Bulgarian authorities are testing three birds found dead in the north of the country for avian flu. So far there are no indications that the deadly virus has crossed its borders. The tests were a result of stricter controls. Romania and Turkey, which border Bulgaria, reported new cases of the virus on Saturday. They will continue culling poultry to prevent the disease from spreading.UN co-ordinator for Avian and Human Influenza David Nabarro warned about the lack of vaccines currently available. “To prevent a pandemic of human influenza we have to intensify the global response to the current epidemic of avian influenza. We cannot be sure that existing vaccines that have been stored up would be effective,” he said. A meeting of European health ministers is due to take place October 20 and 21 at which they will outline a common strategy on the issue. If the Romanian cases turn out to be the H5N1 strain, it will be the first time that the virus has spread to Europe.