Equis ISSN 2398-2977

Blastomyces dermatitidis

Synonym(s): B. dermatitidis

Contributor(s): Susan Dawson, Graham Munroe, Richard Walker

Introduction

Classification

Taxonomy

  • Genus:Blastomyces.
  • Species:dermatitidis.

Etymology

  • Gk:blastos- sprout, germ;mukes- fungus.
  • Gk:derma- skin.

Active Forms

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Clinical Effects

Epidemiology

Habitat

  • There is limited evidence of natural reservoirs ofBlastomyces.
  • 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

  • Yeat 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. Protective immunity is cell-mediated.
  • Entry of conidia occurs, usually via the respiratory tract. Changes to yeast form in tissues.
  • Inflammatory response results in pyogranulomatous lesions in terminal bronchioles and lymph nodes.
  • Dissemination may occur to bones, bone marrow, eyes, skin, urogentital tract and mammary glands.
  • Animal usually presents with skin or respiratory signs, fever, anorexia, weight loss   Weight loss: severe  , ocular disease or locomotor disturbances. Rarely central nervous system signs.
  • Rare in horses.

Control

Control via chemotherapies

Vaccination

  • Not available.

Diagnosis

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Further Reading

Publications

Refereed papers


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