Coccidioidomycosis

Also called valley fever and San Joaquin Valley fever, coccidioidomycosis is a fungal infection. It occurs primarily as a respiratory infection, although generalized dissemination may occur. The primary pulmonary form usually is self-limiting and seldom fatal. The rare secondary (progressive, disseminated) form produces abscesses throughout the body and carries a mortality of up to 60%, even with treatment.

Such dissemination is more common in dark­skinned men and pregnant women. Immunosuppressive conditions, especially human immunodeficiency virus infection, Hodgkin's disease, and malignant lymphoma, also are risk factors for disseminated disease.

Coccidioidomycosis is endemic to the southwestern United States, especially between the San Joaquin Valley in California and southwestern Texas. It's also found in Mexico and central and South America.

Because of population distribution and an occupational link (it's common in migrant farm laborers), coccidioidomycosis strikes many Philippine Americans, Mexican Americans, Native Americans, and Blacks. In primary infection, the incubation period ranges from 1 to 4 weeks.

Causes

Coccidioidomycosis is caused by the fungus Coccidioides immitis. It may result from inhalation of C.immitis spores found in the soil in endemic areas or from inhalation of spores from dressings or plaster casts of infected people. It's most prevalent during warm, dry months.

Signs and symptoms

Most people with acute primary coccidioidomycosis have no symptoms. If symptoms develop, they appear 1 to 3 weeks after the person becomes infected. The symptoms are usually mild and include a cough, fever, chills, chest pain, and sometimes shortness of breath. The cough may produce sputum and even occasionally blood. Some people develop "desert rheumatism"-inflammation of the surface of the eye (conjunctivitis) and joints (arthritis) and the formation of skin nodules (erythema nodosum).

The progressive form of the disease is unusual and may develop weeks, months, or even years after the acute primary infection. Symptoms include mild fever and losses of appetite, weight, and strength. The lung infection may worsen, causing increased shortness of breath. The infection also may spread from the lungs to the bones, joints, liver, spleen, and kidneys. Infection of the brain and the tissues covering the brain (meninges) is often chronic.

Diagnostic tests

Sputum, urine, and pus should be examined for C. immitis by wet smear and culture. The mold form must be handled with care as it can infect laboratory personnel. Serologic tests are also helpful in the diagnosis.

Treatment

Mild primary coccidioidomycosis usually requires only rest and relief of symptoms. Severe primary disease and dissemination require I.V. amphotericin B. Patients with more indolent disseminated infection are given ketoconazole, itraconazole, or fluconazole.

CNS dissemination is usually treated with fluconazole but may require intrathecal administration of amphotericin B. Severe pulmonary lesions may require lobectomy in addition to chemotherapy if the infection is confined to one lung.

Alternative treatment

Alternative treatment for fungal infections focuses on creating an internal environment where the fungus cannot survive. This is accomplished by eating a diet low in dairy products, sugars, including honey and fruit juice, and foods like beer that contain yeast. This is complemented by a diet consisting, in large part, of uncooked and unprocessed foods. Supplements of vitamins C, E, A-plus, and B complex may also be useful.

Prevention

Because the fungus that causes coccidioidomycosis is airborne and microscopic, the only method of prevention is to avoid visiting areas where it is found in the soil. Unfortunately, for many people this is impractical. Maintaining general good health and avoiding HIV infection will limit coccidioidomycosis to the acute and relatively mild form in most people.