title: Diagnostic gap in Bovine viral diarrhea virus serology during the periparturient period in cattle.
abstract: Detection of antibodies against Bovine viral diarrhea virus (BVDV) in serum and milk by enzyme-linked immunosorbent assay (ELISA) is a crucial part of all ongoing national schemes to eradicate this important cattle pathogen. Serum and milk are regarded as equally suited for antibody measurement. However, when retesting a seropositive cow 1 day after calving, the serum was negative in 6 out of 9 different ELISAs. To further investigate this diagnostic gap around parturition, pre- and postcalving serum and milk samples of 5 cows were analyzed by BVDV antibody ELISA and serum neutralization test (SNT). By ELISA, 3 out of the 5 animals showed a diagnostic gap in the serum for up to 12 days around calving but all animals remained positive in SNT. In milk, the ELISA was strongly positive after birth but antibody levels decreased considerably within the next few days. Because of the immunoglobulin G (IgG)1-specific transport of serum antibodies into the mammary gland for colostrum production, the IgG subclass specificity of the total and the BVDV-specific antibodies were determined. Although all 5 animals showed a clear decrease in the total and BVDV-specific IgG1 antibody levels at parturition, the precalving IgG1-to-IgG2 ratios of the BVDV-specific antibodies were considerably lower in animals that showed the diagnostic gap. Results showed that BVDV seropositive cows may become "false" negative in several ELISAs in the periparturient period and suggest that the occurrence of this diagnostic gap is influenced by the BVDV-specific IgG subclass response of the individual animal.
authors.affiliation: 1Claudia Bachofen, Institute of Veterinary Virology, University of Bern, Länggassstraße 122, PO Box 8466, CH-3001 Bern, Switzerland. c.bachofen@gmx.net.
authors.forename: Claudia
authors.initials: C
authors.lastname: Bachofen
authors.forename: Barbara
authors.initials: B
authors.lastname: Bollinger
authors.forename: Ernst
authors.initials: E
authors.lastname: Peterhans
authors.forename: Hanspeter
authors.initials: H
authors.lastname: Stalder
authors.forename: Matthias
authors.initials: M
authors.lastname: Schweizer
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000097:blood / Q000276:immunology* / Q000821:virology; D002417:Cattle; D001908:Diarrhea Viruses, Bovine Viral / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D007074:Immunoglobulin G / Q000097:blood*; D007700:Kinetics; D008892:Milk / Q000276:immunology*; D009500:Neutralization Tests / Q000662:veterinary; D058725:Peripartum Period; D011247:Pregnancy
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G
keywords: Bovine viral diarrhea virus; calving; colostrum; diagnostic gap; enzyme-linked immunosorbent assay; periparturient period; serology