What is the virus causing illness in Wuhan?
It is a novel coronavirus – that is to say, a member of the coronavirus family that has never been encountered before. Like other coronaviruses, it has come from animals, or possibly seafood. Many of those infected either worked or frequently shopped in the Huanan seafood wholesale market in the centre of the Chinese city. New and troubling viruses usually originate in animal hosts. Ebola and flu are examples.
What other coronaviruses have there been?
Severe acute respiratory syndrome (Sars) and Middle Eastern respiratory syndrome (Mers) are both caused by coronaviruses that came from animals. Although Mers is believed to be transmitted to humans from dromedary camels, the original hosts for both coronaviruses were probably bats. The first cases of Sars were in China in late 2002. The authorities played them down and were subsequently much criticised because the virus spread virtually unchecked to 37 countries, causing global panic, infecting more than 8,000 people and killing more than 750. Mers appears to be less easily passed from human to human, but has greater lethality, killing 35% of about 2,500 people who have been infected.
What are the symptoms caused by the Wuhan coronavirus?
The virus causes pneumonia. Those who have fallen ill are reported to suffer coughs, 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 are known to have been already in poor health.
Is the virus being transmitted from one person to another?
Human to human transmission has been confirmed by China’s National Health Commission, although it does not appear to be happening easily as was the case with Sars. As of 21 January the Chinese authorities had acknowledged 291 cases and six deaths. Modelling carried out by Imperial College experts has suggested there may be more than 1,700 cases. Those that are mild may not be detected at all.
How worried are the experts?
There are fears that the coronavirus may spread more widely and person to person during the week-long Chinese new year holidays, which start on 24 January, when millions of people travel home to celebrate. At the moment, it appears that people in poor health are at greatest risk, as is always the case with flu. But the authorities will be keen to stop the spread and anxious that the virus will become more potent than so far appears.