Detection of antibodies against infectious bursal disease virus, infectious bronchitis virus, Newcastle disease virus, and M. gallisepticum

Blood serum samples were tested for detection of antibodies to IBDV, IBV, NDV, and MG by using an IDEXX Enzyme-linked Immunosorbent Assay (ELISA). Laboratory tests were conducted at the University of Georgia’s Poultry Diagnostic and Research Center in Athens, Georgia. Samples were classified as seropositive or seronegative to each pathogen of interest using antibody concentration cut-off points (i.e., IBVD S/P ratio = 0.50; IBV S/P ratio = 0.20; NDV S/P ratio = 0.20; MG S/P ratio = 0.20) recommended by the manufacturer (IDEXX IBD Ab Test Validation Data Report; IDEXX IBV Ab Test Validation Data Report IDEXX NDV Ab Test Validation Data Report; IDEXX MG Ab Test Validation Data Report). Using the HI test as gold standard, the relative sensitivity of the four tests = 100% in 10, 8, 11, and 30 experimentally vaccinated chickens, respectively. Similarly, the relative specificity of the four tests = 100% in 45, 45, 31, and 30 specific pathogen free chickens, respectively.