Russian officials have quarantined a large poultry farm in Siberia because of a suspected outbreak of bird flu, news reports said Saturday, Aug. 20, 2005. If confirmed, it would be the first major occurrence of the lethal virus among birds in Russia, and international health officials expressed concern that the disease had spread closer to Western Europe.

About 142,000 birds are being monitored at a commercial farm in the Omsk region of Siberia, the Russian news agency Interfax reported, quoting a federal agency that tracks the disease.

The presence of the deadly H5N1 strain of avian influenza was reported in July 2005 in Siberia, but only among wild birds and free-range chickens on small family farms.

International officials fear that in September migrating birds escaping the Russian winter might carry avian influenza across the Black Sea and into southeastern Europe and North Africa.

Avian influenza has killed at least 61 people in Vietnam, Thailand and Cambodia since early 2004, mostly farmers and poultry workers in close contact with the animals. Millions of birds have been slaughtered in Asia in an attempt to control the disease. The World Health Organization has warned that the viral strain affecting chickens, ducks and wild fowl could develop into a form that spreads easily among humans, exposing millions of people to the disease.

WHO reported Thursday that the spread of the H5N1 strain in Russia “is of concern because it creates further opportunities for human exposure.” Russian officials said there have been no human infections since the virus was detected in July 2005.

There are about 233 million head of poultry in commercial enterprises in Russia, according to the Russian Poultry Union. The spread of the disease into the industry would be economically devastating for the country and could affect neighboring countries, including those of the European Union.

Countries in the region and in the European Union have begun banning the importation of feathers and live birds from Russia.

“We are preparing for a worst-case scenario,” said Renate Kunast, Germany’s consumer protection minister, announcing emergency restrictions this month on poultry kept in the open. Free-range chicken is popular in Germany.

The Netherlands had already ordered poultry farmers to move their operations indoors to reduce the risk of exposure to wild birds and help contain any outbreak.

The British government is sending 50-page pamphlets to doctors with information on how to deal with any human outbreak, the Financial Times reported.

Russian officials said that if the presence of bird flu is confirmed at the Omsk farm, all the poultry there would be killed, according to Interfax.

About 11,000 birds have died of the disease in Russia and an additional 127,000 have been slaughtered on small farms, officials said. Up to 40 Russian villages have been hit by bird flu and 78 are under watch, according to the federal veterinarian and plant health oversight service.