Canis ISSN: 2398-2942

Blastomyces dermatitidis

Contributor(s): Rosanna Marsella

Introduction

Classification

Taxonomy

  • Dimorphic fungus.

Active Forms

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Clinical Effects

Epidemiology

Habitat

  • 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.

Lifecycle

  • 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.

Transmission

  • 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

Control via chemotherapies

Vaccination

  • Not available.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • 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.
  • 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.
  • Arceneaux K A, Taboada J & Hosgood G (1998) Blastomycosis in dogs - 115 cases (1980-1995). JAVMA 213(5), 658-64.
  • Cote E, Barr S C & Allen C (1997) Possible transmission of Blastomycosis dermatitidis via culture specimen. JAVMA 210(4), 479-480.
  • 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.
  • 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), 1877-9.
  • Bloom J D, Hamor R E, Gerding P A (1996) Ocular blastomycosis in dogs - 73 cases, 108 eyes (1985-1993). JAVMA 209(7), 1271-4.
  • Rudmann D G et al (1992) Evaluation of risk factors for blastomycosis in dogs. JAVMA 201, 1754.
  • 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, 79.

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