What is the virus causing illness in Wuhan?
It is a novel coronavirus – a member of the coronavirus family never been encountered before. Like other coronaviruses, it has come from animals.
Many of those infected either worked or frequently shopped in the Huanan seafood wholesale market in the centre of the Chinese city, which also sold live and newly-slaughtered animals. 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 dromedaries, the original hosts for both coronaviruses were probably bats.
There are suspicions the new coronavirus may have originated in bats or snakes, and possibly then was transmitted to humans via an intermediary species. In 2002 Sars 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 per cent 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. In severe cases there can be organ failure. As this is viral pneumonia, antibiotics are of no use. Antiviral drugs we have against flu will not work.
If people are admitted to hospital, they may get support for their lungs and other organs as well as fluids. Recovery will depend on the strength of their immune system. Many of those who have died had 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. In the past week, the number of confirmed infections has more than tripled and cases have been found in 13 provinces, as well as the municipalities Beijing, Shanghai, Chongqing and Tianjin.
The virus has also been confirmed in Hong Kong, Macau, Japan, Nepal, Singapore, South Korea, Taiwan, Thailand, the United States, and Vietnam. The actual number to have contracted the virus could be far higher as people with mild symptoms may not have been detected.
How worried are the experts?
There were fears that the coronavirus might spread more widely during the week-long lunar new year holidays, which started on January 24th, when millions of Chinese travel home to celebrate, but the festivities have largely been cancelled and Wuhan and other Chinese cities are in lockdown.
A key concern is the range of severity of symptoms – some people appear to suffer only mild illness while others are becoming severely ill. This makes it more difficult to establish the true numbers infected and the extent of transmission between people. But the authorities will be keen to stop the spread and will be anxious that the virus could become more potent than it so far appears.
Why is this any worse than normal influenza?
It is not known how dangerous the new coronavirus is – more data is needed. Another key unknown, of which scientists should get a clearer idea in the coming weeks, is how contagious the coronavirus is. A crucial difference is that unlike flu, there is no vaccine for the new coronavirus, which means it is more difficult for vulnerable members of the population to protect themselves.
Cause for panic?
No. The spread of the virus outside China is worrying but not an unexpected development. The key concerns are how transmissible this new coronavirus is between people and what proportion become severely ill and end up in hospital. Often viruses that spread easily tend to have a milder impact.
Healthcare workers could be at risk if they unexpectedly came across someone with respiratory symptoms who had travelled to an affected region. Generally, the coronavirus appears to be hitting older people hardest, with few cases in children.
– Guardian