A SARS-like virus has infected a fourth person in Britain.
Twelve people worldwide have contracted the infection, known as novel coronavirus. Five have died.
The virus was unknown in humans until a few months ago. Most of the infected lived or had recently been in the Middle East.
The World Health Organisation issued a global alert on 23 September.
British health officials say the latest patient is thought to have caught the virus from one of two family members who were already being treated in intensive care.
Experts say the risk to the general population remains small.
As well as Britain, the disease has affected people in Saudi Arabia, Jordan and Germany.