Romanian agricultural authorities confirmed yesterday that chickens and ducks that died this month on a farm near the Danube River delta were infected with the deadly H5N1 influenza virus, according to press reports and an infectious diseases Web site.

The confirmation marks the arrival in Europe of the bird flu virus that has circulated in Southeast Asia since 2003, resulting in the deaths of 60 people and 140 million birds. Tests completed last week also revealed that H5N1 was responsible for a deadly outbreak on a turkey farm in Turkey on Oct. 1.

The westward migration of H5N1 has been unusually rapid. The previous known western limit of its range was Mongolia, Kazakhstan and Siberia, where it was found in August. Migrating birds are the presumed vehicle for the virus's introduction into Romania and Turkey, although there is no proof.

Spread of the virus through Europe could be devastating to the poultry industry. The appearance of H5N1 in a flock generally leads to immediate culling of the entire flock, and often of nearby flocks as well.

Ilinca Ilie, the press attache at the Romanian Embassy in Washington, would not confirm the finding. The ProMED infectious diseases Web site, however, said European press reports carried a statement from an official of Romania's veterinary and animal health authority confirming the finding of H5N1.

Samples from five birds were examined at a laboratory in Weybridge, England. Results announced last week showed the Romanian virus fell into the H5 category, and its further characterization as H5N1 was expected.

A posting on the ProMED site yesterday also reported that Macedonian television had reported the death of at least 80 birds on a farm in the Serbian province of Kosovo, raising the possibility that H5N1 might be there as well.

The European Union's Committee on the Food Chain and Animal Health met Friday to decide on measures to prevent the spread of avian influenza in the continent. According to an E.U. press release, countries will be expected to try to reduce contact between wild and domestic birds.

"This could include keeping poultry indoors in high-risk areas" near migratory flyways and ponds, rivers and wetlands where wildfowl congregate, the statement said. Farmers in those areas would be expected to report any change in their birds' health, including a fall in egg production.

George Happ, a biologist at the University of Alaska, said migratory birds are a probable source of H5N1's introduction into Europe, although there is no definitive proof of how the disease has spread.

"It's easy to blame wild birds. But we don't know which kind, if any, brought it," he said.

Happ is leading a project that began collecting fecal samples from Alaskan birds last spring in an effort to catalogue the variety of influenza viruses they carry. The ecology and inter-species transfer of flu viruses in wild waterfowl are largely unknown, as are details of the birds' flight routes.

He said he thought it was very unlikely that individual birds carried the virus directly from Asia. Instead, he said, it would be more likely to have hopscotched west, passed to several groups of birds whose migratory paths crossed.

He declined to speculate how easily or quickly H5N1 could get to the Americas.

A Romanian official in Ceamurlia de Jos holds a dead domestic duck culled Friday on suspicion of being infected with bird flu, which is spreading west.