Bovis ISSN 2398-2993

Skin tuberculosis

Synonym(s): atypical mycobacteriosis, tuberculosis

Contributor(s): Catherine Fraser , Ben Dustan

Introduction

  • Cause: atypical mycobacteria, occasionally M. bovis.
  • Signs: papules and nodules on the distal limbs.
  • Diagnosis: acid fast bacteria seen in stained smear preparations of pus and in dermal macrophages.
  • Treatment: usually not undertaken.
  • Prognosis: tend not to heal but little effect on animal.

Pathogenesis

Etiology

  • Likely skin contamination of wounds is the entry site for acid fast organisms.
  • Atypical mycobacteria are ubiquitous environmental saprophytes.

Predisposing factors

General

  • Poor housing.
  • Rough pasture.

Pathophysiology

  • Acid-fast bacteria stimulate the body's production of nodules as a walling-off mechanism.
  • Nodules result from massive infiltration of inflammatory cells into the dermis and subcutis often neutrophilic in character possibly with histiocytes and giant cells and contain thick creamy to grey pus.
  • Lymph vessels may be thickened.

Epidemiology

  • M. fortuitum.
  • M. kansasii.
  • M. bovis Mycobacterium bovis.
  • Majority of cases defy attempts to isolate and identify causal organism although they are gram positive and acid-fast.
  • Modern bacterial culture techniques usually identify the casual organism although in practice this is not often done, they are gram positive and acid-fast.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed Papers

Other sources of information

  • Andrews A H  (1997) Lecture notes from Royal Veterinary College for Skin Diseases of Farm Animals.
  • Blowey R W & Weaver A D (1991) Colour atlas of diseases and disorders of cattle. Wolfe.
  • Scott D W (1988) Large Animal Dermatology. W B Saunders.

Organisation(s)


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