A German health institute said on Tuesday test results showed two women examined for a possible bird flu infection had not caught the disease now sweeping Asia.

A spokeswoman for the Bernhard Nocht Institute for Tropical Medicine in Hamburg said tests showed that the women, one of whom had just returned from a vacation in Thailand feeling ill and with a fever, were not suffering from bird flu.

"It is almost certainly a human strain of influenza and not bird flu," the spokeswoman said.

The alarm was raised after the woman, who returned from Thailand on Saturday, was taken to hospital complaining of sickness, dizziness and fever. Her female companion, who had no symptoms, was also tested.

Had they been confirmed as bird flu, the cases would have been the first in Europe in the latest epidemic, which has killed 12 people and affected 10 countries in Asia.

Officials from Hamburg's health authority and from the Robert Koch Institute in Berlin, Germany's top health institute, had said late on Monday it was very unlikely the women had bird flu.

But the scare sent shares in airline Deutsche Lufthansa and tour operator TUI tumbling because of fears it could affect bookings from German tourists.

Gerd-Dieter Burchard, the doctor treating the patient at the Hamburg institute, said late on Monday she was a young German who had had no contact with poultry in Thailand.

"It's a very low level of suspicion but we cannot rule it out and can take no risks," Burchard said at the time.

(Reuters)