EVALUATION OF AVIDIN-BIOTIN ELISA FOR THE DETECTION OF ANTIBODIES TO GOAT POXVIRUS USING NONINFECTIOUS DIAGNOSTIC REAGENT

A noninfectious soluble antigen fraction of goat poxvirus (GPV) fractionated by ammonium sulfate precipitation was tested for its suitability as coating antigen in an indirect enzyme-linked immunosorbent assay (ELISA). Accordingly, an avidin-biotin ELISA for the detection of GPV antibodies was optimized and evaluated using different groups of serum samples from goats with known or unknown immune status. A cut-off value higher by 60% than A492 reading of control negative sera gave a 91.8% specificity and a 94.1% sensitivity for the assay. Out of 90 goat pox-suspect sera obtained from the field, only 2 (2.2%) were found positive in the counter immunoelectrophoresis (CIE) test, which is so far the routinely used diagnostic test for goat pox, while 58 (64.4%) were positive in the avidin-biotin ELISA. The McNemar’s analysis of these data showed that the avidinbiotin ELISA was significantly more efficient than the CIE test for the detection of GPV antibodies in goat sera.