‘NeoCov’ became the most searched term on Google by Friday last (January 28) in India after Chinese researchers called world’s attention to a coronavirus strain that they said was detected in a population of bats in South Africa that could likely pass on to humans as part of zoonosis (disease transmitted to humans from animals).

The Chinese sounded as if another variant of the coronavirus was ‘a step away’ from being let loose on an unsuspecting world even as the latter was busy trying to see off the latest Omicron variant-induced wave.

Non peer-reviewed study

“NeoCov could penetrate human cells in the same way as the Covid-19 virus, and is only one mutation away from becoming dangerous for humans,” the Chinese had said in a yet-to-be peer-reviewed study posted on the preprint repository BioRxiv.

The World Health Organisation (WHO) said that it is aware of the development, but the virus requires further study to ascertain if it poses a risk to humans, the WHO was quoted as saying by Russian news agency TASS.

The source of 75 per cent of infectious diseases in humans is wild animals, the WHO said. Coronaviruses are often found in animals, including bats, a natural reservoir. However, medical experts in India downplay the perceived threat from NeoCov .

MERS-CoV precedent

Rajeev Jayadevan, Vice-Chairman of the Kerala Research Cell of the Indian Medical Association, recalled that MERS-CoV (Middle East Respiratory Syndrome) was one of three main coronaviruses that caused large-scale human fatalities. It had struck the world 10 years ago, with an estimated mortality of 35 per cent.

Researchers studying the origins of this virus looked for similar viruses in bats, which are common reservoirs for such viruses. Even though the MERS-CoV virus is thought to have jumped to humans from camels, it is believed that bats may have given the virus to camels many years ago.

The NeoCoV virus was one such virus discovered in 2014, gnomically similar to MERS-CoV virus, but there are no known infections or fatalities among humans just yet.

‘Altering key to fit lock’

The current interest was generated after Chinese researchers discovered that the virus uses the ACE2 receptor to enter bat cells in certain types of bats. They speculated that the virus would be able to change itself in ways to enable it to attach to the ACE2 receptor of the human cell, which is structurally different.

“But this is like altering key to fit a different lock, which is extremely unlikely, given the enormous numbers of viruses that live peacefully in other mammals and yet do not cause a pandemic among humans,” Jayadevan said.

NeoCov, an old virus

In this context, it is also pertinent to point out that the estimated mortality rate of 35 per cent of the MERS-CoV virus was based only on lab-confirmed cases. This will invariably be lower if all cases of asymptomatic and mild infections were included in the denominator, a fact acknowledged by the WHO.

Shashank Joshi, Member, Maharashtra State Covid-19 Task Force and Chair of International Diabetes Federation, tweeted that NeoCov is an old virus related to MERS-CoV which enters cells via DPP4 receptors. It can use ACE2 receptors of bats but not humans unless a new mutation occurs. The rest is all hype.