At least 150 domestic birds have died in suburban Moscow districts where the H5N1 bird flu strain was detected in the first outbreak close to the Russian capital, officials said Monday. Russia's Emergency Situations Ministry said disinfection and quarantine measures were being carried out in five districts where poultry deaths were reported. The presence of H5N1 so far has been confirmed in two of them, it said in a statement. The bird flu cases have been traced to a single animal market just outside Moscow city limits, said Alexei Alexeyenko, a spokesman for the federal agricultural oversight agency Rosselkhoznadzor. He said the strain that sickened birds near Moscow was of a highly virulent subtype and could have originated in Asia, the Caucasus region or the Balkans. "The strain is very dangerous and can affect humans," Alexeyenko said. He said poultry that died belonged to private individuals who had bought birds recently, and that the birds had not been vaccinated during preventive inoculation campaigns.