Science

Human-to-cat COVID-19 transmission affirmed in new study

Human-to-cat COVID-19 transmis...
Comprehensive case studies have confirmed human-to-cat transmission of SARS-CoV-2
Comprehensive case studies have confirmed human-to-cat transmission of SARS-CoV-2
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Comprehensive case studies have confirmed human-to-cat transmission of SARS-CoV-2
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Comprehensive case studies have confirmed human-to-cat transmission of SARS-CoV-2

A robust new study is offering the strongest clinical evidence to date of COVID-19 transmission from human to cat. The research builds on anecdotal reports from the past 12 months, but experts stress there is no evidence so far of viral transmission from domestic cats to their owners.

The research, published in the journal VetRecord, chronicles two case studies of domestic cats with respiratory illness, subsequently proven to be due to SARS-CoV-2 infection. One of the cats was ultimately euthanized due to the illness.

A comprehensive genomic analysis of the virus found in the cats suggests the animals were most likely infected by humans. The researchers found no “cat-specific mutations,” with the genomic lineages of the virus suspected to be directly connected to strains of SARS-CoV-2 spreading through humans in the UK at the time.

"These findings indicate that human-to-cat transmission of SARS-CoV-2 occurred during the COVID-19 pandemic in the UK, with the infected cats displaying mild or severe respiratory disease,” explains lead author Margaret Hosie. “Given the ability of the coronavirus to infect companion animals, it will be important to monitor for human-to-cat, cat-to-cat and cat-to-human transmission.”

Transmission of this novel coronavirus from humans to animals has been frequently reported over the past year, particularly in zoos, but this new study offers valuable evidence affirming these anecdotal observations. James Wood, from the University of Cambridge, calls this new study “important and interesting,” and says we need to closely monitor domestic pets.

“There is a growing international body of literature that is suggesting that asymptomatic transmission to pet dogs and cats from human patients may take place more commonly than disease is seen in the animals,” says Wood, who did not work on this new study. “Careful monitoring of the health of animals in contact with human patients is warranted and owners should follow advice, where possible, to try to separate themselves from their animals when they are clinically unwell.”

It is important to note, at this point there is no evidence infected domestic pets can transmit the virus back to humans. However, the concern many researchers raise is the prospect of the virus quietly spreading and mutating amongst domestic pets.

“While this paper does not look at transmission, this raises the possibility that virus variants could be more infectious for other species including cats and dogs which could possibly play a role in animal reservoirs and pose a risk of spill over back into humans,” explains Lawrence Young, from the University of Warwick.

An outbreak of infections in several mink farms across Denmark last year led to massive animal culls in the country after scientists discovered a unique mutation in the virus. This concern that the virus could quietly circulate in animal populations, developing new variants that may jump back across to humans, led to work on several vaccines custom-made for animals.

In late March, Russia approved the world’s first COVID-19 vaccine for animals. The vaccine had been tested on “dogs, cats, Arctic foxes, minks, foxes and other animals,” said the country’s agriculture ministry.

There is currently no indication domestic pets will need vaccination against the virus in the future but researchers do suggest close surveillance of the virus in animal populations will be important over the coming years.

“… it is vitally important to monitor SARS-CoV-2 infections in animals, both domesticated and free-living, as they offer a potential reservoir for virus persistence, mutation and re-emergence into the human population,” says Eleanor Riley, an infectious disease expert from the University of Edinburgh.

The new study was published in the journal VetRecord.

3 comments
3 comments
Daishi
People still think this is going to end. Many animals are likely to be asymptomatic or people may not be fully aware of their symptoms. I'm sure not many tests have been carried out at this point on animals to fully grasp the risk but this confirms the anecdotal evidence to this point. We have seen COVID mutate in mink so it's pretty safe to say that domestic pets offer potential for mutation too. Look I am not an optimist but COVID is here to stay for many reasons. In some countries they have more important things to deal with than getting people vaccinated for COVID and until the whole world is vaccinated there remains a (human) vehicle for spread and mutation. There are published research papers that offer documented proof that COVID infected mink infected some of the human workers on the mink farms (Transmission of SARS-CoV-2 on mink farms between humans and mink and back to humans). We know COVID can be spread from aerosol meaning you only need to reside within a room with an infected person even if more than 6 feet away. We know even vaccinated people will need a booster within 12 months and many people skipped even their second dose of the vaccine so we can assume many will not get the booster shot in time. We know people that have had the virus can get re-infected 6+ months later and many people with access to the vaccine refuse to vaccinate. There are already active strains in the world we suspect are not covered by the major vaccines. As a realist I can't see any objective reason to believe COVID is going away any time soon. I wish I were an optimist sometimes but from where I am sitting I think this will be the new way of life.
cafezinh062
This could explain the detection of the virus in sewage treatment plants when there are no cases in the community. Many people flush their indoor cats' poo down the toilet.
LR
I think it’s important to note that the statement about ‘no evidence cats can transmit to humans’ is basically just political - to avoid panic. There is also no evidence that cats CANT transmit to humans. It is basically unknown. Logic says the amount of air we breath into our giant lungs is much bigger than a cat so it should be harder to catch it from them, but please please do not take cats as companion animals into rest homes.