Characterization of Mexican strains of avian infectious bronchitis isolated during 1997

Ten infectious bronchitis virus (IBV) isolates were recovered from broiler chickens in the states of Queretaro and Guanajuato in Mexico. The viruses w ere isolated from trachea, lung, kidney, and cecal tonsils of birds that sh owed respiratory signs in spite of vaccination with Massachusetts (Mass) an d Connecticut strains of IBV. Each isolate was identified by an accession n umber from 1 to 10. Six of the isolates were neutralized by Mass monoclonal antibodies, whereas the other four were not. In addition, these four isola tes did not produce lesions in embryos in the first five to seven passes. T hese four isolates were further characterized by the reverse transcriprase- polymerase chain reaction and restriction fragment length polymorphism tech niques. The electrophoretic patterns for the four isolates were identical b ut were different from other known IBV isolates.