A review of infection of wildlife hosts with Mycobacterium bovis and the diagnostic difficulties of the 'no visible lesion' presentation

• Published in: New Zealand veterinary journal Vol. 57; no. 3; pp. 122 - 131
• Main Authors: Gavier-Widén, D, Cooke, MM, Gallagher, J, Chambers, MA, Gortázar, C
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis Group 01.06.2009
• Subjects: Adenoids - microbiology; Adenoids - pathology; Animal and Dairy Science; Animals; Animals, Wild - microbiology; Autopsy - veterinary; Bovine tuberculosis; brushtail possum (Trichosurus vulpecula); cervids; Diagnosis; Diagnosis, Differential; Disease Vectors; Eurasian badger (Meles meles); European wild boar (Sus scrofa); Feral animals; ferrets (Mustela furo); Husdjursvetenskap; Lymph Nodes - microbiology; Lymph Nodes - pathology; Mycobacterium bovis; Mycobacterium bovis - isolation & purification; Palatine Tonsil - microbiology; Palatine Tonsil - pathology; Polymerase Chain Reaction - veterinary; Tuberculosis; Tuberculosis - diagnosis; Tuberculosis - epidemiology; Tuberculosis - transmission; Tuberculosis - veterinary; Tuberculosis in animals; Veterinary Science; Veterinärmedicin; wildlife
• ISSN: 0048-0169; 1176-0710; 1176-0710
• DOI: 10.1080/00480169.2009.36891

The pathology, frequency and diagnostic implications of 'no visible lesion' (NVL) tuberculosis (Tb), i.e. infection with Mycobacterium bovis in the absence of macroscopic lesions, are described in a wide taxonomic range of wildlife hosts. Information collected and evaluated on the definition and occurrence of NVL Tb, histopathological characteristics, post-mortem techniques to detect minimal lesions, and diagnostic difficulties revealed most Tb-infected individuals with NVL had minute tuberculous lesions, which were difficult to see by eye. Acidfast organisms (AFO) were sometimes detected in the lesions. Ideally, mycobacterial culture of pools of lymph nodes and/or oropharyngeal tonsils is necessary for the accurate diagnosis of Tb in the absence of macroscopic lesions. At a very minimum, the diagnostic methods applied for studying the prevalence of Tb in the population should be clearly described, to allow comparison between studies.