Valley fever is acquired by breathing Coccidioides spores that are present in the air when soil and dust are disturbed. Valley fever cannot be spread from person to person. It is most often seen in people who live in or travel to California, Arizona, New Mexico, and Texas, where Coccidioides is naturally found. Coccidioides is also found in Mexico and Central America. People who have a higher chance of getting valley fever when exposed to Coccidioides are those with weakened immune systems due to either medical conditions or medications. For example, people who have diabetes, have human immunodeficiency virus (HIV) infection, take high doses of steroids, or are being treated with chemotherapy for cancer are at higher risk of valley fever. Pregnancy is also a risk factor.