A new coronavirus that can infect people recently was discovered from an unlikely source: a dog.
A research team was caught off guard when they analyzed the nasal swabs of pneumonia patients in a Malaysian hospital in 2018 and discovered eight of the patients were infected with a dog coronavirus.
Sure, dogs can get infected with coronaviruses and have for decades. People have been infected with human coronaviruses for a while as well, with some causing symptoms similar to what comes with the common cold.
But a dog coronavirus infecting a person?
Thinking they might have made a mistake, the researchers in Malaysia and at Duke University contacted a scientist known for her knowledge of coronaviruses: Anastasia Vlasova, an assistant professor of immunology and virology in Ohio State’s College of Food, Agricultural, and Environmental Sciences.
“I had never heard of a dog coronavirus infecting a person,” Vlasova said
She got to work growing enough of the virus to figure out its genetic makeup. Sure enough, examining its genome confirmed it was a dog coronavirus.
The virus is an alpha coronavirus and very different from the coronavirus causing the current COVID-19 pandemic, which is a beta coronavirus. Alpha and beta coronaviruses are kind of like cousins in a large family. Cousins, who so far, have taken pretty different paths in life.
More research is needed to determine whether this newly found coronavirus, which Vlasova and her colleagues named CCoV-HuPn-2018, can be passed from person to person and how well the human immune system can fend it off.
Vlasova offers some thoughts on this new virus and its potential.
At this point, you don’t need to worry. But we do need to continue to study this virus to see if it can spread from one person to another. If not, then after a dog infects a person, the virus will reach a dead end, and it can’t be spread further.
If the new dog coronavirus is found to be able to spread from one person to another, the human immune system may be capable of attacking the virus. That immunity can come from exposure to other coronaviruses, including the SARS-CoV-2 virus causing the COVID-19 pandemic.
Among the Malaysian patients infected with the new dog coronavirus, none died nor had long-term health effects. All but one of them were children, some under a year old. Very young children tend to be more susceptible to illness because of their developing immune system.
A portion of the genome of the virus is similar to the genetic makeup of pigs and cats. So, at some point, the virus likely exchanged genetic material with pig and cat coronaviruses.
That exchange could have happened when a dog coronavirus infected a cat, then the cat somehow infected a pig — with each infection causing a slight change in the original dog coronavirus.
Animal coronaviruses cross over into the human population much more often than we had thought in the past. It’s probably happening on a daily basis when different animal species come into close contact with people.
All known human coronaviruses came from animal coronaviruses that changed enough as a result of people being exposed to them. Coronaviruses change often, adding and losing their genetic material. After many genetic changes, also called mutations, the virus can take on enough similarity to a human coronavirus that it can gain the ability to infect a person.
Part of the reason coronaviruses can move from infecting one species to infecting another, including people, is because of the coronavirus’s spike protein, which is a key surface element of the virus.
The spike protein binds to cells in a new host or animal species. Once that binding happens, the coronavirus can enter a cell and begin to replicate. The spike of the CCoV-HuPn-2018 virus carries fragments of dog, cat and pig coronaviruses, which probably makes the virus capable of infecting these different species.
Another important part of this virus’s structure is a deletion of genetic material that was not found in any other dog coronaviruses.
While we understand why it’s so easy for coronaviruses to infect different host species, we don’t understand why some succeed and some end up nowhere. The immunity and the genetic makeup of the new host probably factors into it.
If the new dog coronavirus is found to be able to spread from one person to another, the human immune system may be capable of attacking the virus.
I want to study a mutation that occurred in the CCoV-HuPn-2018 virus in the region where the deletion of genetic material happened.
That deletion may have given the virus the ability to infect or to survive in people. I want to see how the virus operates with and without the mutation so we can better understand what this mutation allows the virus to do.
Our results may mean many dog coronaviruses can infect people or it may be that just one lineage of coronaviruses that can infect people. We don’t know.