An airline passenger who travelled to Heathrow Airport has been diagnosed with a potentially deadly Sars-like virus.
Public Health England (PHE) said the non-UK national was diagnosed with Middle East Respiratory Syndrome coronavirus (MERS-CoV) today after being taken to hospital with respiratory symptoms in the US.
The passenger had flown on a British Airways flight from Riyadh, the capital city of Saudi Arabia, to Heathrow on April 24, before transferring on to a flight to Chicago.
PHE has contacted UK passengers on BA Flight 262 who were sitting in the vicinity of the affected passenger, to provide them with health information, but stressed that the risk of infection was "extremely low".
Any UK passengers on the flight who have since become unwell or experienced respiratory symptoms such as shortness of breath have been urged to contact NHS 111.
PHE said it was also working with the US health authorities to contact any UK passengers on the onward flight, American Airlines Flight 99, from London to Chicago.
It is the first case of MERS-CoV in the US after diagnosis was confirmed by the United States Centre for Disease Control in Indiana.
Latest figures from the World Health Organisation (WHO) show that since mid-March, 111 people have tested positive in the Jeddah area of Saudi Arabia; the biggest single surge in the MERS-CoV outbreak since it was detected in April 2012, resulting in 31 deaths.
In total, there have been 401 confirmed cases of MERS-CoV infection in 12 countries including 93 deaths., according to the US Centre for Disease Control.
Three people have died so far in the UK as a result of the infection - including one man who died at the end of June. PHE said the last case to be detected in the UK was in February last year.
Cases have also been reported in France, Germany, Italy and Greece, across the Middle East in Egypt, Jordan, Qatar, Kuwait and Oman and in other countries including Malaysia, Philippines and Tunisia.
The period between exposure to MERS-CoV and when symptoms might develop is up to 14 days, according to PHE.
Any illness that passengers experience more than 14 days after the flight would not be related, it said.
Professor Nick Phin, head of respiratory diseases for Public Health England, said: " The risk is very low and human to human transmission of MERS-CoV is extremely rare, but we would ask any passengers from British Airways Flight 262 on 24 April to contact NHS 111 if they're experiencing respiratory symptoms or have felt unwell since their flight."