title: Rapid screening for Mycobacterium tuberculosis complex in clinical elephant trunk wash samples.
abstract: Mycobacterium tuberculosis can infect and be transmitted between elephants and humans. In elephants, the 'gold standard' reference test for detection of tuberculosis is culture, which takes a minimum of eight weeks for results and has limited sensitivity. A screening test that is rapid, easily implemented, and accurate is needed to aid in diagnosis of tuberculosis in elephants. Ninety-nine clinical trunk wash samples obtained from 33 elephants were utilized to validate three molecular extraction techniques followed by a polymerase chain reaction for detection of M. tuberculosis. Diagnostic sensitivity and specificity were estimated compared to culture. Kappa coefficients were determined between molecular results and various culture categories and serological test results. An internal amplification control was developed and assessed to monitor for PCR inhibition. One molecular test (the Column method) outperformed the other two, with diagnostic sensitivity and kappa agreement estimates of 100% (CI 57-100) and 0.46 (CI 0.2-0.74), respectively, compared to culture alone. The percentage of molecular-positive/culture-negative samples was 8.4% overall. The molecular extraction technique followed by PCR provides a much-needed rapid screening tool for detection of tuberculosis in elephants. Immediate procedures can be implemented to further assess PCR-positive animals and provide personnel biosecurity. While a positive result is not a definitive test for elephant tuberculosis, the molecular test results can be used to support current diagnostic procedures applied by veterinarians for treatment decisions to prevent the spread of tuberculosis in elephants.
authors.affiliation: Animal Population Health Institute, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Science, Colorado State University, 300 W. Drake Road, Fort Collins, CO 80525, USA. Electronic address: Roberta.Magnuson@colostate.edu.
authors.forename: Roberta J
authors.initials: RJ
authors.lastname: Magnuson
authors.affiliation: Animal Population Health Institute, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Science, Colorado State University, 300 W. Drake Road, Fort Collins, CO 80525, USA.
authors.forename: Lyndsey M
authors.initials: LM
authors.lastname: Linke
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO Box 100126, 2015 SW 16th Ave. Gainesville, FL 32610-0126, USA.
authors.forename: Ramiro
authors.initials: R
authors.lastname: Isaza
authors.affiliation: Animal Population Health Institute, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Science, Colorado State University, 300 W. Drake Road, Fort Collins, CO 80525, USA.
authors.forename: Mo D
authors.initials: MD
authors.lastname: Salman
mesh_terms: D000818:Animals; D004606:Elephants / Q000382:microbiology*; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000662:veterinary*; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*
keywords: Elephant; Internal amplification control; PCR; Trunk wash; Tuberculosis