Q&A: The new coronavirus
A new respiratory illness similar to the Sars virus that spread globally in 2003 and killed hundreds of people has been identified.
The World Health Organization says it appears "increasingly" likely that novel coronavirus can be passed between people in close contact.
What is this new coronavirus and should we be concerned?
What is this new virus?
The new virus is a type of coronavirus. Coronaviruses are a large family of viruses, which includes the common cold and Sars (severe acute respiratory syndrome). The new virus is not Sars.
There have been 34 confirmed cases of the infection around the world and 18 deaths.
Cases have been detected in Saudi Arabia and Jordan and have spread to Germany, the UK and France.
What does it do?
Coronaviruses cause respiratory infections in humans and animals. Patients have presented with fever, cough and breathing difficulties.
It causes pneumonia and, sometimes, kidney failure. Most of the people who have been infected so far have been older men, often with other medical conditions. Experts say they are not sure why we are seeing this pattern and if it will change over time.
It is also unclear how often people might develop mild disease.
How is it spread?
It is not known for certain. It is possible the virus is spread in droplets when an infected person coughs or sneezes.
The fact that close contacts appear to have been infected suggests that the virus does have limited ability to pass from person to person.
How dangerous is it?
Experts believe the virus is not very contagious. If it were, we would have seen more cases.
Coronaviruses are fairly fragile. Outside of the body they can only survive for a day and are easily destroyed by usual detergents and cleaning agents.
Public health experts in the UK have stressed that the risk to general population remains very low.
The greatest global concern, however, is about the potential for this new virus to spread far and wide. So far, person-to-person transmission has remained limited to some small clusters. There is no evidence yet that the virus has the capacity to become pandemic.
Can it be treated?
Doctors do not yet know what the best treatment is, but people with severe symptoms will need intensive medical care to help them breath. There is no vaccine to prevent.
What can I do to protect myself?
It's not known exactly how people catch this virus. However, some general measures may help prevent its spread - avoid close contact, when possible, with anyone who shows symptoms of illness (coughing and sneezing) and maintain good hand hygiene.
Where did it come from?
Experts do not yet know where the virus originated from. It may have been the result of a new mutation of an existing virus. Or it may be an infection that has been circulating in animals and has now made the jump to humans.
Is there any travel advice?
At the moment the World Health Organization says there is no reason to impose any travel restrictions. Travel advice will be kept under review if additional cases occur or when the patterns of transmission become clearer.
What about related viruses?
Coronaviruses are common viruses that most people get some time in their life. Their name comes from the crown-like spikes that cover their surface.
Human coronaviruses were first identified in the mid 1960s.
Other variants infect many different animals, producing symptoms similar to those in humans.
Most coronaviruses usually infect only one animal species or, at most, a small number of closely related species.
Sars was different: being able to infect people and animals, including monkeys, cats, dogs, and rodents.
Novel coronavirus doesn't seem to get passed from person to person easily, while the SARS virus did.
What impact did Sars have?
Sars is thought to have infected more than 8,000 people, mainly in China and South East Asia, in an outbreak that started in early 2003. The illness spread to more than two dozen countries in North America, South America, Europe, and Asia before the global outbreak was contained.
Experts established that Sars could spread by close person-to-person contact.
According to the World Health Organization, 774 people died from the infection. Since 2004, there have not been any known cases of Sars reported anywhere in the world.