The World Health Organisation on Saturday urged countries to be vigilant over  the spread of a potentially fatal SARS-like virus after a new case in Britain  brought the global number to 12.

“Based on the current situation and available information, WHO encourages all  Member States to continue their surveillance for severe acute respiratory  infections (SARI) and to carefully review any unusual patterns,” the United  Nations health agency said in a statement.

On Friday, British health authorities said that a third member of a family  had been diagnosed with so-called novel coronavirus, but was not in danger.

“Although this new case offers further indications of person-to-person  transmission, no sustained person-to-person transmission has been identified,”  said the WHO.

Clusters of cases, and cases among health workers, should be thoroughly  investigated wherever they occur, it underlined.

Britain’s Health Protection Agency said the latest person to contract the  virus was a relative of two other cases announced earlier this week.

The first member of the family, who was confirmed on Monday as having the  virus, had recently travelled to the Middle East and Pakistan. The two relatives  had no recent travel history.

A total of 12 cases have been reported to the WHO, with five of them fatal —  three in Saudi Arabia and two in Jordan.

Coronaviruses are to blame for most common colds but can also cause SARS  (severe acute respiratory syndrome).

A SARS epidemic killed more than 800 people when it swept out of China in  2003, sparking a major international health  scare.