Evaluation of an indirect ELISA method for the detection of chicken antibodies against infectious bronchitis virus

An indirect ELISA method was developed and applied to detect antibodies against infectious bronchitis virus (IBV). Three hundred serum samples collected from vaccinated and non-vaccinated chickens under field conditions were tested. The ELISA results were compared with antibody titers determined by a serum neutralization assay (SN). Good coefficients of correlation (r(2)=0.750) and of agreement (80%) were recorded and the ELISA reproducibility was high. The cutoff point between those techniques corresponded to ELISA level 2. It is concluded that our indirect ELISA method can advantageously replace the conventional SN test, allowing a good follow-up of IBV post-vaccination antibodies due to its convenience and applicability compared to the other assay