Lesson 3.3

• • have natural habit that is delimited to specific geographic regions
  • known as primary systemic fungal pathogens due to their ability to directly cause systemic infections
  • infections generally involve the deep viscera after dissemination of fungus from lungs

  Endemic Mycoses
• • all are caused by dimorphic fungi but isolation of yeast forms is diagnostic
  • acquired through inhalation of infectious conidia, this most frequently collected specimen is sputum
  • no person-to-person infection but requires BSL III (BSC class II)
  • exhibit mild flu-like symptoms
  • resolution confers immune protection

  Characteristics of Endemic/Primary systemic mycoses
• • A Ag - B. dermatitidis
  • 1,2&3 Ag - P. brasiliensis
  • H&M Ag - H. capsulatum (cross-reacts with B. dermatitidis)
  • HS, HL & F Ag - C. immitis


  Exoantigen tests for endemic/primary systemic mycoses
• • Blastomyces dermatitidis
  • Paracoccidioides brasiliensis
  • Histoplasma capsulatum ss. capsulatum & ss. duboisii
  • Coccidioides immitis & ss C. posadasii
  • Penicillium marneffei


  Etiologic agents of Endemic/primary systemic mycoses
• • Aspergillosis
  • Candidiasis
  • Cryptococcosis
  • Mucormycosis
  • Pneumocystis

  Opportunistic fungal infections
• • Blastomycosis
  • Coccidioidomycosis
  • Histoplasmosis
  • Paracoccidioidomycosis
  • Penicilliosis

  Endemic dimorphic
• • Endemic in North America
  • Causative agent of blastomycosis, Gilchrist disease, Chicago disease
  • resides in decaying wood


  Blastomyces dermatitidis
• cultured in medium with cycloheximide


  Culture of Blastomyces dermatitidis
• broad-based single-budding yeast with double contoured walls


  Tissue of Blastomyces dermatitidis
• conidiophores with lollipop appearance; pyriform conidia


  Mold of Blastomyces dermatitidis
• • endemic in South America


  Paracoccidioides brasiliensis
• • endemic in South America
  • Causative agent: blastomycosis, Lutz-Splendore-Almeida disease
  • pulmonary to systemic (cutaneous/GI mucosal/RES)
  • habitat not known, found in soil near armadillo burrows


  Paracoccidioides brasiliensis
• Multi-polar budding yeast ("mariner's" or "navigator's", or "pilot") wheel/ mickey mouse ears


  Tissue of Paracoccidioides brasiliensis
• • lollipop appearance with small-one celled conidia
  • septate hyphae with intercalated chlamydoconidium


  Mold of Paracoccidioides brasiliensis
• • Causative agent: darling's disease, cave/spelunker's disease
  • pulmonary to systemic (skin, soft tissues, bones, joints, meninges)


  Histoplasma capsulatum
• • endemic in north and south america
  • primary manifestations: pulmonary and disseminated infections


  H. capsulatum ss capsulatum
• • endemic in africa
  • primary manifestations: skin and bone lesions


  Histoplasma capsulatum ss duboisii
• • resides in soil, particularly heavily contaminated with bat/bird/starling guano
  • usually diagnosed through blood smears stained with Giemsa


  H. capsulatum
• thin-walled oval budding yeast cells within monocytes/macrophages

  Tissue of Histoplasma capsulatum
• tuberculate/echinulate macroconidia ("spike-like"); also produced by Sepodonium spp (blue rambutan)


  Mold of Histoplasma capsulatum
• • endemic in western america (California/Arizona region)


  Coccidioides immitis
• San Joaquin valley fever/ desert valley fever/ coccidiodal granuloma (pulmonary/allergic)


  Causative agent of Coccidioides immitis
• endemic near California region

  C. immitis
• endemic outside California region

  C. posadasii
• • resides in soil; one of the most important laboratory acquired infection (meninges)
  • NOT processed if not reference laboratory
  • *Filipino medtech dangerous

  Coccidioides immitis
• spherules containing endospores (endo-sporulating spherule)


  Tissue of Coccidioides immitis
• barrel-shaped hyaline arthroconidia


  Mold of Coccidioides immitis