SARS-CoV-2 updates and testing guidance for veterinarians

March 5, 2021

SARS-CoV-2, the virus that causes COVID-19, is thought to spread mainly through close contact from person to person, including between people who are physically near each other (within about 6 feet). When people with COVID-19 cough, sneeze, sing, talk, or breathe they produce respiratory droplets. These droplets can range in size from larger droplets to smaller droplets, and small droplets can also form particles when they dry very quickly in the airstream. With passing time, the amount of infectious virus in respiratory droplets decreases, and smaller droplets and particles spread apart in the air.

COVID-19 can sometimes be spread by airborne transmission, although it is much more common for the virus that causes COVID-19 to spread through close contact with a person who has COVID-19. Some infections can be spread by exposure to the virus in small droplets and particles that can linger in the air for minutes to hours. These viruses may be able to infect people who are further than 6 feet away from the person who is infected or after that person has left the space. Airborne transmission seems most likely to occur within enclosed spaces with inadequate ventilation, especially when an infected person was breathing heavily, for example, while singing or exercising. Transmission from touching surfaces is not thought to be a common way that COVID-19 spreads.

People who are infected but do not show symptoms can also spread the virus to others. Cases of reinfection with COVID-19 have been reported but are rare. With certain variants of SARS-CoV-2, however, reinfection may be more of a concern.

Monitoring SARS-CoV-2 in animals

It is important to monitor infections in animals to better understand their epidemiological significance to the SARS-CoV-2 pandemic for animal health, biodiversity, and human health. Evidence from risk assessments, epidemiological investigations, and experimental studies indicates that animals do not play a significant role in the global spread of SARS-CoV-2. At the same time, it appears that the virus that causes COVID-19 can spread from people to animals in some situations. The Center for Disease Control & Prevention (CDC) is aware of a small number of pets worldwide, including cats and dogs, reported to be infected with the virus that causes COVID-19, mostly after close contact with people with COVID-19. Other species of farmed animals and wildlife have been naturally infected as well, and some additional species have been shown to be experimentally infected. There seem to be varying levels of susceptibility to infection among different species. At this time, the risk of SARS-CoV-2 spreading from animals to people is considered to be low. There is also no evidence that the virus that causes COVID-19 can spread to people from the skin or fur of pets.

As of February 24, 2021, 46 dogs and 67 cats have tested positive for SARS-CoV-2 in the United States (by Real Time (RT) -PCR). Minks, big cats (tigers, lions, snow leopard, cougar), and gorillas have also tested positive. Farmed mink have experienced several outbreaks worldwide, including at 16 facilities in the United States as of February 24, 2021, after suspected exposure to people with COVID-19. Some farms have experienced high mortality in mink, and there is some evidence that infected mink have transmitted SARS-CoV-2 ‘back’ to people.

Because there is a risk that people with COVID-19 could spread the virus to animals, CDC recommends that pet owners limit their pet’s interaction with people outside their household. Cats should be kept indoors when possible, and pets should not be allowed to roam freely outside. If a person inside a household becomes sick, the person should be isolated from all household members, including pets.

Animal Testing for SARS-CoV-2

Public health and animal health officials may decide to test certain animals that are showing signs consistent with a SARS-CoV-2 infection and that are known to have been exposed to the virus. The decision to test should be made using a One Health approach collaboratively between local, state, or federal public health and animal health officials. Testing guidance is available at www.cdc.gov/coronavirus/2019-ncov/php/animal-testing.html.

Routine testing of pets for SARS-CoV-2 is currently not recommended. Veterinarians are strongly encouraged to rule out other, more common causes of the illness before considering testing for SARS-CoV-2, especially among pets without a COVID-19 exposure.

Veterinarians who see animals that have a new, concerning illness and have been in a household with a person with COVID-19 or have had close contact with a person with COVID-19 should contact Public Health. The CDC has published criteria for evaluation and testing pets for SARS-CoV-2. Authorization for testing in Washington state will be conducted on a case by case basis by approval from the Washington State Department of Agriculture (WSDA) in coordination with the Washington State Department of Health.

***King County area veterinarians***

SARS-CoV-2 animal testing in the King County area can also be performed by referring pet owners and owners of congregate animal living facilities, such as an animal shelter, to the University of Washington COVID-19 and Pets Study (CAPS). Animals do not necessarily need to meet CDC SARS-CoV-2 testing criteria, but there does need to be proof of contact with a COVID-19 positive person. The CAPS study will sample dogs, cats, ferrets, and hamsters during a household visit. Study participation consists of a 15-30 minute online or phone survey administered to the pet/facility owner and a household visit by a CAPS veterinary team to sample all animals in the household. Testing is free of charge and the analyses are performed by the Washington Animal Disease Diagnostic Laboratory.

King County veterinarians working with owners whose pets meet CDC testing criteria but who are not interested in CAPS and do not have resources for testing may be eligible for testing through a Public Health – Seattle & King County animal surveillance testing grant. Please contact Dr. Beth Lipton at [email protected] or at (206) 263-8454.

Additional information and resources

For information on actions all pet owners should take to protect their pets from the SARS-CoV-2 virus and specific guidelines for sick pet owners, please visit https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/pets.html.
Veterinary facilities should use professional judgment in prioritizing or postponing certain procedures to maintain needed care while limiting staff and client person-to-person contact and conserving PPE. The AVMA has a resource for Minimizing COVID-19 Exposure and further information for veterinary clinics is available at https://www.cdc.gov/coronavirus/2019-ncov/community/veterinarians.html.
CDC has published PPE guidelines based on animal history that use a cautious approach given current limitations in knowledge.
Any animal specimen that tests positive at a laboratory other than a USDA National Veterinary Service Laboratory (NVSL) will need to be forwarded to NVSL for confirmatory testing. The CDC has published guidance for both home and veterinary facility isolations recommendations.