The UK is on alert as the global health watchdog has warned countries to look out for unusual flu cases after a deadly outbreak of swine influenza.
More than 80 people have died of pneumonia in Mexico after contracting a flu-like virus and many others – including children in a New York school – have fallen ill in the United States and Mexico.
A man in the UK, was admitted to hospital with “flu-like symptoms” after arriving at Heathrow on a flight from Mexico City.
He has since been cleared of the illness.
A spokesman for Northwick Park Hospital said the cabin crew member does not have swine flu: “All the tests have come back negative.”
World Health Organisation (WHO) director-general Margaret Chan said the outbreak in Mexico and the US constituted a “public health emergency of international concern”.
It means nations will be expected to step up reporting and surveillance of the contagious respiratory disease, which she said had “pandemic potential”.