Coccidioidomycosis

1
Coccidioidomycosis

• Epidemiology
• Highly endemic in the San Joaquin Valley of
  California
• Thrives in rodent burrows
• Aerosolized by tilling the soil

2
Coccidioidomycosis

• Epidemiology
• Disseminated cases occur most frequently in
  certain people
• Dark-skinned people more susceptible
• very young and very old
• pregnant women
• immunosuppressed

3
Coccidioidomycosis

• Clinical manifestations
• Frequently mild symptomatic or asymptomatic
  respiratory infections
• Typically resolves rapidly leaving the patient
  with a strong specific immunity to re-infection
• Can progress to a chronic pulmonary condition,
  then dissemination can occur which is often fatal
• Approximately 0.2 of symptomatic respiratory
  infections disseminate

4
Coccidioidomycosis

• Disseminated manifestations
• May involve cutaneous and subcutaneous tissues,
  meninges, bones, joints and visceral organs
• Most common cause of fungal meningitis in the
  United States
• Identification of C. immitis
• Unlike the other well known dimorphic fungi, C.
  immitis does not grow in the lab on BHI blood agar

5
Chronic cutaneous coccidioidomycosis showing
granulomatous lesions of the face
6
Extension of pulmonary coccidioidomycosis showing
a arge superficial, ulcerated plaque
7
Coccidioidomycosis

• Identification of C. immitis
• In vitro mould to yeast conversion (or more
  precisely mould to spherule conversion) is not
  routinely done in the clinical microbiology lab
• This conversion requires special media incubated
  in a moist CO2 enriched environment at 42oC

Debbie why is this necessary? Why not just take
samples from the patient?
8
Coccidioidomycosis

• Identification of C. immitis
• Mold to spherule conversion in vivo can be
  accomplished by injecting a saline suspension of
  a fresh culture into lab animals
• If the animal does not die within a week it must
  be sacrificed

9
Coccidioidomycosis

• Identification of C. immitis
• Touch preparations from lesions of the infected
  lab animals lung, liver or spleen will
  demonstrate spherules
• Spherules are round, hyaline, and large (30-60
  ?m)
• Mature spherules are filled with small ( 2-5 ? m)
  spores that result from the cleavage process
  (they do not bud as the tissue form of other
  dimorphics do)

10
Coccidioides immitis
Spherules in skin scraping from a cutaneous
lesion