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

Authors: Gortazar C, Chambers MA, Gavier-Widen D, Cooke MM, Gallagher J
Publication: New Zealand Veterinary Journal, Volume 57, Issue 3, pp 122-131, Jun 2009
Publisher: Taylor and Francis

Animal type: Cattle, Deer, Livestock, Possum, Production animal, Ruminant, Sheep, Wildlife
Subject Terms: Bacterial, Diagnostic procedures, Epidemiology, International, Mycobacterial, Disease/defect, Pathology, Public health, Zoonosis, Infectious disease
Article class: Review Article

---

Abstract: 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. Acid-fast 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.
KEY WORDS: Bovine tuberculosis, Mycobacterium bovis, wildlife, Eurasian badger (Meles meles), brushtail possum (Trichosurus vulpecula), cervids, ferrets (Mustela furo), European wild boar (Sus scrofa)

---