in both Mink and in humans, prompting authorities to order the depopulation of 17 million mink (see Denmark Orders Culling Of All Mink Following Discovery Of Mutated Coronavirus).
In response, Denmark temporarily locked down North Jutland, where most of the human cases had been identified, and the UK quickly banned travel to and from Denmark.
Actually, there were multiple `mink variant's' (B.1.1.298 lineage), but only one - dubbed `Cluster 5' - appeared to pose any enhanced threat over the `wild type' COVID (see EID Journal: SARS-CoV-2 Transmission between Mink (Neovison vison) and Humans, Denmark).
Although spreading widely in Denmark as late as October, `Cluster 5' proved to be not nearly as transmissible as many of its competitors, and it quickly gave way to more biologically `fit' COVID variants (including, eventually, Alpha). .
Two weeks ago, in CCDC Weekly Perspectives: COVID-19 Expands Its Territories from Humans to Animals, we looked at concerns in China over the continual spread of SARS-CoV-2 from humans to other animal hosts, and the impacts that could have going forward.
While a variety of other coronaviruses are known to infect, and transmit efficiently, among birds (IBV), swine (PED & TGE), and cattle (BCoV), reassuringly the evidence continues to suggest that common livestock (poultry, swine, cattle, etc.) are not particularly susceptible to SARS-CoV-2 infection (see EID Journal: Susceptibility of Domestic Swine to Experimental Infection with SARS-CoV-2).
All of which brings us to a press release from the USDA ARS (Agricultural Research Service) which further confirms the current low risk of infection to livestock, and the finding in deer.
Farm Animals Tested for COVID Susceptibility
Oct 11th, 2021
Scientists and staff at the Agricultural Research Service (ARS) have been studying Covid-19 for over a year-and-a-half to ensure that America’s agricultural system is safe.
“ARS implemented emergency research in February 2020 in response to COVID-19 incursions in the United States,” said Cyril Gay, ARS senior national program leader for animal production and protection. “The aim of the research was to confirm that farm animals were not susceptible to the SARS-CoV-2 virus and remove potential concerns of farm animals becoming infected and transmitting the virus to people through direct contact or through agricultural products.”
ARS has laboratories and personnel dedicated to the research of especially dangerous pathogens, including emerging zoonotic agents such as SARS-CoV-2. COVID-19 is the term used for the disease, while SARS-CoV-2 is the acronym for the name of the viruses that causes COVID-19.
“ARS research clearly provided science-based evidence that eggs and live poultry, cattle, swine, and arthropods (mosquitoes, ticks, flies, fleas, spiders, etc.), were not able to replicate the virus and become a source of infection for people,” Gay said. Of all the farmed animals studied, only deer were susceptible to SARS-CoV-2. “Interestingly, deer did not get sick, but they quickly spread the virus to other deer.”
ARS implemented emergency research in response to COVID-19 in February 2020, and their research provided science-based evidence that eggs and live poultry, cattle, and swine were not able to replicate the virus and become a source of infection for people. (Photos by Keith Weller, K3627-16 and K4328-8) (Photo by Scott Bauer, K7623-1)
ARS included white tail deer in its investigation because the genetic sequence of the SARS-CoV-2 virus cell receptor closely aligns with the sequence of the human receptor, and because some white tail deer are farmed.
As the United States and the rest of the world reeled from the effects of a global pandemic, ARS researchers from the National Animal Disease Center, in Ames, IA; the National Poultry Research Center, in Athens, GA; and the Arthropod-Borne Animal Disease Research Unit, in Manhattan, KS, braved the then-unknown dangers of COVID-19. Researchers followed health and safety protocol guidelines issued by the Centers for Disease Control and Prevention to ensure their safety as well as the safety of ARS support staff and collaborators.
ARS has a long history of implementing emergency research in response to disease outbreaks. Recent examples include the pandemic H1N1 in 2009 and a highly pathogenic avian influenza virus outbreak in 2014-2015. USDA is a key contributor to our nation’s National Biodefense Strategy, closely with public health agencies to effectively respond and mitigate emerging zoonotic pathogens that pose a threat to the health of people and farm animals.
“A critical aspect of our job is to respond rapidly and implement emergency research on a disease outbreak and quickly test or develop veterinary medical countermeasures to prevent and control the spread of the disease,” Gay said. “By mitigating the impact of diseases, we lower the threat it could cause to U.S. agriculture, our economy, and our citizens.”
– By Scott Elliott, ARS Office of Communications
