The new discovery of coronaviruses in bats with unprecedented similarities to SARS-CoV-2 — the virus that causes COVID-19 – could support the hypothesis that the pandemic originated in the limestone caves of Southeast Asia and southern China. According to experts, the newly-discovered bat coronaviruses may have the “same potential” to infect humans as the early strains of Covid that began the pandemic. Since the mysterious emergency of SARS-CoV-2 back in late 2019, researchers have undertaken studies of various animals — including horseshoe bats and pangolins — in an attempt to determine the virus’ origin as well as species that might serve as potential reservoirs and intermediate hosts.
In their present investigation, virologist Marc Eloit, of the Pasteur Institute in Paris, and colleagues analysed 645 individual bats found living in the limestone caves in northern Laos, on the Indochinese peninsula.
The flying mammals included in the testing, the team said, represented 46 different species belonging to six families.
The researchers found three viruses circulating within the bat populations that appear to be “closely related” to SARS-CoV-2, the virus that causes COVID-19.
Prof Eloit said: “The existence of these viruses discovered in the bat animal reservoir backs up the theory that SARS-CoV-2 may originate from bats living in the vast karst highlands in the Indochina peninsula, which stretches across Laos, Vietnam and China.”
The three previously unfamiliar viruses have been given the soporific names of BANAL-103, BANAL-236 and BANAL-52.
Most relevant among the similarities between the bat viruses and SARS-CoV-2 was the semblance between the genetic sequences that encode the so-called ACE2 binding regions on the viruses’ spike proteins.
ACE2 is a protein found in cells that line the upper and lower respiratory tract, among other parts of the body, that is normally involved in signalling between cells.
However, it can be exploited by the Covid virus, which attaches itself to the receptor using its binding regions as the first step in entering and infecting a healthy cell.
READ MORE: EU loses €25bn as UK and Switzerland strike OWN ‘alliance’
This theory has recently received a boost from the apparent discovery of genetic material from a unique viral variant in soil samples collected from King George Island, Antarctica, back in late 2018–early 2019.
Experts have said that the virus was not collected in Antarctica, but instead that during analysis of the soil was accidentally mixed with that of another sample processed at the Sangon Biotech sequencing facility in Shanghai.
The Wuhan Institute of Virology — the facility at the centre of the “lab leak” hypothesis — is known to use Sangon Biotech to process its samples.
Further investigation has suggested that the hosts of the unique variant were likely hamster or green monkey cell lines — both of which are used in laboratories to study diseases.
Mutations in the virus suggest it is possible it might bridge the gap between the original bat coronavirus and the one that first appeared in Wuhan.
However, not only is the relationship between the viruses uncertain, but the timing of the sample contamination is also unclear.
The virus could predate the emergence of Covid in Wuhan if the mix-up happened in December 2019 — but if the accident occurred in early 2020, it is more likely that the virus came from an early experiment to understand the outbreak.