A study of cattle infected with Brucella abortus and which showed aberrant serological reactions

Abstract

Sixty cows, 48 of which had been vaccinated with live Brucella abortus strain 19 (S19) or with killed B. abortus strain 45/20 (S45/20) and 12 of which were unvaccinated animals, were challenged with B. abortus strain 544. Ten of the 27 cattle found to be infected after challenge showed aberrant serological reactions to the Rose Bengal Plate test, serum agglutination test and/or complement fixation test. These 10 cattle were all previously vaccinated with S19 or S45/20. It was concluded that infection in cattle vaccinated with S19 or S45/20 may be more difficult to detect than infection in animals that have no history of vaccination.

Comparison of enzyme-linked immunosorbent assay and complement fixation test for the detection of specific antibody in cattle vaccinated and challenged with Brucella abortus

“…First, the CFT often shows anticomplementary reactions as well as prozones where immunoglobulin G2 (IgG2) antibodies to B. abortus block IgG1 and IgM antibodies (11). Second, some infected cattle may show aberrant serological reactions and are not detected (7,15). Third, maternally infected cattle may be difficult to differentiate from those recently vaccinated with either of the above vaccines (8,16).…”