Development and evaluation of an indirect enzyme immunoassay for detection of porcine antibodies to pseudorabies virus.

An indirect enzyme immunoassay is described for detection of porcine serum antibody to pseudorabies virus. The analytical sensitivity of the enzyme immunoassay was found to be approximately 4.5 log 4 X 10 (5120 times) greater than the serum neutralization test, based on parallel end point titrations. The diagnostic sensitivity of the enzyme immunoassay was comparable or superior to that of the serum neutralization, based on the earliest detectable antibody after infection of swine with pseudorabies virus by intranasal or intrauterine routes or by contact with infected pigs. The enzyme immunoassay, at a screening dilution of 1:20, gave 100% agreement with ELISA results provided with a U.S. Department of Agriculture-Animal and Plant Health Inspection Service proficiency panel of 40 sera. One serum having demonstrable antibody by the enzyme immunoassay was seronegative by the serum neutralization test.