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

N Z Vet J. 2009 Jun;57(3):122-31. 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. 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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adenoids / microbiology
  • Adenoids / pathology
  • Animals
  • Animals, Wild / microbiology*
  • Autopsy / veterinary
  • Diagnosis, Differential
  • Disease Vectors
  • Lymph Nodes / microbiology
  • Lymph Nodes / pathology
  • Mycobacterium bovis* / isolation & purification
  • Palatine Tonsil / microbiology
  • Palatine Tonsil / pathology
  • Polymerase Chain Reaction / veterinary
  • Tuberculosis / diagnosis
  • Tuberculosis / epidemiology
  • Tuberculosis / transmission
  • Tuberculosis / veterinary*