Serologic and Immunologic Properties of a Recent Isolate of Infectious Bronchitis Virus

In 1956, Jungherr et al. (9) described the immunological differences between 2 strains of infectious bronchitis virus (IBV) and proposed that they be designated the Massachusetts and Connecticut types. For some time thereafter, they were accepted as the only immunological types of IBV. Recently, other virus types have been described. Hofstad (7) reported Iowa 97 and 609, and Winterfield and Hitchner (15) later described the Gray and Holte types. In 1964, Winterfield et al. (16) described the JMK isolate as immunologically distinct from the above types. The Australian T strain and IBV-10 (Cuxhaven) have been compared by von Bulow (14) and reported as separate serotypes, while IBV-7 (Stuttgart) was a variant of the Massachusetts type. Purchase et al. (12) isolated RPL-IBV from a closed flock and reported it to be related to Iowa 97. Thus, in 11 years as many as 11 serotypes or variants of IBV have been described. In 1967 infectious bronchitis virus was isolated from chickens in a closed flock at the Southeast Poultry Research Laboratory. This report describes the isolate as a distinct serotype of IBV.