ISSN 2398-2942      

Blastomyces dermatitidis


Rosanna Marsella




  • Dimorphic fungus.

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Clinical Effects



  • There is limited evidence of natural reservoirs of Blastomyces.
  • Soil saprophyte, but attempts to isolate the organism from soil have been inconsistent.
  • Colonizes animal wastes and decaying vegetation at low pH and in moist conditions.


  • Yeast form is found in tissues → reproduces by broad-based budding.
  • Yeast form occurs in soil and when grown at room temperature → reproduces asexually using conidia.
  • Also has a sexual stage, Ajellomyces dermatitidis.


  • Most commonly by inhalation.
  • Rarely percutaneous transmission from a bite.

Pathological effects

  • Impaired cell-mediated immunity predisposes to the infection and may be the result of the infection.
  • Both cell-mediated and humoral responses occur.
  • Entry of conidia occurs, usually via the respiratory tract.
  • Change to yeast form occurs in the tissues.
  • Inflammatory response occurs resulting in pyogranulomatous lesions in the terminal bronchioles and lymph nodes.
  • Dissemination may occur to:
    • Bones.
    • Bone marrow.
    • Eyes.
    • Skin.
    • Urogenital tract.
    • Mammary glands.
  • Animal usually presents with:
    • Skin or respiratory signs.
    • Fever.
    • Anorexia.
    • Weight loss.
    • Ocular disease.
    • Locomotor disturbances.
  • Rarely central nervous system signs.


Control via chemotherapies


  • Not available.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Baumgardner D J & Paretsky D P (1999) The in vitro isolation of Blastomyces dermatitidis from a woodpile in north central Wisconsin, USA. Med Mycol 37 (3), 163-168 PubMed.
  • Giles S, Klein B & Czuprynski C (1999) The effect of canine macrophages on the adherence and growth of Blastomyces dermatitidis yeast - evidence of a soluble factor that enhances the growth of B. dermatitidis yeast. Microbiol Pathog 27 (6), 395-405 PubMed.
  • Arceneaux K A, Taboada J & Hosgood G (1998) Blastomycosis in dogs: 115 cases (1980-1995). JAVMA 213 (5), 658-664 PubMed.
  • Côté E, Barr S C & Allen C (1997) Possible transmission of Blastomycosis dermatitidis via culture specimen. JAVMA 210 (4), 479-480 PubMed.
  • Bloom J D, Hamor R E, Gerding P A Jr. (1996) Ocular blastomycosis in dogs: 73 cases, 108 eyes (1985-1993). JAVMA 209 (7), 1271-1274 PubMed.
  • Kraweic D R, McKiernan B C, Twardock A R et al (1996) Use of an amphotericin B lipid complex for the treatment of blastomycosis in dogs. JAVMA 209 (12), 2073-5 PubMed.
  • Legendre A M, Rohrbach B W, Toal R L et al (1996) Treatment of blastomycosis with itraconazole in 112 dogs. J Vet Intern Med 10 (6), 365-71 PubMed.
  • Rudmann D G, Coolman B R, Perez C M et al (1992) Evaluation of risk factors for blastomycosis in dogs: 857 cases (1980-1990)​. JAVMA 201 (11), 1754-1759 PubMed.
  • Hawkins E C & DeNicola D B (1990) Cytologic analysis of tracheal wash specimens and bronchoalveolar lavage fluid in the diagnosis of mycotic infections in dogs. JAVMA 197 (1), 79-83 PubMed.

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