Russia said Saturday its scientists had detected the first case of transmission of the H5N8 strain of avian flu to humans and had alerted the World Health Organization.

"Information about the world's first case of transmission of the avian flu (H5N8) to humans has already been sent to the World Health Organization," the head of Russia's health watchdog Rospotrebnadzor, Anna Popova, said in televised remarks.

The highly contagious strain is lethal for birds but has never before been reported to have spread to humans.

Popova said that scientists at Russia's Vektor laboratory had isolated genetic material of the strain from seven workers of a poultry farm in southern Russia, where an outbreak was recorded among the birds in December.

The workers did not suffer any serious health consequences, she added.

Popova praised "the important scientific discovery," saying "time will tell" if the virus can further mutate.

"The discovery of these mutations when the virus has not still acquired an ability to transmit from human to human gives us all, the entire world, time to prepare for possible mutations and react in an adequate and timely fashion," Popova said.

Located in Koltsovo outside the Siberian city of Novosibirsk, the Vektor State Virology and Biotechnology Center has developed one of Russia's several coronavirus vaccines. 

In the Soviet era the top-secret lab conducted secret biological weapons research and still stockpiles viruses ranging from Ebola to smallpox.