MOSCOW -- The dangerous strain of bird flu known as H5N1 has killed nearly half a million domestic fowl in southern Russia in the past month despite efforts to control the outbreak by culling poultry, the Emergency Situations Ministry said yesterday.
About 495,000 birds near the Caspian and Black seas have died since Feb. 3 from the virulent strain of bird flu, which can also infect humans, said a ministry spokesman, Viktor Beltsov. Another 220,000 birds were killed in an attempt to stem the outbreak, he said.
This is the third large outbreak of the H5N1 strain of bird flu in Russia, but the previous episodes involved fewer deaths of sick birds. Last summer, about 17,000 birds died of the flu strain while more than 600,000 others were killed in an effort to prevent the disease's spread, according to the ministry. During a second outbreak from October to January, about 1,500 birds died of the disease and 6,500 were culled.
Health officials fear that the disease might mutate into a form that could be easily transmitted from person to person, possibly triggering a worldwide flu pandemic.
The disease is not spread to humans through birds that have been properly cooked.
Since 2003, 173 people in seven countries have contracted the virus and 93 of them have died, according to a World Health Organization tally as of yesterday. The first deaths were recorded in 1997 in Hong Kong. No cases of bird flu in humans have been detected in Russia.
Southern Russia is particularly vulnerable to the disease because it is a major stopover point for migratory birds, which have been blamed for spreading the H5N1 strain. The most severe outbreak has been in Dagestan, on the Caspian Sea, where 595,000 birds have died of flu or been culled.
The Dagestan outbreak began with the death of wild swans and was spread by crows and seagulls that fed on their carcasses, Zaidin Dzhambulatov, chairman of the regional government's veterinary committee, said in a telephone interview.
"Both the crows and the gulls fly all around, and in effect what we got was a rainfall of infected bird droppings," he said.
At two major poultry farms, wild birds got into the main feed preparation facilities, infecting grain that was then fed to poultry, he said.
Russia will begin mass vaccination of domestic fowl against bird flu starting March 10, Russian Agriculture Minister Alexei Gordeyev said yesterday. The country already has enough vaccine, he said in an interview with Mayak radio. He also predicted that migratory birds would carry the bird flu strain to the United States this spring.
The H5N1 strain of bird flu crossed into Western Europe for the first time in mid-February. By late in the month it had ravaged a farm of more than 11,000 turkeys at Versailleux, in southeastern France.
It is not yet clear how great a danger to human health may be posed by the spread of the disease in Russian poultry farms, said Svetlana Yatsyshina, head of the virus studies group at the Russian Health Ministry's Central Scientific Research Institute of Epidemiology.
"The likelihood of human infection depends on the closeness of people's contact with sick birds," she said. "If it is as close as it was in some of the Asian countries, when sick animals can be in the same room as people, that ratchets up the chances of human infection."
Viktor Maleyev, deputy director of the research institute, said that so far the worst impact from bird flu in Russia is economic.
"It's understandable that people might be upset about killing off domestic fowl," he said. "They might hope the birds aren't that sick. All of this costs money. ... The costs include compensation, special gear and disinfection work. There's restriction of movement, alarm."
David Holley writes for the Los Angeles Times.