COVID-19 and Pets: Frequently Asked Questions
Jane E. Sykes BVSc(Hons) PhD
Diplomate, American College of Veterinary Internal Medicine (Small Animal Medicine)
Chief Veterinary Medical Officer
William R. Pritchard Veterinary Medical Teaching Hospital
UC Davis School of Veterinary Medicine
Updated May 15, 2020 1552h (PST)
This document attempts to capture our current understanding of human systemic coronavirus infections as they relate to companion animals and how we might use that information to optimize the health and well-being of companion animals and their owners. The information represents the author’s personal opinions based on the available evidence and consultation with peers, and do not necessarily reflect the position of the University of California-Davis, the various members of ISCAID, or various veterinary regulatory bodies. Information on this subject is constantly evolving and readers are referred to trusted resources below for additional information and guidance. Similarly, this document is being updated by the author (sometimes multiple times a day), and readers that encounter outdated versions of this document should be aware of those limitations.
- What is a virus?
- Why can’t antibiotics be used to treat coronavirus infections?
- How are viral diseases typically transmitted?
- Can I get infected by handling objects that could be contaminated by coronavirus?
- What is a pandemic and how does it differ from an epidemic?
- Are viral diseases common in pets and what has been done to decrease the prevalence of these diseases?
- Are dogs and cats commonly susceptible to coronaviruses?
- How are coronavirus infections of dogs and cats spread, what signs do they cause, and are there vaccines for these diseases?
- What evidence is there that SARS-CoV-2 can infect dogs, cats and other animals?
- Can infected pets transmit the disease to people? Should I be taking precautions when handling dogs and cats?
- Should I (can I) test a pet for SARS-CoV-2?
- Can I still take my pet to the veterinarian if I am sick?
- How can owners prepare their pet for the Covid-19 pandemic?
Website resources for Pet Owners
A virus is a microorganism consisting of a nucleic acid in a protein coat, sometimes with a lipid envelope that surrounds this, that can infect animal cells and hijack the machinery of those cells in order to make copies of itself, or replicate. Viruses cannot multiply outside the living cells of an animal. Viruses are too small to be seen with a regular (light) microscope. In contrast, bacteria are single-celled microorganisms which have cell walls but lack organelles and an organized nucleus.
Virus infections are treated with antiviral drugs, whereas bacterial infections are treated with antibacterials (antibiotics). Antiviral drugs can be toxic because they work within an animal cell, and many only attack one type or one group of viruses. Thus there are fewer antiviral drugs than antibiotics. There are few antiviral drugs for coronaviruses, but efforts to find a cure for important coronavirus infections of animals may be key for finding a treatment for COVID-19, the disease caused by SARS-CoV2 (https://www.fox10phoenix.com/news/feline-coronavirus-treatment-could-stop-spread-of-covid-19-in-humans-doctor-says). Currently a drug called remdesivir is being used in clinical trials to treat COVID-19, which is similar to the novel drug showing efficacy in a cat disease called feline infectious peritonitis (see below)(Murphy et al, 2018; Grein et al, 2020).
In addition, the parasiticide ivermectin, widely used to treat parasitic infections of companion animals, has been shown to be active against SARS-CoV-2 in cell culture (Caly et al, 2020). Whether this will translate to an effective treatment for COVID-19 in humans remains to be demonstrated. In addition, attempts to use animal drugs to treat or prevent COVID-19 before studies have demonstrated safety and efficacy in humans are strongly discouraged because of the potential for serious side effects, including death. For example, although not yet peer-reviewed, a recent study submitted to the New England Journal of Medicine suggested that use of the drug hydroxychloroquine, proposed as an effective treatment for COVID-19, may be associated with worse outcomes than standard treatment alone. MarketWatch article). Concerns have been voiced about the use of ivermectin to treat some patients with COVID-19 (see NBC Miami article) without adequate evidence of efficacy.
There are many mechanisms through which viral diseases may be transmitted. The ability of a virus to be transmitted depends on the parts of the body it is shed from (such as saliva, feces, urine), the amount of virus shed, and how well that virus survives in the environment. SARS-CoV2 (the virus that causes COVID-19) transmission primarily occurs as a result of exposure to fine droplets expelled during coughing, sneezing, or loud vocalization (such as singing), but droplets can drift in the air for up to half an hour before settling on a surface. Transmission via touching a contaminated surface or object (i.e. a fomite) and then touching the mouth, nose, or possibly eyes is also possible. The virus is also shed in feces, so fecal contamination may also be a source of the virus (Tian et al, 2020). The duration of exposure to infected patients may also be important in the transmission of SARS-CoV-2 (Heinzerling et al, 2020).
Contaminated objects that can act as a source of transmission are referred to as fomites. Viruses that have a fragile outer lipid envelope, like the coronavirus, don’t tend to survive very long periods of time in the environment, usually hours to a few days. This contrasts with non-enveloped viruses like canine parvovirus, which can survive many months, even longer than a year, in the environment. Enveloped viruses are usually very susceptible to soap and disinfectants, when they are applied properly. A recent correspondence article published in the New England Journal of Medicine suggests that SARS-CoV2 may be capable of surviving up to 3 days on some surfaces, like plastic and stainless steel, but only up to a day on cardboard, lessening the concern about people becoming infected from deliveries. The amount of viable (alive) virus on these surfaces decreases dramatically over these periods, and the chance of people getting infected by contact with these surfaces is very low. Washing hands PROPERLY (attention to all surfaces of the hand, singing happy birthday) or properly applying hand sanitizer is the best way to prevent infection.
An epidemic is a widespread occurrence of an infectious disease in a community at a particular time. According to the WHO, a pandemic is “an epidemic occurring worldwide, or over a very wide area, crossing international boundaries and usually affecting a large number of people.” The CDC defines a pandemic as “an epidemic that has spread over several countries or continents, usually affecting a large number of people.” Thus, epidemics can be a ‘subset’ of pandemics.
Are viral diseases common in pets and what has been done to decrease the prevalence of these diseases?
There are many, many viruses that cause disease in dogs and cats. The vast majority of viruses that infect and cause disease in dogs and cats cannot infect and cause disease in humans. Examples include feline immunodeficiency virus (FIV) (which causes a disease in cats that resembles AIDS), feline leukemia virus, several different feline and canine respiratory viruses, a serious coronavirus infection of cats called feline infectious peritonitis (FIP) virus, canine distemper virus and canine parvovirus. Vaccines developed for some virus infections, such as canine parvovirus infection and distemper, when administered properly, can be completely protective. This means timing puppy and kitten vaccinations properly, using properly stored vaccines, and ensuring that puppies are kept relatively isolated until at least a week after the last (16 week) puppy vaccination. Other measures include basic hygiene (hand washing), proper disinfection and quarantine in breeding and boarding kennels, and widespread testing in order to detect the virus as well as immune populations, taking appropriate action should an outbreak of respiratory disease occur.
Coronaviruses have been known for decades to be major causes of respiratory, intestinal, or systemic infections of companion animals and livestock. They typically cause disease in very young animals, immunocompromised animals, and populations that are overcrowded or have poor nutrition and hygiene. Just like with SARS-CoV2 and humans, healthy, immune competent animals are often infected without showing any signs (animals do not experience ‘symptoms’, which are feelings of illness). Feline and canine coronaviruses are widespread among dog and cat populations. The main coronaviruses that infect dogs and cats are canine coronavirus (causing enteric or pantropic [systemic] disease), canine respiratory coronavirus, feline enteric coronavirus, and feline infectious peritonitis virus (derivative of feline enteric coronavirus). With the exception of canine respiratory coronavirus, these are alphacoronaviruses, whereas MERS, SARS-CoV, and SARS-CoV2 are betacoronaviruses. There are betacoronaviruses that infect dogs (canine respiratory coronavirus), cattle, horses and pigs. Viruses that cause the common cold in humans can be alphacoronaviruses or betacoronaviruses.
How are coronavirus infections of dogs and cats spread, what signs do they cause, and are there vaccines for these diseases?
- Canine enteric coronavirus (also known as canine coronavirus): Most cases of canine enteric coronavirus infection are contracted by oral contact with infected fecal matter that contaminates the environment, which we call fecal-oral transmission. A dog may also become infected by eating from contaminated food bowls or by direct contact with an infected dog. Typically, this virus causes mild diarrhea in puppies less than 6-8 weeks of age. There is a vaccine, but the disease is not widely recognized, and we usually start giving vaccines to puppies at 6-8 weeks of age, so it is controversial and not considered a ‘core’ vaccine for dogs. Canine enteric coronavirus can occasionally cause more severe disease, especially when it infects a dog with other gastrointestinal viruses like canine parvovirus. There have been some dogs reported worldwide (primarily in Italy) with a severe pantropic coronavirus infection, where multiple organs in the body are infected by the virus.
- Canine respiratory coronavirus: Canine respiratory coronavirus is transmitted the same way that SARS-CoV2 is transmitted, through respiratory droplet inhalation and fomite spread in crowded environments such as boarding kennels. It is one of the many (MANY) causes of canine infectious respiratory disease complex (also known as ‘kennel cough’). Interestingly, this virus was first identified in the United Kingdom in boarding kennels and subsequently spread rapidly worldwide and is more closely related to a bovine coronavirus and one of the coronaviruses that causes the common cold in humans, known as OC43. There is no vaccine for this infection, but vaccines exist for other causes of CIRDC, like Bordetella and canine parainfluenza virus.
- The virus that causes FIP is transmitted through the fecal-oral mechanism but is unique in that the virus that is spread, feline enteric coronavirus, is only capable of causing mild diarrhea. In a small proportion of infected cats, the enteric coronavirus can mutate to a nasty or virulent virus that we call FIP virus. The new virus is capable of spreading throughout immune cells in the body and causing the fatal disease, FIP. That virus is not shed from the body and does not infect other cats through cat to cat contact. FIP virus causes fever primarily in young adult cats, weight loss, and signs that relate to the primary organs affected. There are two forms of the disease, commonly known as the ‘dry’ and ‘wet’ forms. In the ‘dry’ form, there is inflammation in several organs. Involvement of the brain leads to neurologic signs like seizures, the lungs respiratory signs like trouble breathing, the liver jaundice, and the eyes uveitis, which manifests as a cloudy or discolored eye. In the ‘wet’ form, there is fluid accumulation in the chest, with breathing problems; fluid accumulation in the abdomen leads to abdominal enlargement. There is an intranasal vaccine for this disease, but its efficacy is controversial, and it is licensed for administration after most cats get infected with the enteric coronavirus. Dr. Niels Pedersen at UC Davis has spent most of his career researching this disease and has recently identified an antiviral drug, GS-441524, that shows tremendous promise for treating this disease.(1) Unfortunately, the drug is not commercially available and desperate owners have turned to the black market to obtain it.
- What evidence is there that SARS-CoV-2 can infect dogs, cats and other animals?
Historically, there has been evidence of transmission of human respiratory viruses to dogs and cats. For example, the 2009 pandemic H1N1 influenza virus spread to a dog in New York, which developed respiratory signs, and several cats and ferrets became infected, developed respiratory signs and some even died as a result of the infection. While transmission back to humans was not clearly documented for H1N1, in 2016, an H7N2 influenza outbreak occurred in a New York municipal animal shelter in cats and there was some evidence of transmission back to 2 of the 121 workers in the shelter. Typically, these influenza outbreaks that spill over to dogs and cats quickly die out and ongoing transmission is not maintained.
SARS-CoV, which appeared in 2003, was thought to have spread likely from bats to civet cats — small mammals that resemble weasels — before the first human patient was infected. Civet cats are not cats but more closely related to mongoose. However, during the SARS outbreak in Hong Kong in 2003, a small number of pet cats tested positive for the virus, but none became sick and there was no evidence of natural spread from one cat to another. These pet cats were housed in the Amoy Gardens apartment complex where an unusual outbreak of infection occurred in humans that appeared to be related to airborne transmission that was related to the sewerage drainage system within the highrise complex (McKinney et al, 2006). Ferrets could also get infected and develop illness (lethargy), but experimentally infected cats did not show signs of illness (Lun et al, 2004; Martina et al, 2003). Although these animals were able to transmit infection to in-contact animals experimentally (Lun et al, 2004), there has been no evidence of natural viral transmission from pet dogs, cats, or ferrets to humans reported.
MERS (Middle Eastern Respiratory Syndrome) coronavirus appeared to originate in dromedary camels and spread to humans. It appeared in 2012 in Saudi Arabia, and subsequently spread to other countries, including a few cases reported in the United States in 2014. There was no evidence of spread of this virus to dogs and cats.
In late February and March of this year, oral and nasal samples were collected from an apparently healthy 17-year old Pomeranian (‘Benny’) in Hong Kong that lived with a person infected with SARS-CoV2 (the novel coronavirus that causes COVID-19). The samples tested weakly positive for the virus. The dog was quarantined, and subsequently, additional nasal and oral samples collected during the course of quarantine also tested weakly positive. This suggested that the dog may be infected, rather than just contaminated with the virus. It is important to note that viable (‘alive’) SARS-CoV2 was not grown from the dog in Hong Kong – only RNA was identified via RT-PCR. Another dog and a cat from the same household tested negative. Subsequently, an antibody test was done on a blood sample from the dog (collected on March 3, 2020), which initially was reported as negative, suggesting that the dog had not become infected, although there can be reasons for false negatives.
Two days after the Pomeranian was released from quarantine (March 17, 2020), it died suddenly. Unfortunately, the owner declined a postmortem. However, because it was a 17-year old dog with advanced cardiac disease that showed no other signs during quarantine, there is a high likelihood that death was unrelated to coronavirus infection. On March 19, 2020, we heard that further serological testing done on the blood sample collected from the Pomeranian in early March showed that it was actually positive, suggesting that the dog had mounted an immune response to the virus. On the 26th of March, a spokesperson from the Hong Kong Agriculture, Fisheries and Conservation Department (AFCD) confirmed that a positive result had been obtained at the World Health Organization reference laboratory at the University of Hong Kong and the dog had been infected by the virus.
On March 19, 2020, it was also announced that a second dog in Hong Kong, a 2-year old German Shepherd that lived with a person diagnosed with COVID-19, had tested positive for the virus (nasal, oral and rectal swabs). The dog was quarantined, in addition to a 4-year old dog from the same household, which tested negative. Samples were positive on three consecutive days of quarantine, after which subsequent samples tested negative. On April 8, the OIE reported that SARS-CoV-2 had been isolated in cell culture from this dog on March 23, and the dog was seropositive using virus neutralization on April 3, 2020. Neither of the dogs have shown signs of disease (COVID-19), and none of the staff handling the dogs during quarantine have been reported to develop COVID-19.
On March 27, 2020 reports emerged from veterinary faculty at the University of Liege and the Veterinary Services of Belgium that samples of vomit and feces from cat in Belgium had tested positive for SARS-CoV2 using PCR (see ProMed Mail Report). The cat lived with a woman who had been diagnosed with COVID-19 after returning from Italy. In addition, the cats started showing clinical signs suggestive of COVID-19 a week after the owner developed signs, and the signs consisted of vomiting, diarrhea, and respiratory distress. The cat was not examined by a veterinarian and the owner collected the samples. It was reported that a significant virus load (CT value 22) was detected in the samples. The detection of a significant quantity of SARS-CoV2 RNA in feces and vomit from the cat in Belgium suggests that cats can become infected with this virus, but caution is advised as the test details have not been fully described. We still don’t have antibody tests back on this cat but it was reported that testing would be done when the cat is released from quarantine. While the cat’s clinical signs were suggestive of disease caused by the coronavirus, there are other causes of such signs and the positive tests do not prove that the cat’s signs were caused by the virus. Should a positive antibody test be identified once the cat has had time to mount an immune response, this would strongly support natural infection.
It is not particularly surprising to hear of infected cats and dogs based on what we know about their receptors for the virus and their ability to be infected with the 2003 SARS-CoV. SARS-CoV2 utilizes two receptors to enter human cells: the Angiotensin-Converting Enzyme 2 (ACE2) receptor and a type-II transmembrane serine protease (TMPRSS2) (Hoffmann et al, 2020) (this is similar to the original SARS virus in the early 2000s). It appears that the overall homology of human ACE2 receptors are similar to cat and dog ACE2 receptors (approximately 90%)(Lie et al, 2012; Luan et al, 2020; Qiu et al, 2020). In one study, there appeared to be slightly more similarity between cat ACE2 receptors and human receptors when compared with dog ACE2 receptors and human receptors, although the ‘dog’ sequence used for comparison was that from a dingo.(Wan et al, 2020) In another study, a critical virus binding site of ACE2 receptors in cats, dogs and ferrets (amino acid sequence KEETK) was reasonably similar to those of humans (KEDMK, differing by two amino acids), so it was predicted that SARS-CoV2 binds to ACE2 receptors in cats, dogs and ferrets (Luan et al, 2020).
In addition, a study from China showed that cats and ferrets were more susceptible to experimental infection with SARS-CoV-2 than dogs, and that cats and ferrets could transmit infection to other cats and ferrets, whereas dogs did not transmit infection to a small number of in contact dogs (Shi et al, 2020). Younger cats (70-100 days) were reportedly more susceptible than older (8-month old) cats, and although these younger cats were reported to have pathological changes in their upper and lower respiratory tract at necropsy after death or euthanasia, the researchers stated later in a Nature news report that none of the cats showed signs.
On April 2, a pre-print was released that described a serosurvey of a random-source domestic cat population in Wuhan, China. The researchers performed serological testing on serum from 39 cats before the outbreak and 102 cats sampled after the outbreak. Of the 102 cats sampled after the outbreak, 15 (14.7%) were positive. Nasopharyngeal and anal swabs all tested negative using PCR. The cats were from shelters and other sources and the extent of their contact with people with COVID-19 was not reported. The researchers also stated that there was no cross-reactivity of their assay with feline coronavirus. This remains a non-peer reviewed publication at this time and similar findings have not yet been described by other researchers.
On April 3, 2020, a cat in Hong Kong was reported to be subclinically infected with SARS-CoV2. The owner had COVID-19 and the cat was quarantined on March 30. Nasal, oral and rectal swab specimens tested positive and follow up samples on April 1 were also positive.
As of 8 Apr 2020, the Hong Kong Agriculture, Fisheries and Conservation Department (AFCD) had conducted tests on 33 dogs, 17 cats and 2 hamsters quarantined from households with confirmed COVID-19 cases or persons in close contact with confirmed patients, and only the 2 dogs and the cat had tested positive for the COVID-19 virus. None of the animals had clinical signs of disease. (See also earlier ProMed Mail report). On May 14, a paper was published in Nature that described the findings in positive dogs (Sit et al, 2020).
On April 5, 2020, a report was released of an infected Malayan tiger at the Bronx zoo in New York. The tiger was tested because it developed a dry cough and inappetence on March 27 and was in contact with a caretaker that was subclinically (presymptomatically) shedding SARS-CoV2. In addition, the tiger’s sister, 2 Amur tigers and 3 African lions at the zoo were reported to develop similar signs by April 3, 2020. These cats then also tested positive. How transmission occurred among the cats was not clear, but it was presumed that all the cats had been infected from the caretaker.
On April 18, a ProMed Mail report described positive SARS-CoV-2 tests in two cats from New York. Infection was confirmed following retesting at National Veterinary Services Laboratories on April 22, in a release from the CDC. The release stated that both cats had mild respiratory signs and were from two separate households. One had no known contact with infected humans, and was presumed to have been infected through asymptomatic transmission or someone outside the household. The other came from a household with a person that had recently been diagnosed with COVID-19. The other cat in the household was showing no signs. Subsequently it was reported that the two cats also seroconverted.
On April 7, 2020, a press release of another experimental infection study was made from Germany that demonstrated the susceptibility of ferrets and fruit bats to infection. Pigs and chickens were not susceptible to infection.
On April 9, 2020, a preprint was released that described a lack of evidence of infection or exposure in 9 cats and 12 dogs that were living with a group of veterinary students in France, 2 of which had been confirmed to have COVID-19 and 11 with respiratory disease that was suspicious for COVID-19 but not confirmed. Peer review of this manuscript has not been completed, and it was unclear exactly the degree of contact between animals and truly infected people.
In addition, one major veterinary diagnostic laboratory, IDEXX, made a statement that they have now tested more than 5000 samples from dogs, cats and horses using PCR and no evidence of the coronavirus was found, although these have been stored samples and it is unclear to what extent the animals had been exposed to infected people. Specimen collection started on February 14, 2020. Initially specimens were collected from animals in South Korea and the US, including impacted areas like Seattle, and then from mid-March, testing was expanded to impacted areas in Canada and EU countries.. The results have been confirmed using three assays run in parallel from the CDC.
An article in the journal Molecular Biology and Evolution from a researcher in Ottawa, Canada hypothesized that stray dogs, through consumption of bats, may have been responsible for transmission of SARS-CoV-2 to humans. This was based purely on the finding of a markedly low levels of CG dinucleotides in SARS-CoV-2, with the next closest coronavirus studied being a single canine coronavirus strain, together with the suggestion that the dog as a host must have selected for the low CG dinucleotide composition. While an interesting similarity, it could just as easily be a coincidence.
Most recently, a preprint was released by researchers in California that described ACE2 receptor composition of 410 vertebrates, including over 250 mammals. Analysis of twenty-five amino acid residues that contributed to critical binding sites for SARS-CoV-2 suggested that domestic cats might be intermediate in susceptibility whereas dogs might be low; what did not align with results of experimental infections so far was that ferrets were predicted to be of low susceptibility.
Given the low numbers of dogs and cats reported to be infected in the field, it still has not been possible to say whether cats are truly more susceptible to infection or clinical signs of disease.
On April 26, 2020, it was reported that mink on two farms in the Netherlands had tested positive for SARS-CoV-2 after an increased mortality rate was noted along with signs of respiratory distress and gastrointestinal signs. The farms had over 20,000 mink among them and represented two of more than 100 farms remaining after the government placed a ban on fur farming in 2013. Workers on the farm were reported to have signs of respiratory illness and were suspected as the source of infection for the mink. Like ferrets, mink belong to the family Mustelidae, and given the susceptibility of ferrets to experimental infection, it is not surprising that mink were found to be susceptible. On May 7, two additional farms were reported to be positive (ProMed Mail, Vol 94, Issue 36), and on May 15, it was reported that a total of 5 farms had been affected.
On April 28, it was reported that a pug, Winston, in North Carolina was infected with SARS-CoV-2 and had signs of cough/gagging and decreased appetite. The infection was recognized because the family were part of a study at Duke University and were being tested as part of surveillance efforts. The owners had mild symptoms of COVID-19. One other dog and a cat in the household tested negative.
On April 30, a ProMed Mail report described identification of a PCR-positive cat in Paris as part of surveillance efforts. According to the report, rectal and nasopharyngeal swabs were being collected from cats that were in contact with people with COVID-19, and a rectal swab from one cat had tested positive. The total number of cats tested was not stated in the report.
On May 8, there was a report of an infected Maine Coon cat from Catalonia in Spain (‘Nigrito’). The cat was euthanized because of what were described as severe respiratory signs, but these were secondary to congestive heart failure. The cat tested weakly positive on nasal and gastrointestinal samples collected at necropsy and had been in contact with someone with COVID-19.
On May 13, ProMed Mail (Vol 94, Issue 40) described a 6-year old cat that tested positive for SARS-CoV2 that was in contact with people with COVID-19 in a retirement home in Bavaria. Two other cats in the household (15 yo and 10 yo) tested negative. None of the cats were ill. The cats were isolated in separated facilities. A second positive cat in Bordeaux, France was also reported. That cat had respiratory signs but whether they were related to the positive test result was not clear.
Also on May 13 came a publication (correspondance) in the New England Journal of Medicine that described experimental infection of three cats with SARS-CoV-2 (Halfmann et al, 2020). Each of the cats were then co-housed with a cat that was uninfected, and transmission to all of the in-contact cats occurred; the cats shed virus for about 4-5 days and seroconverted with very high titers to the virus. No cats developed clinical signs and virus was only detected in nasal and not rectal swabs.
On May 15 there was a report of an seropositive bulldog from a household in the Netherlands with COVID-19. The bulldog had been euthanized with severe respiratory disease and had seroconverted to the virus, but tested negative using PCR. It is not yet clear whether the bulldog’s signs were related to the viral infection. In addition, three of 11 farm cats that roamed on one of the mink farms with SARS-CoV-2 infection in the Netherlands were also reported to have tested antibody positive, PCR-negative (source, NL Times).
Can infected pets transmit the disease to people? Should I be taking precautions when handling dogs and cats?
Currently, we don’t have any evidence that dogs and cats, and even ferrets, can transmit SARS-CoV2 to humans outside the laboratory, either as fomites or as virus shedders. To date, all transmission has been human-to-human, after the initial jump from bats (most likely) to humans. After the report of the infected cat, the World Organization for Animal Health (OIE) updated their site to say that although some examples of animal infections have been reported to the OIE, currently there is ‘no evidence to suggest that animals infected by humans are playing a role in the spread of COVID-19. Human outbreaks are driven by person-to-person contact.’ Similarly, the World Health Organization has acknowledged that although there are instances of animals and pets being infected with SARS-CoV-2, human to human transmission remains the main driver.
Although dogs and cats ‘in the field’ can shed the virus, it remains unclear if they can transmit it to humans, especially if there are no signs of respiratory disease to create air-borne droplets for transmission.
Since other infectious diseases can spread between animals and humans (diseases spread from animals to humans are called zoonoses), it is prudent to always exercise good hygiene when people, especially children and the immunocompromised, are around animals. This includes washing your hands (properly) after touching, feeding or cleaning up after your pet, avoiding rough play (especially between children and animals), and not allowing pets to sleep in the bed with immunocompromised people or lick faces, wounds or healthcare devices.
If pet owners are known to have COVID-19 (i.e. through testing), or highly suspected to have it and are unable to get tested, additional special precautions are warranted. In that case, they should limit contact (ideally have someone else in the household take care of the pet) and wear a face mask. Their pet should be quarantined with them and any signs of illness in their pet should be reported to their veterinarian.
Critically, it is important that pet owners not over-react and disconnect from their pet. The importance of the human-animal bond and its positive healthcare effects cannot be overestimated. There is evidence that pet ownership has many health benefits, including reduction in mental illness and cardiovascular disease, decreased blood pressure and improved self-esteem in children. Owners should not panic about the possibility of pet infection and transmission, and instead enjoy all the positive healthcare benefits of the bond they have with their pets. On the one hand, restriction of human movement may reduce adoption of pets from shelters, and more animals in need of homes may be euthanized as a result; on the other hand, we have also been aware of an increase in fostering animals by those looking for companionship during the quarantine period. This is great news, but some people have raised concerns that these animals will not receive adequate long-term care or be abandoned when quarantine is relaxed.
Many animal diagnostic laboratories are not currently set up to test for this specific coronavirus. Recently, IDEXX Laboratories announced they are offering animal testing for SARS-CoV-2.
In the case of the Belgian cat, the owner collected samples for testing and the animal remained in quarantine with the owner. In the United States, any testing should be overseen by local public health officials. The USDA states that ‘at this time, testing for companion animals will only be done if animal and public health officials agree testing should occur due to a link to a known human case of COVID-19. We will not be testing the general companion animal population. After the decision is made to test, the state animal health officials will designate a state-appointed veterinarian, USDA accredited veterinarian, or Foreign Animal Disease Diagnostician (FADD) to collect the sample using appropriate personal protective equipment and sample collection methods. State animal health laboratories can/will conduct animal testing, but any positive samples would need to be confirmed through additional testing by USDA’s National Veterinary Services Laboratory’. In addition, the CDC has released guidelines for the testing of animals for SARS-CoV-2.
Veterinarians must contact state animal health officials for direction if an infected owner contacts them and requests testing of their pet should it develop signs of respiratory or gastrointestinal illness after known exposure to an infected human. The California Department of Public Health has recently released guidelines for veterinarians about the handling of animals from positive households. In these guidelines, it is recommended that veterinarians wear an N95 face mask, eye protection, gown and gloves when interacting with people from COVID+ households. However, many veterinary clinics are not set up for this level of protection – N95 masks must be fitted and fit-testing is not widely available at this time. Once the animal is removed from the client, full PPE (N95 masks, eye protection, gown) is not considered indicated by public health officials at the time of writing, but given the lack of evidence either way, veterinary clinics could consider wearing PPE when handling possibly infected animals.
Owners should be aware that should their dog or cat develop respiratory illness, that respiratory illness (‘kennel cough’ and ‘cat flu’) is extremely common in dogs and cats, especially those that board, go to ‘doggy daycare’ or are acquired from shelter environments. There are more than 10 different viruses and bacteria that can cause these signs in dogs, including canine respiratory coronavirus, which only infects dogs. Any pet that develops respiratory illness is much, much, MUCH more likely to be infected with a dog or cat respiratory virus or bacteria (including coronaviruses that only infect dogs, such as canine respiratory coronavirus) than the novel coronavirus. These dog and cat viruses do not cause infections in people. Pet owners should be told to have their pet evaluated by a veterinarian if signs of runny nose/eyes, cough, or sneezing develop, and not allow their pet to contact other animals in the meantime. Veterinarians should be vigilant about the possibility of infections in animals in contact with people that have COVID-19. Animals with possible COVID-19 should first be assessed on a video call to determine whether they need to leave the home environment for veterinary care. If treatment at a hospital location is indicated, then animals should be housed in isolation and handled by a limited number of trained individuals with full PPE.
Self-quarantine is recommended if pet owners are sick. If an animal is sick and needs veterinary attention, owners should call them and tell them that they have or may have COVID-19. This will help the veterinarian’s office take steps to keep other people from getting infected or exposed. If possible, someone else from the household can take the pet in using suitable precautions as recommended by the veterinarian. A telemedicine appointment may be possible beforehand if the pet has been seen by the veterinarian in the last year (i.e. a valid veterinarian-client-patient-relationship [VCPR] exists; some states are relaxing the need for a VCPR in light of the outbreak, so owners should check with their veterinarian about the possibility of a telemedicine consultation).
If owners are not sick, veterinarians are considered essential health services and are still offering, at the minimum, emergency care. Owners should call their veterinarian and ask them whether they have a protocol for interacting with clients and patients during this period of physical distancing. The owner and veterinarian can discuss the safest approach for all concerned whether the animal needs immediate medical intervention or not. Prescriptions can be mailed, and as noted above, many veterinarians are providing video consultations occur over platforms like Zoom or platforms especially designed for telemedicine purposes. If a VCPR is required, these can be suitable for recheck examinations, especially when a detailed physical examination is not necessary.
On April 22, the CDC released guidance for veterinary clinic operations on their website, which align with recommendations from the AVMA and ISCAID. This was updated on May 12.
- Owners that have not had COVID-19 should prepare their pets, just as they prepare their family, for possible future quarantine. This includes stocking up on a 2-4 week supply of food, medications (don’t forget prescription medications), litter and other supplies. (The CDC offers additional information)
- Owners should make sure their pets’ medical records, vaccines, and preventative medications (tick, flea, internal parasites) are up to date in the event they cannot care for them and need to board their pet.
- Owners should practice good hygiene during interactions with their pet (e.g., wash hands before and after interacting with their pet; ensure their pet is kept well-groomed and is bathed on a weekly basis; regularly clean their pet’s food and water bowls, bedding material, and toys).
- If owners are not ill with COVID-19, they can interact with their pet as they normally would, including walking, feeding, and playing.
- Owners should wash their hands before and after any contact with their pet or service animal. They should not share dishes, drinking glasses, cups, eating utensils, towels, or bedding with other people or pets in their home.
As Chief Veterinary Medical Officer, Dr. Sykes oversees all clinical and support services of the William R. Pritchard Veterinary Medical Teaching Hospital at the UC Davis School of Veterinary Medicine, one of the largest and most comprehensive veterinary medical centers in the world. A UC Davis faculty member since 2002, she previously served as Director of the hospital’s Small Animal Clinic, Chief of the hospital’s Small Animal Internal Medicine Service, and Biosecurity Officer of the hospital’s Small Animal Clinic. She has special expertise in infectious diseases of dogs and cats. Dr. Sykes received her veterinary degree and a PhD in veterinary microbiology from the University of Melbourne (Melbourne, Australia). She completed her residency in small animal internal medicine at the University of Minnesota and served as a clinical faculty member there before coming to UC Davis.
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UC Davis Veterinary Medical Teaching Hospital
UC Davis Veterinary-related coronavirus resources
Veterinary Information Network (VIN) FAQ on COVID-19 for pet owners
World Organization for Animal Health (OIE)
Questions and answers on the 2019 coronavirus disease
U.S. Centers for Disease Control and Prevention (CDC)
Coronavirus disease 2019: Frequently asked questions and answers
World Health Organization (WHO)
American Veterinary Medical Association (AVMA)
IDEXX COVID-19 Customer Resources