COALINGA, Calif.  When any of the 5,300 inmates at Pleasant Valley State Prison begin coughing and running a fever, doctors do not think flu, bronchitis or even the common cold.

They think valley fever; and, more often than they would like, they are right.

In the past three years, more than 900 inmates at the prison have contracted the fever, a fungal infection that has been both widespread and lethal.

At least a dozen inmates here in Central California have died from the disease, which is on the rise in other Western states, including Arizona, where the health department declared an epidemic after more than 5,500 cases were reported in 2006, including 33 deaths.

Endemic to parts of the Southwest, valley fever has been reported in recent years in a widening belt from South Texas to Northern California. The disease has infected archaeologists digging at the Dinosaur National Monument in Utah and dogs that have inhaled the spores while sniffing for illegal drugs along the Mexican border.