But no change on travel advice
The World Health Organisation (WHO) has declared a swine flu pandemic as the virus continues to spread globally.
The first death in the UK from the virus, that of 38-year-old Jacqueline fleming in Scotland, has also been announced.
WHO director-general Dr Margaret Chan said: "The virus is contagious, spreading easily from one person to another, and from one country to another. As of today, nearly 30,000 confirmed cases have been reported in 74 countries.
"On the basis of available evidence, and these expert assessments of the evidence, the scientific criteria for an influenza pandemic have been met.
"I have therefore decided to raise the level of influenza pandemic alert from phase five to phase six. The world is now at the start of the 2009 influenza pandemic."
Despite being in the grip of the first global pandemic for more than 40 years, health authorities around the world have not changed their advice on travel as the alert refers to the spread, not the severity of the infection.
Dr Chan said: "WHO continues to recommend no restrictions on travel and no border closures."
A spokesperson for the UK Foreign and Commonwealth Office (FCO) said it had not changed its advice since the alert level was raised, but would review travel on an ongoing basis.
"We have reflected the change in the WHO alert level to six in our warnings about swine flu in our travel advice for all countries," the spokesperson said.
"The current advice takes into account the increased World Health Organisation alert level along with other information, including that of our own health authorities."
British Airways and Lufthansa both said they were continuing flights to Mexico, where the first case of swine flu was diagnosed, and all other countries.
"We work very closely with the German health ministry, but we have no plans to stop flights to any country because of swine flu," a Lufthansa spokesperson said.
A BA spokesperson said any decision to restrict travel would be taken based on advice given from the FCO.
www.fco.gov.uk www.who.int www.ba.com www.lufthansa.com