Bird flu: The global threat

H5N1, a highly pathogenic avian flu is racing across the world, and has infected multiple species, including wild and farmed birds, and mammals from cats to sea lions. What can be done to control it? Roland Pease talks to global experts about the dangers to animal and human health, and about the measures to bring the outbreak under control.Producer: Roland Pease Assistant producer: Sophie Ormiston(Photo: A government worker examines chicks for signs of bird flu infection at a poultry farm in Darul Imarah in Indonesia's Aceh province. Credit: Chaideer Mahyuddin)