title: Modification of the QuantiFERON-TB Gold (In-Tube) assay for the diagnosis of Mycobacterium bovis infection in African buffaloes (Syncerus caffer).
abstract: African buffaloes (Syncerus caffer) are the most significant wildlife maintenance hosts of Mycobacterium bovis, the causative organism of bovine tuberculosis (BTB). Current diagnostic tests for the detection of M. bovis infection in free-ranging buffaloes have numerous limitations and we wished to evaluate a modification to a human TB assay, the QuantiFERON-TB Gold (In-Tube) assay (QFT), as a practical diagnostic test for BTB in buffaloes. One hundred and seventy-five buffaloes were tested using the single intradermal comparative tuberculin test (SICTT) and a modified QFT (mQFT). An appropriate cut-off point for the mQFT was derived from SICTT results using receiver operator characteristic curve analysis. Twenty-six SICTT-positive buffaloes were killed and subjected to necropsy, and selected tissues were processed for mycobacterial culture and speciation. An optimal cut-off point for the mQFT was calculated as 66pg/ml. The assay correctly detected 39/40 SICTT-positive buffaloes and 129/134 TST-negative buffaloes and M. bovis was cultured from 21/26 slaughtered SICTT/mQFT-positive animals. The mQFT shows promise as a practical test for M. bovis infection in buffaloes and shows a sensitivity and specificity at least similar to that of the TST.
authors.affiliation: DST/NRF Centre of Excellence for Biomedical TB Research/MRC Centre for Molecular and Cellular/Biology, Division of Molecular Biology and Human Genetics, Faculty of Health Sciences, Stellenbosch University, P.O. Box 19063, Tygerberg 7505, South Africa. sparsons@sun.ac.za
authors.forename: Sven D C
authors.initials: SD
authors.lastname: Parsons
authors.forename: David
authors.initials: D
authors.lastname: Cooper
authors.forename: Alicia J
authors.initials: AJ
authors.lastname: McCall
authors.forename: Warren A
authors.initials: WA
authors.lastname: McCall
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Streicher
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: le Maitre
authors.forename: Annélle
authors.initials: A
authors.lastname: Müller
authors.forename: Nicolaas C
authors.initials: NC
authors.lastname: Gey van Pittius
authors.forename: Robin M
authors.initials: RM
authors.lastname: Warren
authors.forename: Paul D
authors.initials: PD
authors.lastname: van Helden
mesh_terms: D000818:Animals; D002020:Buffaloes / Q000276:immunology / Q000382:microbiology*; D007371:Interferon-gamma / Q000502:physiology; D009163:Mycobacterium bovis; D011933:Reagent Kits, Diagnostic / Q000662:veterinary; D012680:Sensitivity and Specificity; D014374:Tuberculin Test / Q000662:veterinary; D014376:Tuberculosis / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*
chemical_list: D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma