The COVID-19 pandemic has many health care professionals, including veterinarians, scrambling for answers. Questions about maintaining the safety of pets, their owners and veterinary teams desperately need expert answers as we continue trying to fulfill our role as care providers while also protecting public health.
In a webinar sponsored by Idexx Laboratories, Jane Dr. Sykes, BVSc (Hons), PhD, MBA, DACVIM, chief medical officer of the William R. Pritchard Veterinary Teaching Hospital at the University of California Davis School of Veterinary Medicine, gave a timely summary of what we know right now, and addressed vital questions about handling patients and advising pet owners.
What do we know about COVID-19 so far?
In humans, COVID-19 symptoms tend to appear after an incubation period of 2 to 14 days and include fever, myalgia, fatigue, shortness of breath, coughing, gastrointestinal signs, anosmia (impaired sense of smell) and ageusia (loss of taste). “Rarely, stroke-like neurologic signs and cardiac arrhythmias due to myocarditis have been described,” Dr. Sykes added.
The likelihood of severe illness and death increases in the elderly, as well as in people with pre-existing conditions such as diabetes mellitus, chronic lung disease or cardiovascular disease. Transmission is primarily by respiratory droplets in the form of coughing. However, transmission in pre-symptomatic people has been reported.
The virus can be detected on plastic and stainless-steel surfaces for up to 3 days, and on cardboard surfaces for up to 24 hours. However, Dr. Sykes said that the amount of viable virus diminishes during those time periods, so the chances of the organism remaining infectious for the duration are reduced.
Frequent and proper hand washing is strongly urged to help prevent transmission. “Soap and water is recommended over the use of hand sanitizer when possible,” Dr. Sykes noted. Wearing a face covering can also limit pre-symptomatic and asymptomatic transmission.
Can animals become infected?
Clinical reports
There have been a few well-reported cases of animals testing positive for SARS-CoV-2:
- In the first reported case, a 17-year-old Pomeranian whose owner was positive for SARS-CoV-2 tested ‘weak positive’ based on oral and nasal swabs. An antibody test was initially reported as negative but later reported as positive. Another dog and a cat from the same household tested negative. The Pomeranian was quarantined and remained asymptomatic but died two days after being released from quarantine. Although the owner declined a necropsy exam, clinicians suspected the dog died from complications of advanced age and pre-existing illness unrelated to COVID-19.
- Also in Hong Kong, a German shepherd that lived with a person diagnosed with COVID-19 tested positive and was quarantined. Another dog in the same household tested negative. Neither animal developed clinical signs, and the German shepherd later tested negative.
- In Belgium, samples of vomit and feces from a cat tested positive for SARS-CoV-2 after the cat developed vomiting, diarrhea and respiratory distress. The cat, whose owner had developed COVID-19 after traveling to Italy, was not examined by a veterinarian, and the owner submitted the test specimens, which has caused some to question the integrity of the diagnostic results. Dr. Sykes noted that the cat’s disease signs could have another underlying cause, and antibody testing has not been performed.
- Another cat in Hong Kong tested positive based on oral, nasal and rectal swab samples. The owner had COVID-19. The cat was quarantined but did not develop clinical signs.
- A tiger at the Bronx Zoo tested positive after exhibiting mild respiratory signs. (Several other big cats that exhibited signs of respiratory illness were not tested.) It is believed that the tiger was exposed to an asymptomatic zookeeper.
With well over 1 million human cases reported worldwide, it is noteworthy there have been relatively few reports of positive SARS-CoV-2 results in pets. Idexx laboratories reported testing over 4,000 cats, dogs, and horses (samples were taken from the United States and South Korea over a 4-week period starting in February 2020) and has yet to report any positive results. Testing has since been expanded into Europe and Canada, but so far there have been no positive results.
Dr. Sykes added that in Hong Kong, 27 dogs and 15 cats have been quarantined based on possible exposure to humans with COVID-19. So far, only the two dogs and one cat previously reported have tested positive.
Research findings
Laboratory studies are further investigating susceptibility in pets:
- Findings from a laboratory study in China suggest that cats and ferrets are more susceptible to experimental infection than dogs are. However, Dr. Sykes cautioned that because this was a laboratory study involving high-dose inoculations and young test animals, results may not reflect real-world conditions.
- In a pre-print (i.e. not yet peer reviewed) study from Wuhan, China, investigators examined neutralizing antibodies to SARS-CoV-2 in 141 pet and shelter cats in Wuhan. Researchers performed serologic testing on 39 cats before the outbreak began and 102 cats afterward. Fifteen cats (14.7%) that were tested after the outbreak began were seropositive using ELISA or virus neutralization. Investigators reported no cross-reactivity with feline coronavirus. However, all nasopharyngeal and anal swabs tested using polymerase chain reaction were negative. Exposure to COVID-19–positive humans was not established for all the cats. The researchers concluded that SARS-CoV-2 could infect cats during an outbreak in humans.
To summarize, although investigations are ongoing, available results suggest that clinical disease may occur in infected cats, but the occurrence in other species is undetermined. Further, evidence of differences in susceptibility among animal species is currently insufficient.
How should pet owners interact with their pets in a household with suspected or confirmed COVID-19?
As always, household members should wash their hands frequently and properly. COVID-19–positive humans should minimize interactions with pets, as susceptibility in pets is not fully understood. When distancing from the pet is impossible, a face covering should be worn. Pets should be quarantined at home and monitored for disease signs.
People in the household who are not suspected of having COVID-19 should try to remain separated from the infected individual, and keep pets separated as well. Dr. Sykes advised, “It’s unlikely that other people [in the home] will become infected from the pet, but it’s still recommended that they minimize pet contact, wear a face covering and, if possible, eye protection.” For the most part, she warned, “it’s the human-to-human proximity that’s the problem, not the human-to-dog proximity.”
What’s the take-home?
- SARS-CoV-2 infection in domestic animals appears to be rare.
- There is currently no evidence that animals can transmit SARS-CoV-2 to humans, either through natural infection or fomite transmission. Thus far, pet fur has not been found to act as a fomite for SARS-CoV-2 transmission to humans. Human-to-human transmission is much more likely.
- Clinical disease may occur in infected cats, but the occurrence in other species is undetermined. Evidence of differences in susceptibility among animal species is currently insufficient.
- When communicating with owners, veterinary professionals are advised to stress the importance of the human-animal bond. Contact with pets is physiologically and emotionally beneficial when humans are experiencing stress, as with the current pandemic.
- When dealing with patients and clients, veterinary staff should use appropriate precautions, such as minimizing the presence of pet owners in the facility, disinfecting pet carriers and using appropriate protective equipment when interacting with pets, particularly those from a COVID-19–positive household.
What’s the best advice for a pet owner whose pet has signs suggestive of COVID-19?
Dr. Sykes said it’s more likely that the pet is ill from something else. Pet owners who suspect COVID-19 in their pet should call their veterinarian. Some veterinary practices are offering telemedicine appointments or consults. If the pet needs to physically go to the veterinarian’s office, someone who is not sick should bring the pet. It’s also important to alert the veterinarian if a COVID-19–positive person is in the home.
What precautions should veterinary practices take with patients and clients during this crisis?
In general, the client presence in the practice should be minimized as much as possible. Implementing car-side consultations while wearing face coverings and maintaining an appropriate distance is reasonable. Collars, leashes and other pet items should not enter the practice. Pet carriers should be wiped down and disinfected before being brought into the building.
What if the pet owner is from a known or suspected COVID-19–positive household?
People diagnosed with COVID-19 should be self-quarantining at home, so another person should bring the pet to the practice. A car-side consultation is a reasonable option, with exposed staff wearing appropriate personal protective equipment (gown, gloves, face shield or goggles, N95 face mask, etc.) while maintaining physical distance as much as possible.
Dr. Sykes suggested that once a pet is removed from a pet carrier or client, the animal is unlikely to be a source of transmission. However, she advised wiping the pet down with a disinfectant wipe, minimizing the number of staff members exposed to the pet and appropriately disinfecting the exam room.
If hospitalization is needed, isolating the pet and using appropriate protective equipment during handling is recommended. Clinic staff who are in high-risk groups should not interact with these pets or clients.
Is testing of pets recommended?
PCR testing is not yet commercially available but can be obtained through veterinary research facilities. However, routine testing of pets is not currently recommended. Pets coming from COVID-19 households and exhibiting suspicious clinical signs should be tested, and testing must be done in coordination with local public health officials, following USDA guidelines.
PCR testing can be performed using swabs (nasal, rectal, oropharyngeal, hair coat). Convalescent serology may also be helpful. However, appropriate diagnostic evaluation of these pets is warranted to rule out other possible diagnoses, and protective equipment should be worn when handling these patients.
Dr. Todd-Jenkins received her VMD degree from the University of Pennsylvania School of Veterinary Medicine. She is a medical writer and has remained in clinical practice for over 20 years. She is a member of the American Medical Writers Association and One Health Initiative.
