Coccidioidomycosis (Valley Fever)

Valley Fever is an illness that usually affects the lungs.  It is caused by a fungus called Coccidioides. Coccidioides lives in the dirt. A hardy form of the fungus can live for a long time under harsh environmental conditions such as heat, cold, and drought, and is spread through spores in the air when the dirt is disturbed.  An estimated 150,000 Coccidioides infections occur each year in the United States, although more than half of these infections do not produce symptoms. Valley Fever fungus is found in some areas of the southwestern United States, and in parts of Mexico and Central and South America. These areas have dirt and weather conditions that allow the fungus to grow. In California, the fungus is found in many areas of the San Joaquin Valley (Central Valley). 

People can get Valley Fever if they breathe in the dust from the dirt that contains fungal spores. Fungal spores can get into the air when dirt containing the fungus is disturbed by digging, during construction, or under strong winds. Construction and farm workers, military personnel, archaeologists, and others who breathe in dust from the dirt in the areas where Valley Fever is common may be exposed to the fungal spores.  

Valley Fever is difficult to prevent. There is currently no vaccine; efforts to develop a vaccine are ongoing. Persons at risk for Valley Fever or for getting severe illness from Valley Fever should avoid exposure to dusty air in areas where Valley Fever is common.  Those exposed to dust during their jobs or outside activities in these areas should consider respiratory protection, such as a mask, during such activities.