Researchers in Wuhan report new coronavirus that could threaten humans

Five years after the outbreak of the corona pandemic, worrying virus news is again emerging from the laboratory in Wuhan, China, the city where it all began. Researchers report the discovery of a new corona variant that occurs in bats and can also infect human cells. Scientists from the Guangzhou Academy of Sciences, Wuhan University and the Wuhan Institute of Virology published about this in the scientific journal Cell . The research was led by the renowned virologist Shi Zhengli, also known as the “bat woman” because of her track record in researching SARS-like coronaviruses in bats.

Bats as corona carriers

Bats are notorious carriers and spreaders of various types of coronaviruses. The best known is SARS-CoV-2, the cause of the corona pandemic, which is believed (but never confirmed) to have reached humans from bats by a roundabout route. Fortunately, not all coronaviruses can infect humans, but with an eye on a possible new pandemic, scientists are keeping a close eye on variants that seem to be able to do so.

Shi’s group came across HKU5-CoV-2, a merbecovirus, which falls under the coronaviruses. The virus was found in a Hong Kong pipistrelle bat. This new variant, from the same family as the MERS virus, is able to enter human cells via the same route as SARS-CoV-2 did, although it appears to be a bit more difficult.

ACE2 receptor

HKU5-CoV-2 appears to be able to bind to the ACE2 receptor on the outside of human cells. Once attached, the virus particle can find its way into the cell and replicate from there. ACE2 is the same receptor that also allowed SARS-CoV-2 to enter humans. This receptor is found on cells in both the upper and lower respiratory tract. When a virus is in the upper respiratory tract, it can usually spread quickly between people, but whether this is also the case with HKU5-CoV-2 is not yet known.

What worries Bart Haagmans, virologist at Erasmus MC in Rotterdam, is that there has not been any human infection with a variant of the merbecovirus before. "There is therefore a good chance that there is no immunity to the virus in the population, as there probably is now with variants of SARS-CoV-2."

Asymptomatic

On the other hand, it is not yet clear how pathogenic this virus can be for humans, and whether this virus can easily spread between people, Haagmans emphasizes. That question partly predicts whether a virus can become a pandemic, and what the impact of that will be. "An infection with SARS-CoV-2 was very dangerous for people with poor health, but was also mild or asymptomatic for many people: they passed it on without realizing it. Then things happen very quickly."

The entry of the new bat virus into the human cell does not seem to be going very smoothly, at least less smoothly than with SARS-CoV-2. "Relatively many virus particles are needed before one of them manages to enter a cell," says Haagmans. The virologist does not rule out that this virus, like the omicron variant of corona, will mutate over time in such a way that it enters more easily.

Mink farming

“Disturbing,” he calls the fact that another Chinese research group recently Nature published about a variant that is very similar to HKU5-CoV-2. That variant was found in mink, which according to Haagmans could mean that the virus jumped from a bat. "That is probably what happened with SARS-CoV-2 at the time: the chance that a bat directly infects a human is small, but as soon as the virus circulates in the fur industry, where thousands of animals are kept together, it can quickly mutate and jump to humans."