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


METHODS
391 cattle and 381 water buffalo.


METHODS
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
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.
Fosgate
Geoffrey T
GT
Department of Veterinary Anatomy, College of Veterinary Medicine, Texas A&M University, USA.
Adesiyun
Abiodun A
AA
Hird
David W
DW
Johnson
Wesley O
WO
Hietala
Sharon K
SK
Schurig
Gerhardt G
GG
Ryan
Joseph
J
D000372:Agglutination Tests / Q000379:methods / Q000662:veterinary*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001499:Bayes Theorem; D002003:Brucella abortus / Q000302:isolation & purification*; D002006:Brucellosis / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D002020:Buffaloes / Q000097:blood / Q000382:microbiology*; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000175:diagnosis / Q000382:microbiology*; D005260:Female; D012680:Sensitivity and Specificity; D014300:Trinidad and Tobago
D000907:Antibodies, Bacterial