Russian health workers have found mass bird deaths in the region to the west of the Ural Mountains. It is feared this could signal the first case of the deadly bird flu virus spreading to Europe.The deaths occurred on a farm in the Caspian region of Kalmykia, although it is still unclear whether they were caused by bird flu. Russia has been fighting to contain an outbreak of avian flu since mid-July, when the first case of the disease — which can also kill humans — was registered thousands of kilometres away in Siberia. There have been no cases of the influenza among humans in Russia. At least 57 people have died from a type of the disease in Southeast Asia since 2003. Officials fear migrating birds could spread it to Western Europe, Africa and the Middle East over the coming months.