Evaluation of three serological tests for brucellosis in naturally infected cattle using latent class analysis
Department of Disease Control, University of Zambia, School of Veterinary Medicine, P.O. Box 32379, Lusaka, Zambia; Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep, 0033 Oslo, Norway; Department of Large Animal Sciences, The Royal Veterinary and Agricultural University, Groennegaardsvej 8, DK-1870 Frederiksberg C., Denmark; Department of Veterinary Public Health and Preventive Medicine, Makerere University, P.O. Box 70062, Kampala, Uganda; National Veterinary Institute, P.O. Box 8156 Dep, N-0033 Oslo, Norway; Animal Disease Research Institute, Canada Food Inspection Agency, 3851 Fallowfield Road, Nepean, Ont. K2H 8P9, Canada
Serological methods are traditionally used in diagnosis of brucellosis. However, the comparative performance of these tests and their accuracy under the local environment in Zambia has not been assessed. Thus, the objective of our study was to evaluate the diagnostic performance of three serological tests for brucellosis; Rose Bengal Test (RBT), competitive ELISA (c-ELISA) and Fluorescence Polarisation Assay (FPA) in naturally infected cattle in Zambia without an appropriate reference test to classify animals into truly infected and non-infected. Serological test results from a study to determine sero-prevalence were used to compare the performance of RBT, c-ELISA and FPA in diagnosing brucellosis in traditional cattle. Since none of the tests can be seen as a perfect reference test or gold standard, their performance in a population of naturally infected cattle was evaluated using latent class analysis which allows the sensitivity (Se) and specificity (Sp) to be estimated in the absence of a gold standard. The highest Se was achieved by the c-ELISA (97%; Credible Posterior Interval (CPI) = 93-100%) and the highest Sp by the FPA (93%; CPI = 85-99%), conversely these tests also had the lowest Sp and Se, respectively, with the RBT performing well in both the Se (93%; CPI = 84-98%) and Sp (81%; CPI = 61-97). © 2007 Elsevier B.V. All rights reserved.
rose bengal; article; brucellosis; cattle disease; enzyme linked immunosorbent assay; fluorescence polarization immunoassay; gold standard; nonhuman; sensitivity and specificity; serodiagnosis; serology; seroprevalence; Zambia; Agglutination Tests; Animals; Antibodies, Bacterial; Bayes Theorem; Brucella; Brucellosis, Bovine; Cattle; Enzyme-Linked Immunosorbent Assay; Fluorescence Polarization Immunoassay; Rose Bengal; Sensitivity and Specificity; Animalia; Bos