Comparison of Interferon Gamma Release Assay and Gene Expression Assay for the Detection of Infection in African Lions ()

() infection has been identified in both domestic and wild animals and may threaten the conservation of vulnerable species including African lions (). There is a need to develop accurate ante-mortem tools for detection of infection in African big cat populations for wildlife management and disease surveillance. The aim of this study was to compare the performances of two immunological assays, the QuantiFERON-TB Gold Plus (QFT) Mabtech Cat interferon gamma release assay (IGRA) and QFT gene expression assay (GEA), which have both shown diagnostic potential for detection in African lions. Lion whole blood (n=47), stimulated using the QFT platform, was used for measuring antigen-specific expression and IFN-γ production and to assign infection status. A subset (n=12) of mycobacterial culture-confirmed infected and uninfected African lions was used to compare the agreement between the immunological diagnostic assays. There was no statistical difference between the proportions of test positive African lions tested by the QFT Mabtech Cat IGRA compared to the QFT GEA. There was also a moderate association between immunological diagnostic assays when numerical results were compared. The majority of lions had the same diagnostic outcome using the paired assays. Although the QFT Mabtech Cat IGRA provides a more standardized, commercially available, and cost-effective test compared to QFT GEA, using both assays to categorize infection status in lions will increase confidence in results.