Improving the sensitivity of the IBR-gE ELISA for testing IBR marker vaccinated cows from bulk milk.
The low sensitivity of the IBR-gE ELISA compared to other diagnostic ELISA tests for IBR is a major disadvantage of IBR control programmes based on IBR marker vaccination. Therefore the IBR-gE ELISA is not generally recommended for testing pooled or bulk milk samples.The aim of this study was to determine the performance of a commercially available kit for concentrating and purifying antibodies in milk in order to improve the sensitivity of detecting IBR-gE antibody positive cows from pooled and bulk milk samples. A single IBR-gE positive cow is likely to remain undetected in a pool of 49 negative milk samples without concentration. By contrast, the bulk milk concentration procedure improved sensitivity from 5.4% to 75.7% in a positive herd. Milk samples with a high or moderate positive signal are more likely to be detected after pool milk concentration compared to weak positive samples. Whereas a follow up study involving a monthly testing of bulk milk samples from three marker vaccinated IBR-gE negative herds over a period of seven months yielded negative results each month, bulk milk from a herd containing <5% IBR-gE positive cows always detected positive after concentration. Although the milk concentration procedure had no impact on specificity, it significantly enhanced the sensitivity of the detection of IBR-gE positive milk in pooled and bulk milk samples. After further evaluation this procedure could allow a cost efficient and reliable method of monitoring IBR marker-vaccinated herds for IBR-gE antibodies.
Labor Diagnostik GmbH Leipzig, Leipzig, Germany. cs@lab-leipzig.de
Carsten
C
Schroeder
Steffen
S
Horner
Nicole
N
Bürger
Claudia
C
Engemann
Ulrike
U
Bange
Eva V
EV
Knoop
Jörg
J
Gabert
D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis*; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000592:standards / Q000662:veterinary*; D005260:Female; D007242:Herpesvirus 1, Bovine / Q000276:immunology*; D022283:Herpesvirus Vaccines / Q000276:immunology; D007074:Immunoglobulin G / Q000032:analysis; D007241:Infectious Bovine Rhinotracheitis / Q000276:immunology* / Q000517:prevention & control*; D008892:Milk / Q000276:immunology*; D012680:Sensitivity and Specificity; D022581:Vaccines, Marker / Q000276:immunology; D014764:Viral Proteins / Q000276:immunology
D000914:Antibodies, Viral; D022283:Herpesvirus Vaccines; D007074:Immunoglobulin G; D022581:Vaccines, Marker; D014764:Viral Proteins; C046998:bovine herpesvirus type-1 glycoproteins