Evaluation of serological pseudorabies tests for the detection of antibodies during early infection

Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames 50011.

Six enzyme-linked immunosorbent assays, a latex agglutination test, and the standard microtitration serum virus neutralization test were compared for their ability to detect antibodies against pseudorabies virus (PRV) during the early stages of infection. Thirty-five pigs were infected intranasally with 10(5)-10(7) TCID50 of either the Iowa 4892 pneumotropic or the Becker strain of PRV. Blood samples were drawn from experimentally inoculated animals on days 4-10, 14, and 21 postchallenge. Test sensitivity estimates and comparisons among tests were made for each sampling day over the 21-day monitoring period. Results of this study demonstrated differences among tests in 1) the time from inoculation to initial antibody detection, 2) the time to detect > or = 95% of the infected pigs, and 3) the time from initial antibody detection to determination of > or = 95% as positive. By day 10 postchallenge, no statistically significant difference in diagnostic sensitivity was observed among the 8 tests compared in the study.