UA Expertise on Valley Fever (Coccidioidomycosis)

UA Expertise on Valley Fever

Valley fever, also known as coccidioidomycosis or cocci, is primarily a lung disease that is common in the Southwest United States and northwestern Mexico.

Valley Fever

Caused by the fungus Coccidioides, Valley Fever grows in soils in areas with low rainfall, high summer temperatures and moderate winter temperatures. The fungal spores become airborne when the soil is disturbed by winds, construction, farming and other activities.

Valley fever is more likely to occur during certain seasons. In Arizona, the highest prevalence of infections occurs from June through July and from October through November. In California, the risk of infection is highest from June through November.​​​​

Map of Valley Fever impact

Chart of Valley Fever impact

Susceptible People

In susceptible people, such as those who are immunocompromised, and animals, infection occurs when a spore is inhaled. Within the lung, the spore changes into a larger, multicellular structure called a spherule. The spherule grows and bursts, releasing endospores, which, in turn, develop into spherules. Symptoms of Valley fever generally occur within three weeks of exposure. It is not a contagious disease – meaning it is not passed from person to person. Related infections are rare.

Many domestic and native animals are susceptible to the disease, including dogs, cats, horses, cattle, sheep, burros, coyotes, rodents, bats and snakes.

University of Arizona Valley Fever Center for Excellence

The Arizona Board of Regents established the UA Valley Fever Center for Excellence in 1996 for the benefit of the entire state. Based at the UA Health Sciences campus—which includes the UA College of Medicine – Tucson, College of Pharmacy, College of Nursing and Mel and Enid Zuckerman College of Public Health—the center has developed a research base that includes the state’s three universities, and an information program for the scientific community and the general public. Its work encompasses public awareness, clinical guidelines and training, and research into rapid detection methods for the disease as well as development of a vaccine for both animals and humans. Much of the center’s research is conducted at the UA BIO5 Institute.

Valley Fever Center for Excellence logo

The Valley Fever Center for Excellence was recently awarded a four-year, $4.8 million grant for research to speed development of a vaccine to combat Valley fever, the sometimes deadly respiratory illness caused by Coccidioides spores found in soils of the U.S. Southwest. The center will use the money to accelerate development of a Valley fever vaccine for dogs that one day may lead to a successful human vaccine. A California-based biotech company and Colorado State University have joined the center in the effort.


1) Pamphlet in English (PDF):

2) Pamphlet in Spanish (PDF):

3) Tutorial for Primary Care Professionals Booklet (PDF):


Valley Fever in People

Valley fever derives its name from its discovery in the San Joaquin Valley of California, where it was also referred to as "San Joaquin Valley Fever" or "Desert Rheumatism." The medical name for Valley fever is coccidioidomycosis (often shortened to "cocci" caused by the fungus Coccidioides spp. (C. immitis, C. posadasii).

It is not contagious. For most, symptoms — if any — are mild, including fatigue, fever, headaches, rash, night sweats, weight loss, joint or muscle aches. For some people, the disease may spread to the skin, joints, bone or, in the most severe cases, the brain.

The disease usually affects the lungs and can cause pneumonia.

It is found in the southern deserts of Arizona (including Maricopa, Pima and Pinal counties), the central valley and southern portions of California (including Fresno, Kern, and Kings counties), the southern tip of Nevada, southern Utah, southern New Mexico, western Texas (especially along the Rio Grande), and the northern and Pacific coastal areas of Mexico. Recently, a pocket of Coccidioides has been identified in Washington. Some areas have been identified in Central and South America as well.

For more information, visit

lungs with valley fever

skin with valley fever


Valley Fever in Dogs

Because of their susceptibility and popularity as human companions, dogs comprise the majority of animal cases of Valley fever. Owners spend hundreds to thousands of dollars each year, especially in Arizona, diagnosing, treating, and following up care for their dogs with Valley fever. It is estimated that Valley fever costs all Arizona dog owners at least $60 million per year.

For more information, visit 

dog xray with valley fever

dog paw with valley fever infection

UArizona Experts

Kenneth Knox, M.D. headshot image

Kenneth Knox, M.D.

Associate Dean, Faculty Affairs and Development, UA College of Medicine – Phoenix
Member, UAHS Asthma and Airway Diseases Research Center
Member, UA BIO5 Institute

Part of Dr. Knox’s research has been focused on various clinical and translational projects dealing with coccidioidomycosis including use of bronchoalveolar lavage to study lung mucosal responses to Coccidioides. A co-principal investigator for a clinical trial to test Valley fever rapid detection methods in Arizona through an NIH grant to Duke University Human Vaccine Institute, he has also been working on examination of radiographic manifestations of coccidioidomycosis and how antifungal prophylaxis affects lung transplant recipients.

Andrew Comrie headshot image

Andrew Comrie

Professor of Climatology, School of Geography and Development, UA College of Social and Behavioral Sciences

Comrie has been studying climatic impacts on the spread of coccidioidomycosis in the desert of Southern Arizona. His other interests include regional and local climate variability, air quality, climate-health relationships, mapping, spatial modeling and interpolation and the effects of climate change on human health.

Lisa Shubitz, D.V.M. headshot image

Lisa Shubitz, D.V.M.

Research Scientist, UA Valley Fever Center for Excellence

A veterinarian and leading expert on Valley fever in animals, Dr. Shubitz has focused her research on developing a vaccine for Valley fever, studying the epidemiology of the disease in canines, the ecological distribution of the fungus in Southern Arizona, and interactions between the host (both animal and human) and the fungus that causes Valley fever using animal models.

David Nix headshot image

David Nix

Professor, Department of Pharmacy Practice and Science, UA College of Pharmacy

Nix has played a key role in design and implementation of the Nikkomycin Z clinical trials at the UA Valley Fever Center for Excellence. He teaches infectious disease topics in multiple courses and precepts students and residents on related rotations. His other research interests include treatment of bacterial infections, antibacterial resistance and antimicrobial stewardship.

Media Contacts

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