Effectiveness of Rose Bengal test and fluorescence polarization assay in the diagnosis of Brucella spp. infections in free range cattle reared in endemic areas in Zambia

Abstract

The effectiveness of Rose Bengal test (RBT) and fluorescence polarization assay (FPA) in diagnosing cattle brucellosis in endemic areas was assessed and RBT and FPA test agreement was compared (n = 319). The sensitivity of RBT and FPA in detecting low Brucella titres were evaluated in paired sera (n = 34). A logistic regression model was constructed to predict cattle test result in FPA using RBT as the main predictor and incorporating bio-data and animal history. There was 79.3% agreement between the RBT and FPA (Kappa = 0.59; Std error = 0.05; p = 0.000) and a high correspondence between high RBT scores and positive FPA results suggesting that sera with high RBT score may not require confirmation with tests such as competitive-ELISA or CFT. High FPA cut-off points were more likely to miss animals with low antibody titres. The RBT had a reduced ability in detecting low antibody titres compared to the FPA. FPA test interpretation was improved if a priori information, such as sex and age was used. Under the challenging disease surveillance conditions prevailing in rural Africa, field-testing methods that are sensitive and specific; allow single animal contact, low technical skills in data interpretation are suitable.

Evaluation of a Rapid Immunochromatographic Test for Detection of Brucella Abortus Antibodies in Egyptian Cattle Sera and Milk

“…culture and phenotypic characterization, are laborious, time-consuming, pose the risk of infection, and can generate discordant results (Muma et al, 2009). Serological tests are therefore commonly used for Brucella diagnosis in cattle and small ruminants especially at herd level.…”

Demyelinating steroid-responsive neurobrucellosis

“…WHO guidelines state that even if this test is positive, it needs further confirmation by other tests 16. Points of concern regarding use of Rose Bengal test by several authors include lower sensitivity and false negative test if the titre in serum is very high due to prozone phenomenon 15 17. Serum agglutinin test and enzyme-linked immune assay are the most commonly used methods.…”

Improvement in the diagnosis of Brucella abortus infections in naturally infected water buffaloes (Bubalus bubalis) using an ELISA with a Protein-G-based indicator system

“…Despite these drawbacks, the RBT remains to be a robust independent test because its performance is not dependent on secondary antibody, and therefore, its use as predictor test is justified (Alton et al 1988;Mainar-Jaime et al 2005). Moreover, the use of RBT as a predictor test in the recent studies in cattle (Muma et al 2009) and marine mammals (Hernandez-Mora et al 2009) advocates its effectiveness in the diagnosis of brucellosis in animals.…”