Parsons D, Ellis M M, Cavanagh D, Cook J K
AFRC Institute for Animal Health, Houghton Laboratory, Huntingdon.
Vet Rec. 1992 Oct 31;131(18):408-11. doi: 10.1136/vr.131.18.408.
Four apparently serologically closely related isolates of infectious bronchitis virus were obtained from two flocks of vaccinated broiler breeders, one mile apart, which were experiencing increased mortality and decreases in egg production. The isolates were serologically distinct from isolates previously described and capable of causing characteristic infectious bronchitis-like respiratory infection in young chicks. In one experiment, the H120 vaccine strain of the virus did not protect the trachea against challenge with the new isolates 21 days later.
从相距一英里的两个接种过疫苗的肉种鸡群中获得了四株在血清学上明显密切相关的传染性支气管炎病毒分离株，这两个鸡群当时正经历死亡率上升和产蛋量下降的情况。这些分离株在血清学上与先前描述的分离株不同，并且能够在幼雏中引起典型的传染性支气管炎样呼吸道感染。在一项实验中，该病毒的H120疫苗株在21天后不能保护气管免受新分离株的攻击。
