Ge. Avellaneda et al., IN-VIVO EVALUATION OF THE PATHOGENICITY OF FIELD ISOLATES OF INFECTIOUS-BRONCHITIS VIRUS, Avian diseases, 38(3), 1994, pp. 589-597
The pathogenicity of 13 field isolates of infectious bronchitis virus
(IBV) isolated from Georgia broiler farms from 1989 to 1992 was evalua
ted using the IBV and Escherichia coli mixed-infection model. Based on
the clinical signs, mortality, and lesions, the isolates were classif
ied as high, intermediate, and low in pathogenicity. The in vivo class
ification was compared with the serotype classification results obtain
ed by reverse transcriptase-polymerase chain reaction-restriction frag
ment length polymorphism analysis. The high-pathogenicity group was co
mposed of five isolates representing three serotypes: Arkansas, Georgi
a variant (GAV), and Massachusetts. Isolates in the intermediate- and
low-pathogenicity groups were all representatives of the Connecticut s
erotype, except for one isolate, which belonged to the Massachusetts s
erotype.