Infection caused by the fungus Coccidioides immitis, largely confined to the southwestern United States and Central and South America, where it is sometimes called desert rheumatism or valley fever. At first the symptoms resemble those of the common cold or influenza; after apparent recovery the disease may recur in a more serious form, with fever, weight loss, and arthritic pains. The initial infection often dose not require treatment. Recurrent disease is treated by antifungal agents.