Comparison of serologic tests for detection of Brucella infections in cattle and water buffalo (Bubalus bubalis)

• Published in: American journal of veterinary research Vol. 63; no. 11; pp. 1598 - 1605
• Main Authors: Fosgate, Geoffrey T, Adesiyun, Abiodun A, Hird, David W, Johnson, Wesley O, Hietala, Sharon K, Schurig, Gerhardt G, Ryan, Joseph
• Format: Journal Article
• Language: English
• Published: United States 01-11-2002
• Subjects: agglutination tests; Agglutination Tests - methods; Agglutination Tests - veterinary; Animals; antibodies; Antibodies, Bacterial - blood; Bayes Theorem; blood serum; Brucella; Brucella abortus - isolation & purification; brucellosis; Brucellosis - blood; Brucellosis - diagnosis; Brucellosis - microbiology; buffaloes; Buffaloes - blood; Buffaloes - microbiology; Cattle; Cattle Diseases - blood; Cattle Diseases - diagnosis; Cattle Diseases - microbiology; diagnostic specificity; diagnostic techniques; Female; herds; probability; screening; Sensitivity and Specificity; Trinidad and Tobago; Trinidad and Tobago
• ISSN: 0002-9645; 1943-5681
• DOI: 10.2460/ajvr.2002.63.1598

Objective-To estimate sensitivity and specificity of 4 commonly used brucellosis screening tests in cattle and domestic water buffalo of Trinidad, and to compare test parameter estimates between cattle and water buffalo. Animals-391 cattle and 381 water buffalo. Procedure-4 Brucella-infected herds (2 cattle and 2 water buffalo) and 4 herds (2 of each species) considered to be brucellosis-free were selected. A minimum of 100 animals, or all animals > 1 year of age, were tested from each herd. Serum samples were evaluated for Brucella-specific antibodies by use of standard plate agglutination test (SPAT), card test (CT), buffered plate agglutination test (BPAT), and standard tube agglutination test (STAT). A Bayesian approach was used to estimate sensitivity and specificity of diagnostic tests without the use of a gold standard, assuming conditional independence of tests. Results-Sensitivity and specificity estimates in cattle, respectively, were SPAT, 66.7 and 98.9; CT, 72.7 and 99.6; BPAT, 88.1 and 98.1; and STAT, 80.2 and 99.3. Corresponding test estimates in water buffalo, respectively, were SPAT, 51.4 and 99.3; CT, 90.4 and 99.4; BPAT, 96.3 and 90.7; and STAT, 75.0 and 98.8. Sensitivity of the CT and specificity of the BPAT were different between cattle and water buffalo with at least 95% probability. Conclusions and Clinical Relevance-Brucellosis serologic test performance varied by species tested, but BPAT had the highest sensitivity for screening cattle and water buffalo. Sensitivity and specificity of more than 2 screening tests can be estimated simultaneously without a gold standard by use of Bayesian techniques.