A rapid-plate hemagglutination assay for the detection of infectious bronchitis virus

A rapid-plate hemagglutination (HA) test to detect infectious bronchitis vi rus (IBV) in allantoic fluid of embryonated eggs was introduced into routin e procedures for IBV identification. This system was tested in 468 diagnost ic cases received by the Poultry Diagnostic and Research Center at the Univ ersity of Georgia. Allantoic fluids from inoculated embryos were harvested and treated with commercially available neuraminidase enzyme. IBV in neuram inidase-treated allantoic fluid was identified by clear and consistent HA o f chicken red blood cells within 1 min of incubation. The specificity of th e neuraminidase rapid-plate WA assay was examined with other avian viruses in individual and dual embryonic infections. Sensitivity of this test was c ompared with embryo lesions and reverse transcriptase-polymerase chain reac tion (RT-PCR). The rapid-plate HA assay of neuraminidase-treated allantoic fluid correlated with the RT-PCR during the early stages of IBV detection, identification, and isolation in embryonated eggs.