Covid-like virus in native UK bats raises spillover risk: Scientists

NEW DELHI: A team of international scientists have identified new bat species native to the UK that carry Covid-like virus, and may be just a few mutations away from infecting humans.

The scientists, including from the Imperial College London and University of Nottingham, screened for coronaviruses 48 faecal samples from 16 of the 17 bat species breeding in the UK.

They recovered nine (two novel) complete genomes across six bat species: Four alpha coronaviruses, an MERS-related betacoronavirus, and four closely-related sarbecoviruses (a subgroup of coronavirus).

The four sarbecovirus genomes were recovered from two distinct horseshoe bat species, R. ferrumequinum and R. hipposideros.

Horseshoe bats (Rhinolophidae) are considered the reservoir of many zoonotic viruses - which jump from animals to people including the close relatives of the viruses that cause severe acute respiratory syndrome and Covid-19.

The sarbecoviruses RhGB07, RhGB08, RfGB01, RfGB02 share 97-100 per cent identity with RhGB01.

RhGB01 is linked with both SARS-CoV-2 (responsible for the current pandemic) and SARS-CoV (responsible for the initial 2003 SARS outbreak in humans).

The study "demonstrated that RhGB07 can bind and use the human ACE2 receptor for infecting human cells", the researchers wrote in the yet to be peer-reviewed paper, published on a pre-print website. ACE2 receptor is the entry point for the Covid virus to get into the human body and infect a wide range of human cells.

However, the binding affinity of RhGB07 spike to the human ACE2 receptor was found to be approximately 17-fold lower than that to SARS-CoV-2 spike.

"We provided evidence that at least one sarbecovirus isolated from UK horseshoe bats can bind human ACE2 receptors in vitro," they noted.

"But our findings indicate that the RhGB01-like viruses likely require further adaptations, particularly in their spike proteins, before they can make a zoonotic jump," the researchers said.

In addition, the spike proteins of these sarbecoviruses are just one mutation away from a furin cleavage site (FCS) that enhances infectivity in other coronaviruses, including SARS-CoV-2.

"The emergence of the Covid-19 pandemic in 2019 is a sobering reminder of the massive impact of zoonotic viruses on global health and economy. Despite this, genomic surveillance in wildlife remains limited," the researchers said.

While in the study," the UK sarbecoviruses would require further molecular adaptations to infect humans, their zoonotic risk is unknown but warrants closer surveillance," they added.