Coccidioides infection begins in the lungs, following inhalation of the spores. About 60% of infections resolve without ever causing symptoms and are only recognized by a positive coccidioidin skin test. In the remaining 40% of infections, symptoms range from mild (cold-like or flu-like) to severe (pneumonia). (See coccidioidomycosis.) In less than 1% of infections, widespread disease occurs when the fungus spreads from the lungs through the blood stream to involve the skin, bones, joints, lymph nodes, and central nervous system or other organs. Individuals of African or Philippine descent, and people with weakened immune systems due to AIDS, diabetes, or immunosuppressive medications, may develop more serious infections. Occasionally the acute infection may develop into a chronic pulmonary (lung) disease or can reactivate after a long latent period. A history of travel to an endemic region is the key to suspecting coccidioidal infection. Arizona, California (especially San Joaquin Valley), and -- to a lesser extent -- western Texas, are endemic regions in the USA. |