Understanding Coccidioidomycosis

What is Cocci?

Coccidioidomycosis (cocci) is an infection of the lungs caused by inhaling spores of the fungus Coccidioides immitis. This fungus is present in the soil of the southwestern United States, California, and parts of Central and South America.

The disease is not spread from human to human. After one bout with cocci, the body develops immunity to a second infection.

How Serious is Cocci?

The infection is rarely fatal in healthy people. Some people with the disease develop pneumonia. In a very small number of cases, the infection spreads to other areas of the body, such as the meninges (membranes around the brain and spinal cord), bones, skin, and other tissues. These serious conditions may occur months after the initial infection.

Most people with the infection do not get sick at all; they don't even know they have the disease. Of those who do get sick, most have flu-like symptoms. Only a very small percentage of cocci patients develops the disease in its serious, disseminated form (widespread throughout the body).

What Causes Cocci?

Tiny cocci spores enter the body when they are inhaled. Most get caught in sticky mucus inside the airways and are moved back up into the throat where they are either spit out or swallowed harmlessly. But a few cocci work their way down the airways to the end of the passage: the little air sacs of the lung, where the air ends up when it is inhaled.

Deep in the lung, the spores begin to grow. They develop into pods that are filled with even tinier seeds. The pods burst open, the seeds pour out and spread in the lung and sometimes to other parts of the body. Wherever the spores settle down, the body reacts with inflammation. In the lungs, little patches of inflammation develop around the spores. Cavities or scars may result, and eventually deposits of calcium. 

When the spores stay in the lungs, the disease is said to be in its primary form. When the fungus spreads throughout the body -- to the internal organs, bones, brain, and even the skin -- cocci is in its disseminated form.