Comparative evaluation of in vitro and in vivo assays for the detection of avian infectious bronchitis virus as a contaminant of live poultry vaccines

A reverse transcriptase polymerase chain reaction (RT-PCR) assay specific for identifying avian infectious bronchitis virus (IBV) in poultry vaccines, ind the serological response to IBV induced by the inoculation of chicks with a Newcastle disease vaccine spiked with the Massachusetts strain of IBV, were compared for their ability to detect IBV as a contaminant of avian vaccines. The sensitivity of the IBV-RT-PCR assay provided results which were at least equivalent to the biological effect produced by the inoculation of chicks, allowing this assay to be considered a valid alternative to animal testing in the quality control of avian immunologicals. This procedure can easily be adapted to detect a number of contaminants for which the in vivo test still represents the only available method of detection.