Researchers detail how SARS-CoV-2-related virus in Laos bats can infect humans

Researchers from France’s Pasteur Institute and the National University of Laos detail their findings that suggest bats may have been the source of the coronavirus that causes COVID-19 in humans in an article published online by Nature last month.

The researchers said they found that bats living in limestone caves in northern Laos host three genetically similar viruses that may have the same potential to infect humans as the early strains of SARS-CoV-2 that began the COVID-19 pandemic.

In an attempt to determine the origin of SARS-CoV-2, well as species that might serve as potential reservoirs and intermediate hosts, researchers have undertaken studies of various animals since the virus’ mysterious emergency back in late 2019.

Pasteur Institute’s virologist Marc Eloit and colleagues analyzed 645 individual bats representing 46 different species from to six families and discovered three previously unfamiliar viruses that they named BANAL-103, BANAL-236, and BANAL-52, said the article in Nature.

“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,” Eloit, a researcher at the University of Paris, and his colleagues explained in the paper they published in Nature.

The research showed that SARS-CoV-2 progenitor bat viruses can enter human cells via a previously unknown human ACE2 route. ACE2 is a protein that’s normally involved in signaling between cells, but, according to the researchers, the coronavirus exploits it to enter and infect a healthy cell by attaching itself to the receptor using its binding regions.

The similarity between the genetic sequences that encode the so-called ACE2 binding regions on the virus’s spike proteins is the most relevant among the similarities between the bat viruses and SARS-CoV-2, the researchers said.

According to the researchers, the bat viruses appeared to be even better at binding the ACE2 than the Wuhan’s SARS-CoV-2, despite the fact that they all lack a furin cleavage binding site found in the SARS-CoV-2 receptor-binding domain (RBD). The RBDs of the spike proteins of these viruses differ from that of SARS-CoV-2 by only one or two residues at the interface with ACE2, researchers said.

The need for One Health approach

International experts that the World Health Organization (WHO) sent to China in January 2021 concluded that the SARS-CoV-2 virus most likely jumped from bats to humans via an intermediate animal.

When the Laos bats’ study was first announced in September 2021, France24 quoted Martin Hibbert, Professor of Emerging Infectious Disease at the London School of Hygiene and Tropical Medicine pointing that “this work confirms the expected diverse nature of bat infecting coronaviruses and increases the evidence that natural spill-over events from bats to humans can occur.”

This risk underlines the need of having public health strategies that look beyond the human species, such as “One Health”, which recognizes links between the health of people, animals, and ecosystems, as Bio.News wrote.

The article also quoted BIO’s Connor McKoy as stressing that “the ability to prevent, prepare for, and respond to outbreaks of infectious diseases such as coronavirus, Ebola, Zika, avian influenza (HPAI) and MERS depends on an improved understanding of the interconnectedness of human, animal and environmental health.”

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