Bacteriological Examination and Diagnostic Performance of Some Serological Tests Used In Diagnosis of Small Ruminant Brucellosis

Abdel-Mortada, Ola; Abdel-Hamid, Nour; Abdel Hady, Hemmat; Farouk, Rania

doi:10.21608/vmjg.2016.365334

Bacteriological Examination and Diagnostic Performance of Some Serological Tests Used In Diagnosis of Small Ruminant Brucellosis

Document Type : Original Article

Authors

¹ Microbiology Department, Faculty of Agriculture, Ain Shams University

² Department of Brucellosis Research Animal Health Research Institute, Nadi EL-Seid Street, Dokki, Giza 12618, Egypt

10.21608/vmjg.2016.365334

Abstract

A total of 249 serum samples was collected from 120 ewes and 129 goats from the Nile delta Governorates with no history of vaccination against brucellosis and with sporadic cases of late-term abortions. Collected serum samples were serologically examined for brucellosis using the screening tests; buffered acidified plate antigen (BAPA), modified Rose-Bengal (mRBT) and indirect enzyme linked immunosorbent assay (iIELISA). Also the supplementary micro-agglutination (MAT), EDTA modified micro-agglutination tests, as well as the confirmatory complement fixation (CFT) and Rivanol- precipitation plate agglutination tests (Riv. T) were used. The aim was to evaluate the diagnostic performance of these tests as regards to relative sensitivity/specificity, area under the receiver operating characteristic curve (AUC), diagnostic odds ratio (DOR) and kappa agreement (k) with complement fixation test (gold standard). Good diagnostic significance was proved with BAPA, mRBT and iELISA in the form of high relative sensitivities on the expense of relative specificities, substantial agreement with CFT, high DORs and better performance based on ROCs and AUCs. Questionable diagnostic results were recorded by MAT render it unreliable for diagnosis of small ruminant brucellosis. The diagnostic performance of Riv.T didn’t fulfil the requirements for the confirmatory test particularly in sheep where the test recorded the lowest relative sensitivity and specificity of 73% and fair agreement (0.224) with the CFT, lowest DOR (7.35)and AUC (0.8). These results subsequently reclassified the test as a supplementary rather than a confirmatory test. Bacteriological examination of samples from small ruminants resulted in the recovery of 9 isolates of Brucella melitensis biovar 3.

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