Detection of Mycobacterium bovis infection in African buffaloes (Syncerus caffer) using QuantiFERON®-TB Gold (QFT) tubes and the Qiagen cattletype® IFN-gamma ELISA

Netanya Bernitz; Charlene Clarke; Eduard O Roos; Wynand J Goosen; David Cooper; Paul D van Helden; Sven D C Parsons; Michele A Miller

doi:10.1016/j.vetimm.2017.12.010

Detection of Mycobacterium bovis infection in African buffaloes (Syncerus caffer) using QuantiFERON^®-TB Gold (QFT) tubes and the Qiagen cattletype^® IFN-gamma ELISA

Vet Immunol Immunopathol. 2018 Feb:196:48-52. doi: 10.1016/j.vetimm.2017.12.010. Epub 2017 Dec 22.

Authors

Netanya Bernitz¹, Charlene Clarke¹, Eduard O Roos¹, Wynand J Goosen¹, David Cooper², Paul D van Helden¹, Sven D C Parsons¹, Michele A Miller³

Affiliations

¹ DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/SAMRC Centre for TB Research/Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, PO Box 241, Cape Town 8000, South Africa.
² Ezemvelo KwaZulu-Natal Wildlife, PO Box 25, Mtubatuba, 3935, South Africa.
³ DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/SAMRC Centre for TB Research/Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, PO Box 241, Cape Town 8000, South Africa. Electronic address: miller@sun.ac.za.

PMID: 29695324
DOI: 10.1016/j.vetimm.2017.12.010

Abstract

African buffaloes (Syncerus caffer) are wildlife maintenance hosts of Mycobacterium bovis, the cause of bovine tuberculosis. Consequently, M. bovis infected buffaloes pose a transmission risk for cattle and other wildlife species. Previously, a modification to the Qiagen QuantiFERON^®-TB Gold (QFT) system, using QFT tubes and an in-house bovine interferon-gamma (IFN-γ) ELISA, was evaluated for the detection of M. bovis infection in buffaloes. Subsequently, Qiagen has developed a commercially available cattletype^® IFN-gamma ELISA for the detection of antigen-specific IFN-γ release in ruminants. The aim of this study was to investigate the use of QFT tubes and the cattletype^® IFN-gamma ELISA, in a cattletype IFN-γ release assay (IGRA), to detect M. bovis infection in African buffaloes. The test agreements between the cattletype IGRA, single comparative intradermal skin test (SCITT) and Bovigam^® 1G IGRA in two M. bovis-exposed buffalo populations (n = 134 and n = 92) were calculated and κ coefficients ranged from 0.65 (95% CI 0.48-0.82) to 0.86 (95% CI 0.72-0.99). Increasing the QFT incubation time in one M. bovis-exposed buffalo cohort (n = 92), from 20 to 40 h, had no effect on the cattletype IGRA test results. Inter-assay and intra-assay reproducibility determination for the cattletype IGRA produced coefficient of variations (CV) <9.1% and <1.7%, respectively. A total of 21/21 known M. bovis-unexposed buffaloes tested negative in the cattletype IGRA. Moreover, the cattletype IGRA test result values were significantly greater for 13 M. bovis culture-positive buffaloes compared with 14 M. bovis-exposed culture-negative (P < .01) and 21 M. bovis-unexposed (P < .001) buffaloes, respectively. These findings suggest that the combination of QFT tubes and the cattletype^® IFN-gamma ELISA is a promising new diagnostic assay for the detection of M. bovis infection in African buffaloes. However, further research is needed to evaluate the sensitivity and specificity of the assay in larger African buffalo populations.

Keywords: African buffalo; Bovine tuberculosis; Cattletype(®) IFN-gamma ELISA; Interferon gamma release assay; Mycobacterium bovis; QuantiFERON(®).

MeSH terms

Animals
Buffaloes / microbiology*
Enzyme-Linked Immunosorbent Assay / veterinary
Interferon-gamma Release Tests / veterinary*
Mycobacterium bovis*
Reproducibility of Results
Tuberculosis / diagnosis
Tuberculosis / microbiology
Tuberculosis / veterinary*