Two new coronaviruses have been identified that can infect people—and one came from dogs

As Nature reports, there is some good news on the COVID-19 front. Scientists are close to identifying the factors that provide immunity from being infected by the SARS-CoV-2 virus, and even a tiny amount of the right “neutralizing antibodies” appears to offer powerful protection. Combine that with previous studies showing that mRNA vaccines generate large amounts of these antibodies from a single dose, with new results showing that mixing doses of different vaccines can produce an even more potent response, and it appears that the world may have everything it needs to fend of the current pandemic—so long as those vaccines get to the nations, and people, who need them most. 

However, the COVID-19 pandemic continues to rage across the globe, and as an article in The Lancet shows, the latest wave of cases is hitting Africa particularly hard. A higher percentage of patients are turning up critically ill, and a higher percentage of that group is dying. Why this is happening, even in places where the healthcare system has not yet been overwhelmed by cases, isn’t clear. What is clear is that over a dozen nations in Africa have a vaccination rate of less than 1%. That’s not because of vaccine hesitancy—many of these same nations report some of the highest measures for trust in vaccine efficacy and safety. It’s because of simple lack of availability.

But as the world grapples with how to bring the ravages of SARS-CoV-2 to a close, Science reports that two more coronaviruses have been discovered that can infect people. One of those coronaviruses appears to have sent eight children to the hospital in 2018; its source was not some group of bats in a particular cave, or from people consuming wild animals in an exotic market.

Instead, these children may have caught this virus from dogs.

Flu viruses have a unique kit of interchangeable proteins on their surface. The frequent rotations through this set result in names like H1N1, which describes which parts of the flu toolkit are exposed in a particular variant. It’s what makes flu such a perennial disease, with the combination of proteins frequently rotating to provide a matchup not seen in years, or decades.

Coronaviruses don’t appear to have a similar mechanism. However, for viruses, they have a relatively large genetic description—about 30,000 letters worth of amino acids. And they seem quite prone not just to mutation, but to swapping out segments of that code with other coronaviruses. That exchange could be connected to what allows these viruses appear to move so easily move among different hosts. For example, back in 2002, a coronavirus found in one of the nocturnal cat-like mammals known as civets developed the right hardware to infect humans. The result was SARS-CoV, the virus behind SARS.

The reason that there are institutes of virology devoted to emerging coronaviruses is that they keep emerging. That’s probably always been true, but in the last few decades, new coronaviruses have made the leap to “can infect humans” with regularity.

Of course, that doesn’t always lead to a global pandemic. Many of the viruses that make the jump from animals to humans might not cause disease, or might not have the ability to be transmitted human-to-human, so never become widespread. Though hundreds of coronaviruses have been identified, only seven are known to cause illness in humans. Of those, four of the seven cause only mild to moderate disease. The exceptions are the viruses behind SARS, MERS, and COVID-19.

Still, three severe illnesses in a couple of decades is a frightening record for this family of viruses, and explains why researchers are looking closely at the latest two examples that will certainly turn the sickening seven into the icky eight. And possibly the noxious nine.

The virus that sickened a group of people in 2018 was found in Malaysia. And as an analysis in Clinical Infectious Diseases shows, it appears to contain segments found previously known canine coronaviruses, as well as some portions that line up with a coronavirus found in cats, and parts from another found in pigs. These things get around.

The dog-cat-pig virus appears to be responsible for a pneumonia-like illness among those infected. Which, for those who remember the first reports out of Wuhan, has a chillingly familiar ring. However, even if this does turn out to be the eighth coronavirus that can cause an illness in people, there doesn’t seem to have been any new cases since the initial cluster. It appears that this virus might not be well-adapted to people, and may not be contagious person-to-person. So while the cluster of cases is worth examining closely, it doesn’t seem to be cause for immediate alarm.

Similarly, the second new human-infecting coronavirus may be new to science, but it doesn’t seem to be the source of new cases of disease. This analysis is still in preprint, but it shows a suspected virus that may have generated a pronounced fever among a small number of children in Haiti in 2014-2015. In this case, the coronavirus appears to have made the jump from pigs. One thing that’s particularly interesting about this situation is that this virus comes from a group called delta coronaviruses. Every known coronavirus that can infect humans is a member of either the alpha or beta groups of coronaviruses. While those viruses are mostly associated with bats, delta coronaviruses—just as in this case—mostly infect pigs. The researchers note the flexibility of these viruses in infecting humans is worrisome, specifically because of how common delta coronaviruses are among pigs, and how common it is for pigs to live side by side with people.

Neither of the new viruses appears to represent anything like an immediate threat. However, together they make it clear that we still have a poor understanding of the group of viruses that has generated some of the worst diseases of the last century. And how important it is that governments continue to fund research into emerging viruses.