Use of chemiluminescence for the serological diagnosis of bovine and ovine brucellosis with indirect and competitive enzyme-linked immunosorbent assays.
The official methods specified in the national bovine and ovine/caprine brucellosis eradication plan are the Rose Bengal and complement fixation tests. In the current phase of the eradication plan, it is often difficult to interpret the results obtained with the official tests. Consequently, additional tests that offer greater sensitivity and specificity are thus required. For this reason, two methods, the indirect chemiluminescence enzyme-linked immunosorbent assay (i-ELISA CL) and the competitive chemiluminescence ELISA (c-ELISA CL) that use a chemiluminescent substrate to determine anti-Brucella antibodies in bovine and ovine serum were validated. The methods are based on the detection of anti-Brucella antibodies in serum by catalysis of a chemiluminescent enzyme substrate (luminol/H2O2/enhancer system) by peroxidase conjugated to secondary anti IgG antibodies in i-ELISA CL and to monoclonal anti-lipopolysaccharide (LPS) antibodies in c-ELISA CL. From the results obtained, a cut-off of 60% for bovine serum and 37.5% for ovine serum, expressed as positivity rate (PR), were established using these cut-off values, for the i-ELISA CL, 100% sensitivity and specificity was obtained for bovine serum and 100% sensitivity and 99.8% specificity for ovine serum. Cut-off values of 30% for bovine serum and 40% for ovine serum, expressed as inhibition rate, were selected for c-ELISA CL, which ensured 100% sensitivity and specificity in both cases.
Tittarelli
Manuela
M
Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise G. Caporale, Via Campo Boario, Teramo, Italy. m.tittarelli@izs.it
Bonfini
Barbara
B
Salini
Romolo
R
Magliulo
Maria
M
Guardigli
Massimo
M
Roda
Aldo
A