The H5N1 avian flu was reported in wild ducks in four regions of Siberia, Russian agricultural officials reported Tuesday.

An unidentified official told the Itar-Tass news agency the outbreak appeared to affect only wild ducks, as there had been no positive reports of the virus in poultry.

"These birds either had contact with infected birds or carried the virus themselves to recover," the source said. "Forty-seven probes exposed genetic material of the virus and presence of antibodies in blood serum."

The report said 6 million domestic animals are considered to be at risk in the regions, although more than two-thirds of the birds have been vaccinated.

Copyright 2007 by United Press International