Coccidioidomycosis

Infectious Agent

The fungi Coccidioides immitis and C. posadasii .

Transmission

Through inhalation of fungal conidia from the environment. Not transmitted from person to person.

Epidemiology

Endemic in the southwestern United States and parts of Mexico and Central and South America. Travelers are at increased risk if they participate in activities that expose them to soil disruption and outdoor dust. Outbreaks have been associated with activities such as construction, archaeological excavation, and military training exercises.

Clinical Presentation

The incubation period is 7–21 days. Most infections (60%) are asymptomatic. Symptomatic infection ranges from primary pulmonary illness to severe disseminated disease. Primary pulmonary coccidioidomycosis is characterized by fatigue, cough, fever, shortness of breath, headache, night sweats, muscle aches, joint pain, and rash. These infections are often self-limited, and symptoms typically resolve in a few weeks to months. However, 5%–10% of people go on to develop serious or chronic lung disease, such as cavitary pneumonia, fibrosis, and bronchiectasis. In rare instances (approximately 1% of infections), dissemination to the central nervous system, joints, bones, or skin may occur.

Older people (≥65 years), people with diabetes, and people who smoke are at increased risk of developing severe pulmonary complications. People with depressed cellular immune function, pregnant women, and people of African American or Filipino descent are at increased risk of developing disseminated disease.

Diagnosis

The methods most commonly used to diagnose coccidioidomycosis are serology, culture, and histopathology. EIA is a sensitive serologic method to detect IgM and IgG. Immunodiffusion and complement fixation can also detect antibodies and are often used to confirm diagnosis. Isolation of Coccidioides from fungal culture of respiratory specimens or tissue provides a definitive diagnosis. Microscopy of sputum or tissue can identify Coccidioides spherules but has low sensitivity. Coccidioidomycosis is a nationally notifiable disease.

Treatment

Expert opinions differ on the proper management of patients with uncomplicated primary pulmonary disease in the absence of risk factors for severe or disseminated disease. Some experts recommend no therapy since most illnesses are self-limited, whereas others advise treatment to reduce the intensity or duration of symptoms. Treatment with antifungal agents has not been proven to prevent dissemination. People at high risk for dissemination and people with the following clinical manifestations should receive antifungal therapy:

  • Severe acute pulmonary disease
  • Chronic pulmonary disease
  • Disseminated disease

Depending on the clinical situation, azole antifungal agents or amphotericin B may be used.

Prevention

Limit exposure to outdoor dust in endemic areas.

CDC website: www.cdc.gov/fungal/diseases/coccidioidomycosis

Bibliography

  1. Ampel NM. Coccidioidomycosis. In: Kauffman CA, Pappas PG, Sobel JD, Dismukes WE, editors. Essentials of Clinical Mycology. New York: Springer Science+Business Media, LLC; 2011. pp. 349–66.
  2. Ampel NM. Coccidioidomycosis: a review of recent advances. Clin Chest Med. 2009 Jun;30(2):241–51.  [PMID:19375631]
  3. CDC. Coccidioidomycosis in travelers returning from Mexico–Pennsylvania, 2000. MMWR. 2000;49(44):1004–6.  [PMID:11097140]
  4. Chiller TM, Galgiani JN, Stevens DA. Coccidioidomycosis. Infect Dis Clin North Am. 2003 Mar;17(1):41–57, viii.  [PMID:12751260]
  5. Crum NF, Lederman ER, Stafford CM, Parrish JS, Wallace MR. Coccidioidomycosis: a descriptive survey of a reemerging disease. Clinical characteristics and current controversies. Medicine (Baltimore). 2004 May;83(3):149–75.
  6. Galgiani JN, Ampel NM, Blair JE, Catanzaro A, Johnson RH, Stevens DA, et al. Coccidioidomycosis. Clin Infect Dis. 2005 Nov 1;41(9):1217–23.  [PMID:16206093]
  7. Rosenstein NE, Emery KW, Werner SB, Kao A, Johnson R, Rogers D, et al. Risk factors for severe pulmonary and disseminated coccidioidomycosis: Kern County, California, 1995–1996. Clin Infect Dis. 2001 Mar 1;32(5):708–15.  [PMID:11229838]
  8. Thompson GR, 3rd. Pulmonary coccidioidomycosis. Semin Respir Crit Care Med. 2011 Dec;32(6):754–63.  [PMID:22167403]

Authors

Tom M. Chiller, Paige A. Armstrong, Orion Z. McCotter