What causes Valley Fever?

Valley Fever is caused by species of the fungal genus Coccidioides (Onygenales, Ascomycota)

Coccidioides filamentous growth on solid media in vitro in the BSL3 lab (above left), arthroconidia by light microscopy (above right) and during an infection in human lungs (image form swjpcc.com)

How do people get sick from Valley Fever?

Coccidioides or Valley Fever infections result from inhaling fungal spores from desert soils. Once in human lung tissue, spores can travel throughout the body including to the central nervous system.

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Where is Valley Fever found?

In the United States, Valley Fever is found in desert regions including Arizona, California, Nevada, New Mexico, and Utah. Recently, reports were made of Valley Fever infections in Washington state. 


In  California the highest rates of infection are in Kern, Fresno, Kings, Monterey, San Luis Obispo, Santa Barbara, and Los Angeles counties

In Arizona the highest rates of infection are in Pima, Pinal, and Maricopa counties. 

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Is Valley Fever contagious?

No, Valley Fever cannot be spread person to person.

What are the symptoms of Valley Fever?

Elongated cold and flu like symptoms; fever, fatigue, muscle aches/joint pain, headache, cough. Some Valley Fever patients experience no symptoms, while others develop pneumonia or meningitis.  

Can you die of Valley Fever?

Yes. Many people clear Valley Fever infections over time while others become life threateningly sick. Our research is aimed at understanding what makes some Valley Fever isolates more virulent than others.

How many people are impacted by Valley Fever?

Rates  of infections are steadily increasing including infections in areas where Valley fever is endemic and reportable (Arizona, California, Nevada, New Mexico, and Utah).

Rates of Coccidioidomycoses from 1998-2016, graph from CDC.gov

How many people are affected by Valley Fever in California?

Cocci_CASept18 Cumulative Reported Suspect, Probable, and Confirmed Cases of Coccidioidomycosis in January through July by Cumulative Reported Suspect, Probable, and Confirmed Cases of Coccidioidomycosis in January through July by Local Health Jurisdiction and Year of Estimated Onset, California, 2016-2018


There were 3516, 6075, 8203 Valley Fever infections in 2015, 2016, and 2017 respectively. As of August 2018 there have been 4600. If these rates continue for the rest of the year we may have 9200 cases by years end. You can read more about these stats at the California Department of Public Healths website. 

Where can I learn more about Valley Fever?

You can use the links embedded here to access research papers, governmental, and news websites. You can also learn more about Valley Fever on the CDC website,  Mayo Clinic website, and at the Valley Fever Americas Foundation website. 

What kinds of Valley Fever research are happening at UCSF/UC Berkeley?

The questions our research group are interested in include:

How do genomes of Coccidioides isolates within a given population differ and how do these differences result in virulence?

Why do some Coccidioides strains from soil infect humans while others do not?

Why do some people clear Coccidioides infections while others die from infections of the same isolate?

How can we strategically identify drug targets for novel Valley Fever vaccines and therapeutics?

This project involves using whole fungal genome sequences to assess how much molecular diversity resides within populations of fungi that infect and can kill humans. A second goal is to identify genes in the genome that enable human fungal pathogens to colonize and kill their hosts. Together this information will help guide drug development efforts for Valley Fever. 

Population structure of Coccidioides posadasii isolates