The question of whether pets can get COVID-19 and if it can be fatal is a significant concern for many pet owners. Recent research has shed light on the susceptibility of cats and dogs to SARS-CoV-2, the virus that causes COVID-19 in humans. A study published in Emerging Infectious Diseases investigated the risk of SARS-CoV-2 infection in pets living with infected owners, providing valuable insights into this issue.
While it’s known that various animal species, particularly cats and dogs, can contract SARS-CoV-2, it’s important to understand the severity and potential outcomes of these infections. Pets are often in close proximity to humans, making them potentially more exposed to the virus. Studies have shown that under experimental conditions, pets can become infected, but these infections are typically transient and result in mild symptoms.
Veterinarian examining a cat during a study on SARS-CoV-2 infection in pets, highlighting research on COVID-19 risks for cats and dogs
In rare instances, animal deaths have been reported following SARS-CoV-2 infection. However, determining the direct contribution of the virus to these deaths can be complex. Although the primary source of infection in pets is usually their human owners, the specific risk factors for this transmission, along with the characteristics and frequency of illness in pets, have not been fully understood until recently.
Key Findings on SARS-CoV-2 in Pets from a Canadian Study
To gain a clearer picture of SARS-CoV-2 infection in domestic animals, researchers conducted a study in Ontario, Canada, focusing on household pets and animals in shelters and neuter clinics. The study aimed to determine the seropositivity rate of SARS-CoV-2 in these animal populations and identify household risk factors associated with infection.
Veterinarians involved in the study invited pet owners who had been diagnosed with COVID-19 within the previous three weeks to bring their dogs, cats, and ferrets for sample collection between April 2020 and August 2021. Samples were collected from the nasal passages, oral cavity, and rectum of the animals. The median age of the dogs and cats participating in the study was five and six years, respectively.
Initial testing involved a quantitative reverse transcription-polymerase chain reaction (RT-qPCR) to detect the virus in the swab samples. Samples that tested positive for the SARS-CoV-2 nucleocapsid (N1) gene underwent further analysis through whole-genome sequencing (WGS). Blood samples were also collected from pets of COVID-19-infected owners to detect antibodies (IgG and IgM) against the SARS-CoV-2 spike (S) protein using an enzyme-linked immunosorbent assay (ELISA). A subset of serum samples was further analyzed using a surrogate virus neutralization test (sVNT) to assess the blocking of interaction between the virus’s receptor-binding domain (RBD) and the ACE2 receptor. Pet owners also completed online surveys providing details about their household, interactions with their pets, and any illnesses observed in their animals.
The study analyzed 283 swab samples from pets. RT-qPCR testing revealed that six animals were positive for SARS-CoV-2. Whole-genome sequencing of two positive cat samples identified virus lineages B.1.2 and A.23.1, which were similar to human SARS-CoV-2 sequences circulating in the same region. Serological analysis indicated a seropositivity rate ranging from 25% to 48% for IgG and IgM antibodies, suggesting prior exposure to SARS-CoV-2 in a significant proportion of pets.
Risk factor analysis revealed a statistically significant correlation between seropositivity in dogs and the onset of respiratory illness in the pet when the owner had COVID-19. For cats, sleeping in the owner’s bed was identified as a significant risk factor for seropositivity. In dogs, licking the hands or face of owners was associated with a higher risk of seropositivity.
Understanding the Severity and Risk of Fatal Outcomes in Pets
The study confirmed that SARS-CoV-2 can transmit from infected humans to pets. However, PCR detection indicated that the infection in pets is typically short-lived and transient, aligning with experimental observations in cats. The higher seropositivity rate compared to PCR positivity suggests that many pets are exposed to the virus and develop antibodies without showing severe or prolonged illness.
While cat-to-cat transmission of SARS-CoV-2 is known to occur, the risk of cats transmitting the virus back to humans remains unclear. The findings emphasize the importance of further research to fully understand the implications of SARS-CoV-2 spillback into pet populations for both animal and human health.
Regarding the question of pet deaths from COVID-19, it’s crucial to note that severe outcomes are exceedingly rare. The vast majority of pets infected with SARS-CoV-2 experience mild or no symptoms and recover fully. While deaths in animals have been reported in association with SARS-CoV-2 infection, these cases are exceptional and often involve complicating factors. The study’s findings and broader scientific consensus indicate that while pets can contract COVID-19, it is generally not a severe or fatal disease for them.
Pet owners should be reassured that the risk of their pets dying from COVID-19 is extremely low. However, practicing good hygiene, especially when sick, and consulting with a veterinarian if pets show any signs of illness remains important for responsible pet ownership. Further research will continue to refine our understanding of SARS-CoV-2 in animals and ensure the well-being of both pets and their human families.
Journal reference: Emerging Infectious Diseases, https://wwwnc.cdc.gov/eid/article/28/6/22-0423_article
