Canis ISSN: 2398-2942

Actinomyces viscosus

Synonym(s): A. viscosus

Contributor(s): Richard Walker




  • Order: Actinomycetales.
  • Family: Actinomycetes.
  • Genus: Actinomyces.


  • Gk: actino- ray; myces- fungus.
  • L:viscum- bird-lime;viscosus- sticky.

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Clinical Effects



  • Oral mucous membranes and tooth surfaces.
  • May be found secondarily in the gastrointestinal tract.


  • Bacterial colonies form in tissue in microaerophilic conditions.


  • Most infections are endogenous.
  • May be transmitted by biting.

Pathological effects

  • Causes:
    • Discospondylitis as a result of migrating grass awns.
    • Localized cutaneous granulomas and abscesses Actinomycosis.
    • Thoracic granulomata and pyothorax Pyothorax.
  • A number of other Actinomyces spp can cause similar diseases.
  • Actinomyces horeovulneris is also commonly associated with migrating grass awns.
  • Actinomyces bowdenii is associated with mandibular abcesses and foreign body pyogranulomas.
  • Actinomycotic lesions in pigs, cats, hamsters and humans.


Control via chemotherapies

A. viscosus infections respond well to penicillin Benzylpenicillin and other antibiotics Therapeutics: antimicrobial drug , unlike Nocardia infections Nocardia spp which can produce a very similar clinical picture in dogs

Other countermeasures

  • Drainage of pus.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Kirpensteijn J & Fingland R B (1992) Cutaneous actinomycosis and nocardiosis in dogs: 48 cases (1980-1990). JAVMA 201 (6), 917-920 PubMed.
  • Edwards D F, Nyland T G, Weigel J P (1988) Thoracic, abdominal, and vertebral actinomycosis. Diagnosis and long-term therapy in three dogs. JVIM (4), 184-191 PubMed.
  • Hardie E M & Barsanti J A (1982) Treatment of canine actinomycosis. JAVMA 180 (5), 537-541 PubMed.