New SARS-like virus could infect humans

Washington: Scientists, including one of Indian-origin, have found a SARS-like virus in Chinese horseshoe bats that may infect humans without the need for
adaptation, and could set the stage for an outbreak.

The work, led by Ralph Baric, professor at University of North Carolina at Chapel Hill (UNC) comes on the heels of two recent high-profile outbreaks - Ebola and Zika - for which there are no vaccines.

"The capacity of this group of viruses to jump into humans is greater than we originally thought," said first author Vineet Menachery, from UNC. "While other adaptations may be required to produce an epidemic, several viral strains circulating in bat populations have already overcome the barrier of replication in human cells and suggest reemergence as a distinct possibility," Menachery said.

Researchers, including Sudhakar S Agnihothram, worked with SARS-like coronavirus sequences isolated from Chinese horseshoe bats, where SARS originated. Based on the sequences, they reconstructed the viruses to evaluate their potential to infect human cells and in mice.

They found that the newly identified virus, known as WIV1-CoV, could bind to the same receptors as SARS-CoV. They also showed that the virus readily and efficiently replicated in cultured human airway tissues, suggesting an ability to jump directly to humans.

"To be clear, this virus may never jump to humans, but if it does, WIV1-CoV has the potential to seed a new outbreak with significant consequences for both public health and the global economy," said Menachery.

The researchers also found that antibodies developed to treat SARS were effective in both human and animal tissue samples against WIV1-CoV, providing a potent treatment option if there were an outbreak. However, the limitation to treat with antibodies is the same as with ZMapp, the antibody approach used for Ebola - producing it at a large enough scale to treat many people.

Also, in terms of prevention, existing vaccines against SARS would not provide protection for this new virus due to slight differences in the viral sequence. SARS, short for severe acute respiratory syndrome, was first seen in an outbreak in 2002 and resulted in 8,000 cases and nearly 800 deaths, researcher said.

Spread through airborne contact, its onset presents symptoms similar to the flu with a dry cough but can accelerate rapidly to pneumonia, filling the lungs with fluid
and putting extreme stress on the body's immune system.

According to the Centres for Disease Control and Prevention, SARS' mortality rate can range from less than one per cent in patients below 24 years old to more than 50 per cent in patients aged 60 and older. Researchers believe that WIV1-CoV has the potential to induce similar results with proper adaptation to humans. The study was published in the journal PNAS.