Pseudorabies virus (PRV) antibody detection in swine serum and oral fluid specimens

Authors: CHENG, TING-YU - Iowa State University; Buckley, Alexandra; VAN GEELEN, ALBERT - Animal And Plant Health Inspection Service (APHIS); Lager, Kelly; HENAO-DIAZ, ALEXANDRA - Iowa State University; POONSUK, KORAKRIT - Iowa State University; PINEYRO, PABLO - Iowa State University; JI, JU - Iowa State University; WANG, CHONG - Iowa State University; BAUM, DAVE - Iowa State University; MAIN, ROGER - Iowa State University; ZIMMERMAN, JEFF - Iowa State University; GIMENEZ-LIROLA, LUIS - Iowa State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/6/2019
Publication Date: 3/8/2020
Citation: Cheng, T., Buckley, A.C., Van Geelen, A., Lager, K.M., Henao-Diaz, A., Poonsuk, K., Pineyro, P., Ji, J., Wang, C., Baum, D., Main, R., Zimmerman, J., Gimenez-Lirola, L. 2020. Pseudorabies virus (PRV) antibody detection in swine serum and oral fluid specimens. American Association of Swine Veterinarians Annual Meeting. Atlanta, Georgia. March 7-10, 2020, p. 37.

Interpretive Summary:

Technical Abstract: OBJECTIVE:Evaluate PRV antibody detection in serum and oral fluid specimens using a commercial PRV whole virus indirect IgG ELISA kit (ADV(S), IDEXX Laboratories, Inc., Westbrook, ME). The ELISA was originally designed for serum antibody detection and adapted to the oral fluid matrix by the investigators. Serum and oral fluid samples of known PRV status were generated for assay validation and evaluation. METHODS:Oral fluid and serum samples were obtained from 12- to 16-week-old pigs allocated to in of 4 groups (10 pigs per group): 1) negative control (NC), 2) wild-type PRV inoculation (PRV 3CR Ossabaw), 3) PRV vaccination (MLV) (Ingelvac® Aujeszky MLV, Boehringer Ingelheim, Ridgefield, CT), and 4) PRV vaccination followed by PRV inoculation (PRV 3CR Ossabaw) at 21 days post vaccination. Depending on the group, serum and oral fluid samples were collected from individual animals for up to 62 days. Serum and oral fluid samples were tested for PRV antibody using a PRV whole virus indirect IgG ELISA; oral fluid samples were tested using a modified protocol. ROC curve and repeatability analyses were performed to evaluate assay performance. RESULTS:PRV antibody detection in serum and oral fluids specimens showed a similar pattern, with the exception that MLV induced very low levels of antibody in oral fluids. PRV antibody was detected in serum by 10 days post vaccination (MLV-PRV and MLV) or inoculation (PRV); in oral fluid by 14 days after inoculation (MLV-PRV and PRV). A rapid and strong anamnestic response was observed in Group 3 pigs, i.e., MLV followed by PRV inoculation. No serum or oral fluid antibodies were detected in the NC group. The area under ROC curves were calculated as 1.00 for serum and 0.94 for oral fluid. Intra-correlation coefficients (ICC) of serum and oral fluid testing were estimated at 99.04% and 99.34%. CONCLUSIONS:1) Detectable levels of PRV-specific antibodies are present in oral fluid specimens and 2) the temporal pattern of antibody detection induced by wild-type PRV was similar in oral fluids and serum. The commercial PRV indirect ELISA provided excellent binary diagnostic performance and a high degree of repeatability (greater than 99%). Research in progress will focus on the further optimization of the commercial PRV indirect ELISA for oral fluids.