Compiled from BBC and Al Jazeera

A virus causing severe lung disease that started in China has spread to 27 other countries, including the UK.

The coronavirus had infected 78,159 people in China as of 26 February, with 2,717 of them dying.

What are the symptoms?

It seems to start with a fever, followed by a dry cough.

After a week, it leads to shortness of breath and some patients require hospital treatment.

The incubation period – between infection and showing any symptoms – lasts up to 14 days, according to the World Health Organization (WHO).

But some researchers say it may be as long as 24 days.

And Chinese scientists say some people may be infectious even before their symptoms appear.

How deadly is the coronavirus?

Based on data from 44,000 patients with this coronavirus, the WHO says:

• 81% develop mild symptoms
• 14% develop severe symptoms
• 5% become critically ill

The proportion dying from the disease, which has been named Covid-19, appears low (between 1% and 2%) – but the figures are unreliable.

Thousands are still being treated but may go on to die – so the death rate could be higher. But it is also unclear how many mild cases remain unreported – so the death rate could also be lower.

To put this into context, about one billion people catch influenza every year, with between 290,000 and 650,000 deaths. The severity of flu changes every year.

Can coronavirus be treated or cured?

Right now, treatment relies on the basics – keeping the patient’s body going, including breathing support, until their immune system can fight off the virus.

However, the work to develop a vaccine is under way and it is hoped there will be human trials before the end of the year.

Hospitals are also testing anti-viral drugs to see if they have an impact.