Saturday, March 20, 2021

COVID Variant B.1.1.7 & Companion Animals



Although COVID-19 has become (in just over a year) predominantly a disease in humans it is believed to have originated in bats, and then jumped - either directly or via an intermediate host - to humans. Exactly how and where that occurred has yet to be determined. 

While we've seen scattered reports of cats (big and small), and a few dogs infected with SARS-CoV-2 (see Seroprevalence of SARS-CoV-2 in Dogs & Cats - Italy), the biggest affected non-human species to date has been farmed mink (a close relative of ferrets).

Initial studies, conducted in the spring of 2020 (see  Susceptibility of Ferrets, Cats, Dogs & Other Domestic Animals to SARS-CoV-2),  found that `. . . SARS-CoV-2 replicates poorly in dogs, pigs, chickens, and ducks, but efficiently in ferrets and cats. We found that the virus transmits in cats via respiratory droplets.'

While relatively good news on the livestock front, the ability for companion animals like dogs and cats to become infected has raised concerns.  More recent studies (see EID Journal: Susceptibility of Domestic Swine to Experimental Infection with SARS-CoV-2) suggest livestock may be a bit more susceptible to SARS-CoV-2 infection that previously believed. 

The CDC's COVID-19 and Animals webpage, updated Feb. 10, 2021

What you need to know
  • We do not know the exact source of the current outbreak of coronavirus disease 2019 (COVID-19), but we know that it originally came from an animal, likely a bat.
  • At this time, there is no evidence that animals play a significant role in spreading SARS-CoV-2, the virus that causes COVID-19, to people.
  • Based on the limited information available to date, the risk of animals spreading COVID-19 to people is considered to be low.
  • More studies are needed to understand if and how different animals could be affected by COVID-19.
  • We are still learning about this virus, but it appears that it can spread from people to animals in some situations.
  • People with suspected or confirmed COVID-19 should avoid contact with animals, including pets, livestock, and wildlife.

The caveat to all of this is, most of what we know is based on the `wild type' SARS-CoV-2 virus, and no one is quite sure how the rise of new variants will affect the status quo.  While their impact may very well be negligible, the B.1.1.7 variant has already been demonstrated to be more transmissible - and more severe - in humans. 

Since these variants are relatively new on the scene and continue to evolve, it remains to be seen what impact - if any - they will have on non-human hosts. 

But this week we have two reports - one from the UK and the other from the United States - on infection of companion animals by the B.1.1.7 variant.  The first comes from Texas A&M University, which released the following statement on Monday.

Texas A&M Research Uncovers First Known COVID-19 UK Variant In Animals

The variant was detected in a dog and cat in Brazos County.

By Jennifer Gauntt, Texas A&M University College of Veterinary Medicine & Biomedical 

MARCH 15, 2021

The United Kingdom variant (B.1.1.7) of SARS-CoV-2, the virus that causes COVID-19, has been detected for the first time in a dog and a cat from the same household in Brazos County, Texas, as part of a study led by researchers at Texas A&M University.

The first reported finding of the B.1.1.7 human variant virus in any animal worldwide, this detection of the UK variant in animals in a natural household setting reinforces the importance of having procedures in place to monitor the SARS-CoV-2 viral genome as it crosses species barriers, giving specialists both insight and time to study potential new variants before they spread through animal or human populations.

“Surveillance of SARS-CoV-2 in animals in and around households and genetic investigations of the virus from infected pets are critically important for understanding the transmission and evolution of the virus as well as predicting what may happen next,” said Dr. Sarah Hamer, a veterinarian and epidemiologist in the Texas A&M College of Veterinary Medicine & Biomedical Sciences (CVMBS) who serves as principal investigator for the COVID-19 & Pets study that uncovered the variant.

The B.1.1.7 variant was confirmed in both pets, a senior black lab-mix dog and a senior domestic shorthair cat, from the household where the owner was diagnosed with COVID-19 in mid-February.

The pets were tested on Feb. 12, only two days after their owner was diagnosed with COVID-19, as part of an ongoing research project, funded by the Centers for Disease Control and Prevention (CDC), which is being conducted by researchers in Texas A&M’s CVMBS, College of Agriculture and Life Sciences (COALS), and School of Public Health.

Neither animal showed any overt sign of illness at the time of their positive tests.

Whole genome sequencing results from the respiratory swabs collected from the animals last month were completed March 12 at the U.S. Department of Agriculture’s (USDA) National Veterinary Services Laboratories (NVSL) and showed the dog and cat had identical sequences of the B.1.1.7 variant.

These companion animals were retested March 11, at which time the owner disclosed that the dog and cat had both been sneezing over the past weeks; the owner is now reporting that both are in good health.

The investigation into SARS-CoV-2 infections in people and pets in this household is ongoing.

While this establishes the susceptibility of dogs and cats to the B.1.1.7 variant, the good news is neither animal showed overt signs of illness at the time of their testing positive.

Slightly less reassuring is a preprint article - published on Thursday in BioRxiv - that documents myocarditis in B.1.1.7 infected pets in the UK.  As always, the caveat applies that this is not a peer-reviewed study.

The authors report an abrupt increase (1.4% to 12.8%) in domestic dogs and cats presenting with myocarditis at a large veterinary clinic on the outskirts of London between December 2020 and February 2021, a timespan which corresponds with  the rise of COVID B.1.1.7 in the UK. 

While there appears to be a correlation between the B.1.1.7 variant and these cases of myocarditis, causality has yet to be proven.   It is, however, an interesting finding. 

Below you'll find the link, abstract, and an excerpt from the study.  Follow the link to read it in its entirety. 

Myocarditis in naturally infected pets with the British variant of COVID-19
Luca Ferasin, Matthieu Fritz,  Heidi Ferasin,  Pierre Becquart,  Vincent Legros,  Eric M. Leroy
This article is a preprint and has not been certified by peer review [what does this mean?].
Preview PDF

Domestic pets can contract SARS-CoV-2 infection but, based on the limited information available to date, it is unknown whether the new British B.1.1.7 variant can more easily infect certain animal species or increase the possibility of human-to-animal transmission. In this study, we report the first cases of infection of domestic cats and dogs by the British B.1.1.7 variant of SARS-CoV-2 diagnosed at a specialist veterinary hospital in the South-East of England. 

Furthermore, we discovered that many owners and handlers of these pets had developed Covid-19 respiratory symptoms 3-6 weeks before their pets became ill and had also tested PCR positive for Covid-19.

 Interestingly, all these B.1.1.7 infected pets developed atypical clinical manifestations, including severe cardiac abnormalities secondary to myocarditis and a profound impairment of the general health status of the patient but without any primary respiratory signs. 

Together, our findings demonstrate for the first time the ability for companion animals to be infected by the B.1.1.7 variant of SARS-CoV-2 and raise questions regarding its pathogenicity in these animals. Moreover, given the enhanced infectivity and transmissibility of B.1.1.7 variant for humans, these findings also highlights more than ever the risk that companion animals may potentially play a significant role in SARS-CoV-2 outbreak dynamics than previously appreciated.

To our knowledge, this is the first report of infection of both cats and dogs by the British B.1.1.7  variant of SARS-CoV-2. Given the enhanced infectivity and transmissibility of B.1.1.7 variant for humans, the discovery of B.1.1.7 infected cats and dogs highlights more than ever the risk that companion animals may potentially play a significant role in SARS-CoV-2 outbreak dynamics than  previously appreciated.

 Further studies are therefore urgently required to investigate the likelihood of pet-to-pet transmission, as well as pet-to-human transmission of the B.1.1.7 variant and to show whether the N501Y mutation and the Δ69-70 deletion render the virus more infectious for these  animals. 

 The other remarkable and unexpected finding of our study is the development of unusual clinical  manifestations in B.1.1.7 infected cats and dogs, including severe cardiac abnormalities secondary to  myocarditis and a profound impairment of the general health status of the patient but without any  primary respiratory signs.

With the exception of only one cat from Spain, which developed cardiorespiratory failure resulting in severe respiratory distress , both natural and experimental SARS150 CoV-2 infections of cats and dogs have so far been reported to be either asymptomatic or display mild upper respiratory disease.

Although that the B.1.1.7 infection in humans seems to be associated with higher COVID-19 mortality or clinical severity, the association between myocarditis and B.1.1.7 infection in domestic pets has to be acknowledged and addressed  . In this context, it is important to highlight the fact that myocarditis associated with multisystem inflammatory syndrome is also a well recognized complication of COVID-19 in people (both adults and children) probably from exaggerated immune response of the host . 

Together, our findings demonstrate the ability for companion animals to be infected by the B.1.1.7  variant of SARS-CoV-2 and raise questions regarding its pathogenicity in these animals. Therefore,  there is an urgent need to greatly accelerate and strengthen the investigations and surveillance of  animal infections by highly-transmissible variants such as British B.1.1.7, South-African B1.351 and  Brazilian P.1 variants as part of the global response to the ongoing multi-species COVID-19  pandemic. 

With respect to companion animals, you and your family pose a bigger threat of infecting your dog or cat, than they do of infecting you.  The virus is already rife in the human population, and so pets are unlikely to play a major role in spreading the virus. 

The bigger risk comes if SARS-CoV-2 becomes endemic in a farmed species, like pigs or cattle  (both of which are susceptible to other coronaviruses), or other peri-domestic mammals (like skunks, raccoons, rodents, and rabbits). 

Just over a month ago, in EID Journal: SARS-CoV-2 Exposure in Escaped Mink, Utah, USA,  we looked at a report on the investigation into the possible spillover of the virus from Utah farms into local wildlife that was both reassuring and concerning at the same time.

Reassuring because there was no evidence of the establishment of SARS-CoV-2 in nearby wildlife, but concerning because 11 presumed `escaped' mink, living near the farms, tested positive for SARS-CoV-2 antibodies.
Meaning there were opportunities for a spillover into wildlife to occur, even though none appeared to have taken hold in this instance. 

While the news regarding the susceptibility of farmed livestock to SARS-COV-2 has been generally reassuring, the potential for more spillovers can't be ignored, particularly as new variants emerge.