Valley fever is an infection caused by coccidioides, a fungus that generally prefers warm, arid climates and predominately lives in soil in the southwestern United States, according to the Centers for Disease Control and Prevention.

Studies show variable weather caused by climate change could spread the fungus to other parts of the country, said Dr. Paris Salazar-Hamm, a researcher at the University of New Mexico School of Medicine.

Fatigue Cough Fever Shortness of breath Headache Night sweats Muscle aches or joint pain Rash on the upper body or legs.

The fungal infection is endemic in the southwest, with most people experiencing mild to no symptoms, said Dr. Manish Butte, professor and division chief of immunology, allergy and rheumatology in the department of pediatrics at the University of California, Los Angeles.

It’s unclear why only a fraction of people exposed to the fungal spores develop severe disease but Butte's research suggests it may have something to do with an individual's immune system.

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