Cats and COVID
contributed by Faith Morris
Throughout the COVID-19 pandemic and even today, there is controversy on the extent and impact of human-to-animal and animal-to-human transmission of SARS-Cov-2. The American Veterinary Medical Association (AVMA) made a statement regarding such concerns—that under natural conditions, it is rare for cats to get SARS-CoV-2 (AVMA Accessed 26 Mar. 2024). However, as felines live near their owners, it may be possible for humans to transmit the respiratory infection to cats without clinical signs. If we can find a direct correlation, it will open the doors to new ways of looking at transmission across species.
Our research article SARS-CoV-2 serosurvey of health, privately owned cats presenting to a New York City animal hospital in the early phase of the COVID-19 pandemic (2020-2021), takes a much closer look at the potential risk of indoor domesticated felines getting infected with SARS-CoV-2. This work was prompted by early findings that cats share high similarity to humans in their angiotensin-converting enzyme 2 (ACE2), the SARS-CoV-2 receptor. ACE2 is a receptor binding interface (RBD) that is widely present throughout the body. This enzyme is found in the heart, lungs, kidneys, and small intestine of humans. For felines, the enzyme can be found in the gastrointestinal mucosa (Hamming, I, et al 2004). ACE2 is important for understanding if/how SARS-CoV-2 can be transmitted to another animal species. As a respiratory virus, SARS-CoV-2 attaches to ACE2 to gain access to cells.
In collaboration with a veterinary practice in New York City (Choi et al. 2024) we sampled a population of 79 cats serologically, using a sensitive immunoassay, Multiplex Immunofluorescence (mIF), whcih is both highly specific and sensitive, and is a test that works by tagging antibodies of viral proteins that are found in plasma. mIF was modified to tag biomarkers in felines (Sheng W et al. 2021). Our test was set to look for Spike S1, Spike S2, RBD, and N protein in SARS-CoV-2. Because mIF uses plasma for its test, all of the felines in the study only had to give 2mL of blood to test for SARS-CoV-2. Of the 79 felines that were used in this study 44% were confirmed to be positive (Choi A et al. 2024) in the fall of 2020, a very high level considering the public health lockdown.
The research article opens up a new way to look at viral transmission events across species. In the article, they were able to show that felines can indeed get COVID-19, but more research should be done to determine transmission routes between humans and animals, and the impact of this on society.
References
- Hamming, I, et al. “Tissue Distribution of ACE2 Protein, the Functional Receptor for SARS Coronavirus. A First Step in Understanding SARS Pathogenesis.” The Journal of Pathology, U.S. National Library of Medicine, June 2004, www.ncbi.nlm.nih.gov/pmc/articles/PMC7167720/#:~:text=We%20have%20shown%20that%20ACE2,show%20this%20brush%20border%20staining.
- “SARS-COV-2 in Animals.” American Veterinary Medical Association, www.avma.org/resources-tools/one-health/covid-19/sars-cov-2-animals-including-pets. Accessed 26 Mar. 2024.
- Sheng W, Zhang C, Mohiuddin TM, Al-Rawe M, Zeppernick F, Falcone FH, Meinhold-Heerlein I, Hussain AF. Multiplex Immunofluorescence: A Powerful Tool in Cancer Immunotherapy. Int J Mol Sci. 2023 Feb 4;24(4):3086. doi: 10.3390/ijms24043086. PMID: 36834500; PMCID: PMC9959383.
- Putlyaeva, Lidia. Overview of SARS-CoV-2 Life Cycle. 18 July 2021. Studying SARS-CoV-2 with Fluorescence Microscopy, NIH, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8234815/. Accessed 14 Mar. 2024.
- Choi A, Stout AE, Rollins A, Wang K, Guo Q, Javier AJ, Kennedy M, Wagner B, Whittaker GR. SARS-CoV-2 serosurvey of healthy, privately owned cats presenting to a New York City animal hospital in the early phase of the COVID-19 pandemic (2020-2021). bioRxiv [Preprint]. 2024 Feb 15:2024.02.13.580068. doi: 10.1101/2024.02.13.580068. PMID: 38405835; PMCID: PMC10888843.
Do cats pose a risk to our Health?
February 14, 2024
Cats—both big and small—are an enormous part of our lives and have significantly contributed to history and society as we know it. However, we need to keep in mind that the animal companions that we hold near and dear could also pose a health risk.
New feline coronavirus blamed for thousands of cat deaths in Cyprus
Now, researchers have identified a possible culprit: a new strain of feline coronavirus that has coopted key RNA sequences from a highly virulent dog pathogen called pantropic canine coronavirus (pCCoV). The findings, posted as a preprint on bioRxiv by collaborators in the UK and Cyprus, could help explain how severe illness managed to spread so widely among cats on the island; see https://www.biorxiv.org/content/10.1101/2023.11.08.566182v2
“They’ve done a great job in identifying what looks to be a very interesting and concerning virus,” says Gary Whittaker, a virologist at the Cornell University College of Veterinary Medicine ( see; https://www.science.org/content/article/new-feline-coronavirus-blamed-thousands-cat-deaths-cyprus) . Although canine-feline coronavirus crossovers have been reported before, he says, this is the first documented case of a cat coronavirus combining with pCCoV, apparently leading to a “perfect storm of both disease and transmissibility.”
Managing Microbes: Antibiotic and Anti-viral Stewardship
August 25, 2022
Antimicrobial stewardship isn’t just about antibiotics. Viral evolution is rapid in response to outside pressures and advances in antiviral drugs mean it is increasingly important that we understand how to be good stewards of these important antimicrobials.
Getting to the heart of the matter
March 24 2021
Its been a year since SARS-CoV-2 was documented in tigers in the Bronx Zoo. In the intervening time, data has been trickling in on how COVID-19 affects cats. We share what we’ve been watching and our thoughts on what may be coming next.
COVID-19 and Wildlife: A One Health Perspective
Dec 9 2020
People aren’t the only species that can be infected with COVID-19. What can we do to prevent spill-over into wildlife populations? Keeping our feline companions indoors helps keep them out of harms way while safeguarding native species.
Nov 13 2020
Much ado about mink
What’s happening with Denmark’s mink farms and what does it mean for the SARS-CoV-2 pandemic? Laura Goodman and Gary Whittaker tackle the problem of mutant viruses in this week’s blog.
Nov 1 2020
Rethinking feline coronavirus outcomes
Dr. Alison Stout writes a compelling letter to JAVMA outlining the similarities between FIP and COVID-19. Although the viruses that cause these diseases are distinct, some of the outcomes are strikingly similar. Approaching the pandemic from a one heath perspective can enhance our understanding of coronaviral infections and lead to advances in human and animal health. SARS-CoV-2 is not limited by species bounds and we should not limit our understanding of this global crisis to the human sphere.
This letter to the editor was published in JAVMA on November 1, 2020. It is openly available on Cornell’s eCommons where it has been reprinted with the permission of the AVMA.