I seriously considered this as my email auto-reply today:
- Thanks for your email. Yes, I’m aware of that new canine/human coronavirus paper that was released today. I’m in a symposium all day and have only skimmed the paper. I’ll read it later tonight and presumably blog about it.
- PS: This isn’t the next COVID-19. Relax.
I actually got a chance to carefully read the paper, published in Clinical Infectious Diseases (Vlasova et al. 2021), and here are some of my thoughts, as promised…
The paper describes an interesting preliminary study that found a new coronavirus in a small number of hospitalized patients with pneumonia in Malaysia. Analysis of the viral genetics was consistent with it having originated from a canine coronavirus.
To back it up a bit, there are lots of coronaviruses out there in lots of different species that we deal with all the time. Animals are likely the origin of most or all of our coronaviruses, ranging from SARS-CoV-2 to the coronaviruses that cause the common cold. Some of these jumped to people very recently. Some probably hundreds of years ago.
A few different coronaviruses are known to infect dogs. The one I pay the most attention to clinically is canine respiratory coronavirus, a betacoronavirus that’s increasingly recognized as an important cause of respiratory disease in dogs. That’s NOT the virus they’re talking about in this study. The dog virus the authors discuss in this study is an alphacoronavirus called canine coronavirus (CCoV), of which there are a couple types.
Back to the study:
- In swabs from 301 people hospitalized with pneumonia, they found PCR evidence of CCoV in 8 patients. A live coronavirus was cultured from one of those samples.
- When they looked at the genetic makeup of the virus, it was most closely related to CCoV and therefore named CCoV-HuPn-2018 (canine coronavirus-human pneumonia-isolated in 2018).
- It’s a new strain within the Alphacoronavirus 1 species. It is suspected to have evolved as a result of multiple different recombination events (viruses swapping RNA) between different Alphacoronavirus 1 strains.
- Some genetic changes might have increased its affinity for people compared to regular CCoV. How well it can infect people and whether people can transmit it (to other people or dogs) isn’t clear.
Is this surprising?
Yes and no. A new recombinant virus is always noteworthy, but this is what viruses do, and why we always have to pay attention to zoonotic disease risks.
Is it concerning?
Not really. It’s not clear that the virus actually caused disease. Other respiratory viruses were found in 7 of the 8 positive patients, including the person from whom the virus was cultured. That person also had influenza. So, it’s hard to say if the virus was just there doing nothing, if it’s a rare cause of disease, if it’s an established but previously undetected cause of human infections, or something else.
Also, there was no evidence of human-to-human transmission. It’s impossible to say whether that was occurring – presumably it was (versus repeated spillover events into multiple individuals from animals harbouring this virus) but who knows. The key is there wasn’t a concerning disease pattern.
One more thing: the study was based on samples from 2017-2018. Clearly nothing big has happened in the interim.(Well, you know what I mean. Nothing big with this virus.)
Take home message
New coronaviruses are a concern. We will see more viruses emerging that can jump from animals to people, some with pandemic potential. There are so many coronaviruses, and our interactions with nature (and the stress we’re putting Mother Nature under) mean the risk of inter-species transmission events will only increase. The more coronaviruses that we’re exposed to, the greater chance we encounter one that we’re susceptible to. The more coronaviruses that can infect us, the greater the chance they can recombine further to become more infectious to people.
However, this isn’t one I’m worried about. It’s worth studying more to make sure it’s not an issue and better understand the situation, but I won’t lose sleep over it.
This is best taken as another reminder that zoonotic threats are always lurking. We need to be prepared, be vigilant, have good surveillance systems and ensure we communicate – and treat our planet and its inhabitants with a little more respect.