Development of a Gene Expression Assay for the Diagnosis of Mycobacterium bovis Infection in African Lions (Panthera leo). Issue 3 (30th October 2015)

• Record Type: Journal Article
• Authors: Olivier, T. T.; Viljoen, I. M.; Hofmeyr, J.; Hausler, G. A.; Goosen, W. J.; Tordiffe, A. S. W.; Buss, P.; Loxton, A. G.; Warren, R. M.; Miller, M. A.; van Helden, P. D.; Parsons, S. D. C.
• Is Part Of: Transboundary and emerging diseases. Volume 64:Issue 3(2017)
• Page Start: 774
• Page End: 781
• Publication Date: 2015-10-30
• Subjects: African lion -- diagnosis -- Mycobacterium bovis -- Panthera leo -- tuberculosis -- wildlife; Veterinary medicine -- Periodicals; 636.089
• DOI: 10.1111/tbed.12436
• Languages: English
• ISSNs: 1865-1674

Abstract

Summary: Mycobacterium bovis infection, the cause of bovine tuberculosis (BTB), is endemic in wildlife in the Kruger National Park (KNP), South Africa. In lions, a high infection prevalence and BTB mortalities have been documented in the KNP; however, the ecological consequences of this disease are currently unknown. Sensitive assays for the detection of this infection in this species are therefore required. Blood from M. bovis ‐exposed, M. bovis ‐unexposed, M. tuberculosis ‐exposed and M. bovis ‐infected lions was incubated in QuantiFERON ® ‐TB Gold (QFT) tubes containing either saline or ESAT‐6/CFP‐10 peptides. Using qPCR, selected reference genes were evaluated for expression stability in these samples and selected target genes were evaluated as markers of antigen‐dependent immune activation. The abundance of monokine induced by gamma interferon (MIG /CXCL9 ) mRNA, measured in relation to that of YWHAZ, was used as a marker of ESAT‐6/CFP‐10 sensitization. The gene expression assay results were compared between lion groups, and lenient and stringent diagnostic cut‐off values were calculated. This CXCL9 gene expression assay combines a highly specific stimulation platform with a sensitive diagnostic marker that allows for discrimination between M. bovis ‐infected and M. bovis ‐uninfected lions.