Chinese researchers said Thursday they had found a batch of new coronaviruses in bats including one that may be the second-closest yet, genetically, to the Covid-19 virus.
According to the researchers, their discoveries in a single, small region of Yunnan province, southwestern China show just how many coronaviruses there are in bats and how many have the potential to spread to people.
Weifeng Shi of the University of Shandong and colleagues collected samples from small, forest-dwelling bats between May, 2019 and November, 2020. They tested urine and feces as well as taking swabs from the bats’ mouths.
“In total, we assembled 24 novel coronavirus genomes from different bat species, including four SARS-CoV-2 like coronaviruses,” the researchers wrote in a report published in the journal Cell.
One was very similar, genetically to the SARS-CoV-2 virus that’s causing the current pandemic, they said — a viral sample called RpYN06 taken from a horseshoe bat species called Rhinolophus pusillus.
It would be the closest strain to SARS-CoV-2 except for genetic differences on the spike protein, the knob-like structure that the virus uses when attaching to cells, they said.
“Together with the SARS-CoV-2 related virus collected from Thailand in June 2020, these results clearly demonstrate that viruses closely related to SARS-CoV-2 continue to circulate in bat populations, and in some regions might occur at a relatively high frequency,” they wrote.
Researchers are trying to find where SARS-CoV-2 came from. Although a bat is a likely source, it’s possible the virus infected an intermediary animal. The SARS virus that caused an outbreak in 2002-2004 was tracked to an animal called a civet cat.
“Bats are well known reservoir hosts for a variety of viruses that cause severe diseases in humans and have been associated with the spillovers of Hendra virus, Marburg virus, Ebola virus and, most notably, coronaviruses. Aside from bats and humans, coronaviruses can infect a wide range of domestic and wild animals, including pigs, cattle, mice, cats, dogs, chickens, deer and hedgehogs,” they wrote.
Most of the samples came from species of horseshoe bats. In 2017, researchers sampling a cave in Yunnan found viruses very close genetically to the SARS virus in horseshoe bats.
Three of the samples described in Thursday’s report were also close to SARS genetically.
“Our study highlights the remarkable diversity of bat coronaviruses at the local scale, including close relatives of both SARS-CoV-2 and SARS-CoV,” they wrote. The bat species they sampled are common across Southeast Asia, including southwest China, Vietnam, Laos and elsewhere.
Although there’s some controversy about the origin of the coronavirus pandemic, a World Health Organization report said the most likely source is an animal — probably a bat.
People hunt and eat bats, and bats can infect other animals that are also hunted and eaten by people. Viruses can infect people when they handle or slaughter the animals.