Quantification of Teratological Effects of Infectious Bronchitis Virus Isolated from Commercial Poultry in Pakistan

Abstract

In continuation of our studies with the Infectious Bronchitis prevalence in Pakistan, the current study was conducted to determine the teratological effects of the Infectious Bronchitis Virus (IBV) on developing chicken embryo. The tissues collected (Trachea and Lungs) from clinically positive IB chickens were tested with the indirect immunofluorescence assay against M-41 IBV strain (reported previously). The positive samples were further tested with the RT-PCR against the IBV primers (reported previously). The tissue homogenates from 43 such RT-PCR-positive samples were serially passaged through 11 days old embryos and the effects on the embryonic development in terms of dwarfing, curling, stunting and urates deposits were recorded. The data showed that the passaging sequentially increased the IBV teratological effects. Only 13 out of 43 samples exhibited IBV-associated teratological effects over various passages. These effects were effectively neutralizes by using IBV variant specific antisera in a viral neutralization test. These studies imply that IBV variants isolated from Pakistan are no different in producing teratological effects considered representative of the IBV.