More importantly, this live attenuatedvirus provided effective protection when it was administered to birds before they had hatched.
更重要的是，这种减毒活病毒结种于未孵化的鸟类后可提供有效的预防。
2
The virus was analyzed by the animal pathogenicity test, virus attenuation, protection of the attenuatedvirus and virulence return experiment.
对分离的痘病毒进行动物致病性试验、病毒分离传代和致弱试验、致弱毒保护力试验和返强试验。
3
Most will be inactivated virus vaccines made in eggs, some will be killed virus vaccines made in cell cultures and a few will be live attenuatedvirus vaccines.