When it comes to viruses, we can’t be too careful

Does the viral outbreak which started in Wuhan mean the end of the world? Probably not, says Luke O’Neill

ABRAND new virus has emerged in China and appears to be spreading to other countries. As scientists, we find this kind of thing fascinating. What is it? Where did it come from? Is it dangerous?

This can be the stuff of horror movies: Hollywood loves a good virus, as we saw in Outbreak starring Dustin Hoffman. But in this case there’s nothing to be too frightened of (yet) but we do need to keep an eye on it. As of yesterday, it had killed at least 42 people in China and infected more than 1,400.

What is it?

It’s in the same family of viruses as SARS and MERS which arose a few years ago. It has no name yet but it emerged in Wuhan.

SARS stands for

‘‘Severe Acute Respiratory Syndrome’’ while MERS stand for ‘‘Middle East Respiratory Syndrome’’ so the name might be WURS — ‘‘Wuhan Respiratory Syndrome’’, though the Chinese might not like how that would affect tourism in Wuhan. The name being used at the moment is ‘‘2019-nCoV’’. The “nCoV” stands for ‘‘New Corona Virus’’, as it belongs to the Corona virus family, so called because down a microscope (viruses are on average 40 times smaller than a bacteria) it looks like a crown. SARS and MERS are also coronaviruses. They cause a disease similar to flu, although the flu virus is in a different family.

Like SARS and MERS it came from animals, possibly seafood, bats or snakes. Viruses can live anywhere. It’s not known how the virus evolved, but from its DNA sequence it’s likely to be a descendant of SARS. If it’s a bad descendant, in that it might cause worse disease, that will worry people — though so far that doesn’t seem to be the case.

The first to be infected worked in a market in Wuhan so the virus probably arose from a creature being sold at the market, where black market wild animal meats were said to be also available.

The first cases of SARS itself were in China in late 2002. The authorities played them down and were subsequently criticised because the virus spread virtually unchecked to 37 countries, causing global panic, infecting more than 8,000 people and killing more than 750 including an outbreak in Toronto which killed 69 people, many of whom picked it up in hospitals. MERS appears to be less easily passed from human to human, but has greater lethality, killing 35pc of about 2,500 people who have been infected since 2012. It may have come from camels or, more likely, bats.

How dangerous is it?

The virus causes pneumonia. Those who become sick have a cough, fever and breathing difficulties. As this is viral pneumonia, antibiotics are of no use. Antiviral drugs may be used, but usually only lessen the severity of symptoms. If people are admitted to hospital, they may get breathing support as well as fluids. Recovery will depend on the strength of their immune system. Those who have died were already in poor health.

Concern about the virus ramped up when human to human transmission was confirmed in Guangdong province by China’s National Health Commission, though it does not appear to be happening easily, as was the case with SARS.

So far 14 medical personnel helping with coronavirus patients have also been infected. One doctor has died.

The Chinese are worried that the virus might spread more widely during the Chinese new year holidays which began this weekend, when millions usually travel home to celebrate. It’s a recipe for spreading the virus far and wide within China, but also in airports — leading to worldwide spread.

At the moment, it appears that people in poor health are at greatest risk. But the authorities will be keen to stop the spread and will be watching carefully to see if the virus becomes more potent than so far appears. Wuhan had planned to go ahead with 41 large-scale events — but last week it announced they were all “postponed.”

Schools and universities are on break for Spring Festival, but more than

100 extracurricular “cram” schools in Wuhan have cancelled classes. Travel restrictions have been imposed on 59million people across the country.

What might happen next? So far, it doesn’t seem as dangerous as SARS (which was more dangerous than flu) or to be spread as easily between humans which is good. SARS and MERS were eventually contained by case detection, isolation, quarantine and with contact tracing (which means finding and isolating the people who came into contact with someone infected). These measures broke the chain of transmission and will be adopted to control 2019nCoV. The virus will end up with nowhere to hide, at least in humans. It will instead hide in its other hosts — be it seafood or bats.

In the US, travellers from Wuhan have been routed to five airports where Centres for Disease Control and Prevention are screening passengers. Screening comprises looking out for travellers arriving who have a fever, cough or difficulty breathing. With careful monitoring and isolation of people with the virus the prospects of limiting the outbreak are good.

Another concern is if a ‘‘super spreader’’ emerges. These are carriers who infect a disproportionately high number of people. A “super spreader” is thought to have passed the virus on to 15 medical workers at a Wuhan hospital.

When it comes to viruses we can’t be too careful. As more people get infected, some might be found who are especially vulnerable. Because our immune systems haven’t seen it before, we have limited protection and this in turn might give rise to worse symptoms. It also might mutate and become more dangerous although that is impossible to predict and is deemed highly unlikely.

Watch this space however, as every five minutes we are getting more updates on the spread of the virus.

Luke O’Neill FRS is professor of biochemistry in the School of Biochemistry and Immunology at Trinity College Dublin

‘A “super spreader” is thought to have passed the virus on to 15 medical workers in Wuhan’