The US Department of Agriculture has granted a conditional approval for Zoetis $ZTS to use its avian influenza vaccine for domestic poultry. This decision, based on solid safety data and justified expectations regarding efficacy, comes at a time when almost 70 human cases of avian influenza have been reported in the United States since last April, with one fatality. The majority of these cases involved farm workers with direct contact with infected domestic poultry or cattle.