通常与传染性支气管炎病毒，新城疫病毒和大肠杆菌等病原协同感染，导致呼吸道症状加剧，使死亡率增高。

Usually chickens suffered co-infection with Infectious bronchitis, Newcastle virus or Escherichia, and led to forced-breathing and increased mortality.

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通常与传染性支气管炎病毒，新城疫病毒和大肠杆菌等病原协同感染，导致呼吸道症状加剧，使死亡率增高。

Usually chickens suffered co-infection with Infectious bronchitis, Newcastle virus or Escherichia, and led to forced-breathing and increased mortality.

youdao