Animal-human transmission of virus increasing, cautions virologist Sunit Singh

The novel coronavirus (nCoV 2019) is one more example of viruses jumping from animals to humans, quickly adapting to humans, and then spreading fast through air, says Sunit K Singh, a leading Indian virologist.

Though a lot more has to be known about the virus that originated in Wuhan in China, the biggest lesson is, “Humans should know their boundaries and not invade the territories of wild animals; control eating habits as we get exposed to new viruses”, Singh says.

Ebola, SARS and MERS are classic examples in the past two decades of viruses spreading from animals to humans. There are at least another 15 reported cases, mostly in Africa, says Sunit, who heads the Molecular Biology unit at the Institute of Medical Sciences, of the Banaras Hindu University (BHU), Varanasi.

Bats, for example, harbour 70 types of viruses. If humans enter their spaces for food, anthropology or construction activity, they get exposed. If they have aerosolic organisms, it’s easy for humans to get infected, especially through the food route. In the case of SARS (2003), the virus spread from bats, transferred to civets, which are eaten in Hong Kong (where it broke out). Similarly, MERS (Middle East respiratory syndrome), spotted in 2012 in Saudi Arabia, spread through camels to humans. People in Africa and China eat wild animal meat too, exposing them to the risks.

With no drug or vaccine available to halt nCoV, the best bet is to keep a distance from the infected and be in quarantine for two weeks in a specified hospital, which the Indian government has initiated, he says.

Similarity with SARS

“Airborne viruses and pathogens releasing aerosolic organisms into the environment, when an infected person sneezes, can cause respiratory problems. They do not require a visa or a passport, hence they cross borders easily and rapidly with movement of people”, he told BusinessLine in a telephonic interaction.

From the available information, nCoV appears similar to SARS with 80 per cent of its genomic structure being the same. Whether it originated from bats, fish or whichever animal, the infection has transformed to ‘human to human’. It has adapted to the human system and is rapidly infecting people in close contact, warned Singh, who is part of a Virology Forum that promotes awareness and coordinated development.

According to the Atlanta-based US Centre for Disease Control and Prevention (CDC), coronaviruses are a group of viruses that cause respiratory tract illnesses, including the common cold, but can sometimes be more serious, particularly for infants, the elderly and patients with weak or compromised immune systems.

Asked about the capabilities existing in India to study the viruses, Singh said to understand pathogens transmitted through the aerosolic route, a minimum of BSL3 (biosafety level 3) was needed and at least 8-10 centres exist in the country. These exist in the National Institute of Virology (NIV), Pune, and an institute in Bhopal specialising in animal viruses.

Internationally, several companies are investigating whether the existing antiviral drugs can be repurposed to treat nCoV. Some of these have been used against SARS and MERS.

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