Clarke, C.; Bernitz, N.; Goosen, W.J.; Miller, M.A. High-Specificity Test Algorithm for Bovine Tuberculosis Diagnosis in African buffalo (Syncerus caffer) Herds. Pathogens2022, 11, 1393.
Clarke, C.; Bernitz, N.; Goosen, W.J.; Miller, M.A. High-Specificity Test Algorithm for Bovine Tuberculosis Diagnosis in African buffalo (Syncerus caffer) Herds. Pathogens 2022, 11, 1393.
Clarke, C.; Bernitz, N.; Goosen, W.J.; Miller, M.A. High-Specificity Test Algorithm for Bovine Tuberculosis Diagnosis in African buffalo (Syncerus caffer) Herds. Pathogens2022, 11, 1393.
Clarke, C.; Bernitz, N.; Goosen, W.J.; Miller, M.A. High-Specificity Test Algorithm for Bovine Tuberculosis Diagnosis in African buffalo (Syncerus caffer) Herds. Pathogens 2022, 11, 1393.
Abstract
Ante-mortem bovine tuberculosis (bTB) tests for buffaloes include the single comparative intradermal tuberculin test (SCITT), interferon-gamma (IFN-γ) release assay (IGRA) and IFN-γ-inducible protein 10 release assay (IPRA). Although parallel test interpretation increases detection of Mycobacterium bovis-infected buffaloes, these algorithms may not be suitable for screening buffaloes in historically bTB-free herds. In this study, the specificities of three assays were determined using M. bovis unexposed herds, and a high specificity diagnostic algorithm developed. Serial test interpretation using the IGRA and IPRA showed significantly greater specificity (98.3%) than individual tests or parallel testing (73%). When the SCITT was added, the algorithm had a 100% specificity. Since the cytokine assays had imperfect specificity, potential cross-reactivity with nontuberculous mycobacteria (NTM) was investigated. No association was found between NTM presence (in oronasal swab cultures) and positive cytokine assay results. As a proof-of-principle, serial testing was applied to high-value buffaloes (n=153) in a historically bTB-free herd. Buffaloes positive on a single test (n=28) were regarded as test negative. Four buffaloes were positive on IGRA and IPRA, and M. bovis infection was confirmed following culling. These results demonstrate the value of using IGRA and IPRA in series to screen buffalo herds with no previous history of M. bovis infection.
Keywords
African buffaloes; bovine tuberculosis; IGRA; IP-10 release assay; M. bovis; nontuberculous mycobacteria; serial testing; specificity; Syncerus caffer
Subject
Biology and Life Sciences, Biochemistry and Molecular Biology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
