Alarmed by the relentless westward migration of bird flu from Asia, European animal health and food safety experts met in crisis session today to plot containment strategies.

Health experts also met here to discuss plans for coping should the virulent flu strain make the jump from bird to man as many fear.

New cases of bird flu have been identified in poultry from Turkey and Romania. The World Health Organization (WHO) has confirmed that the Turkish birds were infected with the H5N1 strain.

It’s not yet known whether the cases in Romania were caused by the same strain, but it’s likely that will turn out to be so, according to the WHO.

The H5N1 strain is easily transmissible among birds, but for the present far less adept at jumping to humans or causing easily transmitted disease in people. Nearly all humans known to have been infected with the H5N1 strain have been in close contact with infected birds, or were close relatives of people who had such contact.

Among 60 people who have died from infection with avian flu, only one was believed to have caught the infection from another person.

Health authorities worldwide are concerned, however, that with a few key mutations the virus could become the source of a global influenza pandemic that would rival the so-called Spanish Flu of 1918-1919, which killed an estimated 675,000 people in the United States and between 20 million and 40 million worldwide.

In both Turkey and Romania, infected poultry were found near flyways for migratory birds; the H5N1 strain has been documented in migratory geese and ducks.

Members of the EU’s Standing Committee on the Food Chain and Animal Health met to discuss means of reducing contact between migratory and domesticated birds in high-risk areas. Avian flu experts also met separately to plot public health responses to possible human exposures to infected animals.

Following discovery of bird flu in Kiziksa, Turkey, located 80 miles southwest of Istanbul, more than 5,000 birds have been slaughtered, reported Mehdi Eker, Turkey’s minister of agriculture. In addition, nine people from two families who came into contact with infected pigeons in western Turkey have been hospitalized for observation, according to country’s Anatolian news agency.

A local health official reported that there were no signs of illness in the nine people, and that the houses of the two families involved have been disinfected.

The European Commission, which acts to coordinate and implement EU policy, has banned the importation into member countries of poultry products and live birds from Romania and Turkey.

WHO recommended that “travelers to areas experiencing outbreaks of highly pathogenic H5N1 in poultry should avoid contact with live animal markets and poultry farms. Large amounts of the virus are known to be excreted in the droppings from infected birds. Populations in affected countries are advised to avoid contact with dead migratory birds or wild birds showing signs of disease.”

Experts consider exposure risk to human to be greatest during slaughtering, plucking, butchering, and preparation of poultry for cooking.

“There is no evidence that properly cooked poultry or poultry products can be a source of infection,” according to a WHO statement.

Meanwhile, news out of Tokyo and Wisconsin fanned the fears about an avian flu pandemic. In the Oct. 14 issue of Nature, Yoshihiro Kawaoka, Ph.D., and colleagues reported that a Vietnamese girl infected with the H5N1 strain had a viral mutation that was resistant to Tamiflu (oseltamivir) at standard preventive doses. The girl was treated for seven days at higher therapeutic doses, and was later discharged from the hospital.

The girl, who did not have known direct contact with poultry, had cared for her 21-year-old brother, who was infected through bird handling, the investigators reported.

“The timing of infection in these two patients, together with the lack of known interaction of the girl with poultry, raises the possibility that the virus could have been transmitted from brother to sister,” the authors wrote.

Genetic sequencing of a viral isolate from the girl showed a mutation in H5N1 in a gene that encodes for the enzyme neuraminidase, and this change had made the virus partially resistant to Tamiflu. Both Tamiflu and Relenza (zanamivir) are believed to work by inhibiting viral neuraminidase, thereby preventing the aggregation and release of new infective viral particles.

“We don’t know how frequently this kind of mutation can appear,” said Yoshihiro Kawaoka, a virologist at the University of Tokyo in Japan and the University of Wisconsin in Madison. “We are relying too heavily on Tamiflu,” he adds. “We need more drugs.”

In laboratory tests, the resistant virus was shown to be susceptible to Relenza, however.

Dr. Kawaoka said that health authorities should consider stockpiling Relenza and recommending that only therapeutic dosages of Tamiflu be administered.

“We’ve been watching for this change [in the virus],” he said. “This is the first, but we will see others. There’s no question about it.”

Also today, at a news conference following a meeting in Paris with French president Jacques Chirac and Philippe Douste-Blazy, the French foreign minister, Secretary of State Condoleezza Rice called for “complete transparency about what is going on with avian flu.”

She added, “The world should not be caught unawares by a very dangerous pandemic because countries refuse to share information, and so that is our very strong concern.”