Canis ISSN: 2398-2942

Skin: canine leproid granuloma syndrome

Synonym(s): Canine leprosy; CLGS

Contributor(s): Prof Richard Malik, Susan E Shaw

Introduction

  • It is the most common mycobacterial disease of dogs in Australia.
  • Canine leproid granuloma syndrome (CLGS), or canine leprosy, was first described in a Boxer and a Bullmastiff from Zimbabwe in 1973. Reports of similar disease appeared in Australia soon afterwards.
  • Cause: fastidious mycobacterial species probably transmitted by biting insects.
  • Signs: single or multiple skin nodules commonly affecting head and ears.
  • Diagnosis: cytology or histological examination with special staining.
  • Treatment: observation; antimicrobials; surgical excision.
  • Prognosis: good in uncomplicated cases, self cure, surgical cure.

Pathogenesis

Predisposing factors

General

  • None reported.

Pathophysiology

  • Despite being first reported in 1973, etiopathogenesis of CLGS has not been elucidated.
  • Initial reports suggested that flies (or midges or mosquitoes) might be vectors of infection by inoculating mycobacteria from an environmental niche into susceptible tissues. The predilection for lesions to develop around the head (in regions favored by biting insects) supports this hypothesis.
  • A novel PCR product has been identified in samples from canine leproid granulomas. Analysis of the partial 16S rRNA sequence supports the notion that the novel species is a fastidious, slow-growing mycobacterium. This proposed novel mycobacterial sequence has been identified in material from more than 24 Australian cases of CLGS indicating that the species represented by this sequence is probably the principal causative agent of CLGS. Interestingly, the species represented by this sequence has never been recorded from mycobacterial granulomas affecting the skin or subcutis of cats, horses, people, or other non-canine mammalian species.
  • Leproid granulomas are confined to tbe subcutis and skin and do not involve regional lymph nodes, or internal organs. Consequently, affected dogs are not systemically ill.
  • The absence of systemic involvement suggests that the causal organism has low pathogenicity or special prerequisites, such as a specific temperature requirement, which permits them to survive and multiply in superficial tissues only.

Timecourse

  • Incubation unknown.
  • See prognosis.

Epidemiology

  • Unknown.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Dedola C, Zobba R, Pinna Parpaglia M L, Chessa B, Antuofermo E, Polinas M, Pittau M & Alberti A (2014) First report of canine leprosy in Europe: molecular and clinical traits. Vet Rec 174 (5), 120 PubMed.
  • Foley J E, Borjesson D, Gross T L et al (2002) Clinical, microscopic and molecular aspects of canine leproid granuloma in the United States. Vet Pathol 39 (2), 234-239 PubMed.
  • Malik R, Martin P, Wigney D I et al (2001) Treatment of canine leproid granuloma syndrome: preliminary findings in seven dogs. Aust Vet J 79 (1), 30-36 PubMed.
  • Hughes M S, James G, Ball N et al (2000) Identification by 16S rRNA gene analysis of a potential novel mycobacterial species as an aetiological agent of canine leproid granuloma syndrome. J Clin Microbiol 38 (3), 953-959 PubMed.
  • Charles J, Martin P, Wigney D I et al (1999) Cytology and histopathology of canine leproid granuloma syndrome. Aust Vet J 77 (12), 799-803 PubMed.
  • Malik R, Love D N, Wigney D I et al (1998) Mycobacterial nodular granulomas affecting the subcutis and skin of dogs (canine leproid granuloma syndrome). Aust Vet J 76 (6), 403-407 PubMed.

Other sources of information

  • Craig E Greene (2006) Infectious diseases of the Dog and Cat, Elsevier 3rd edition.
  • Mason K V, Wilkinson G T, Blacklock Z (1989) Some aspects of mycobacterial diseases of the dog and cat. In:Proceedings of the Annual Meeting of AAVD and ACVD, Davis, California p 36.
  • Ralph H (1979) Mycobacterial granuloma in dogs. In: Proceedings of the Post Graduate Foundation of Veterinary Science of the University of Sydney 37, 157-164.


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