A group of bat viruses closely related to the deadly Middle East respiratory syndrome coronavirus (MERS-CoV) could be one small mutation away from spilling over into human populations and potentially causing the next pandemic, according to a new study.

Researchers from the Washington State University (WSU), the California Institute of Technology and the University of North Carolina studied a group of coronaviruses known as merbecoviruses— the same viral subgenus that includes MERS-CoV — to better understand how they infect host cells

They found that while most merbecoviruses appear unlikely to pose a direct threat to people, one subgroup known as HKU5 possesses concerning traits, according to a statement by WSU.

Merbecoviruses have received limited attention apart from MERS-CoV, a zoonotic coronavirus first noted in 2012 that is transmitted from dromedary camels to humans. It causes severe respiratory disease and has a mortality rate of approximately 34 per cent.

Like other coronaviruses, merbecoviruses rely on a spike protein to bind to receptors and invade host cells.

The team used virus-like particles containing only the portion of the spike responsible for binding to receptors and tested their ability to infect cells in the lab.

“While most merbecoviruses appear unlikely to be able to infect humans, HKU5 viruses — which have been found across Asia, Europe, Africa and the Middle East — were shown to use a host receptor known as ACE2, the same used by the more well-known SARS-CoV-2 virus that causes COVID-19. One small difference: HKU5 viruses, for now, can only use the ACE2 gene in bats, but do not use the human version nearly as well,” the statement by WSU noted.

Another study that came out earlier this year, analysed one HKU5 virus in China that has already been documented to have jumped into minks, showing there is potential for these viruses to cross species-barriers.

“These viruses are so closely related to MERS, so we have to be concerned if they ever infect humans. While there’s no evidence they’ve crossed into people yet, the potential is there — and that makes them worth watching,” the statement quoted Michael Letko, a virologist at WSU’s College of Veterinary Medicine who led the study.

The research was published in the journal Nature Communications.

Source: Down To Earth.