PetriKey

Fungus

Paracoccidioides brasiliensis

Latin American dimorphic 'mariner's wheel' fungus

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High-yield clue

Multiply budding yeast forming a 'mariner's/pilot wheel' (ship's-wheel) in tissue from a Latin American patient is the core study clue.

Overview

A thermally dimorphic fungus endemic to Central and South America that causes paracoccidioidomycosis (South American blastomycosis), typically a chronic lung and mucocutaneous disease. Classic geographic dimorphic-fungus teaching organism of Latin America.

Classification

  • Thermally dimorphic fungus
  • Mold at 25C, yeast at 37C
  • Large yeast with circumferential multiple budding
  • Ascomycota
  • Endemic to Latin America

Lab & identification clues

  • 'Mariner's/pilot wheel' multiple-budding yeast microscopy vocabulary
  • Large round yeast (up to ~30-50 micron) with narrow-neck buds
  • Dimorphism shown by temperature shift
  • KOH/histology of mucosal or lung samples vocabulary

Associations

  • Endemic to Central and South America, especially Brazil
  • Chronic pulmonary disease and oral/mucocutaneous ulcers vocabulary
  • Rural agricultural soil exposure as risk vocabulary
  • Male-predominant chronic form teaching point

Commonly confused with

  • Blastomyces dermatitidis (broad-based single bud)
  • Coccidioides (spherule with endospores)

Your notes

Original student-study summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment, dosing, or specimen-handling guidance.

OpenStax: Microbiology 2e organism classification foundationssourceNCBI Bookshelf: Medical Microbiology organism chapterssourceCDC: CDC disease and public-health topic pagessource