Coccidioidomycosis

Alternative names:

coccidiosis

Definition:

A disease caused by breathing in spores of a fungus (Coccidioides immitis) found in soil in desert regions of the southwestern U.S., Mexico, and Central and South America. It usually affects the lungs but can spread and affect many organs.

Causes, incidence, and risk factors:

Infection is caused by breathing in spores of the fungus, Coccidioides immitis, found in desert regions. About 60% of infections cause no symptoms and are only recognized by a positive coccidioidin skin test. In the remaining 40% symptoms range from mild to severe. Dark-skinned people and people with a compromised immune system tend to have more serious infections. Individuals with AIDS are at high risk not only for pulmonary coccidioidomycosis but for the disseminated form and cutaneous form of the disease.

The disease can have an acute, chronic, or disseminated form. Acute pulmonary coccidioidomycosis is almost always mild, with few or no symptoms, and resolves without treatment. The incubation period is 10 to 30 days. The incidence of acute coccidioidomycosis is 1 out of 100,000 people.

Chronic pulmonary coccidioidomycosis can develop 20 or more years after initial infection which may not have been recognized, diagnosed, or treated. Infections (lung abscesses) can form and rupture releasing pus (empyema) between the lungs and ribs (pleural space). The incidence of chronic disease is 1 out of 100,000 people.

In disseminated disease, extension of infection to the bones, lungs, liver, meninges, brain, skin, heart, and pericardium (sac around the heart) may take place. Meningitis occurs in 30 to 50% of cases of disseminated disease. The course of the disease may be rapid for immunosuppressed patients.