Health officials fear a subtype of bird flu could mutate into a lethal strain and rival or exceed the Spanish flu pandemic, which killed between 20 to 40 million people worldwide at the end of World War I.
The presence of H5N1, which can cause the disease in humans, has so far only been confirmed in the Russian region of Novosibirsk, while four other Siberian regions have been confirmed to have some type of bird flu virus.
Russia's Agriculture ministry says the disease has been confirmed in wildfowl in two locations in the Kurgan region and one in the Omsk region. Bird flu has been confirmed in the Altai and Tyumen regions.
The statement says the virus found in Kurgan and Omsk does not appear to be highly pathogenic.
H5N1 has killed over 50 people in Asia since late 2003, most of them in Vietnam. Bird flu has also led to the death of 140 million birds, at a cost of billions of dollars.
Russia has culled over 10,000 domestic birds during the last few days in attempts to halt the virus' spread.
The ministry adds while no new deaths have occured among wild birds or domestic poultry in Altai, Tyumen and Omsk, 139 birds were found dead in the Novosibirsk region.
Meanwhile, senior veterinary officials in Kazakhstan confirm the break out of bird flu in the Pavlodar region, which borders Novosibirsk.
Officials indicate it is too early to say whether the Pavlodar outbreak is dangerous to humans, but a disease with similar symptons is killing birds in neighboring regions.
The Kazakh Emergencies Ministry says sanitary and veterinary controls are being increased to contain the spread of the disease. In Akmola, 70 hens and ducks living on private farm, which may have been in contact with wild ducks, have been destroyed.
