New study urges earlier detection of Valley Fever as cases climb

A new study published in The Journal for Nurse Practitioners calls for a shift in how Valley fever is recognized and treated, warning that delayed diagnosis continues to prolong illness, drive unnecessary treatment and contribute to preventable deaths.

The paper was authored and led by Ayomidamope “Ayo” Adebiyi, DNP, a board-certified family nurse practitioner and clinical lead at UC Merced Occupational Health Services. Adebiyi recently completed her Doctor of Nursing Practice, with a focus on executive systems leadership and health policy, and a post-master’s certificate in nursing education, both at Johns Hopkins University.

The paper outlines a structured approach to help frontline providers identify the disease earlier—a step researchers say could significantly improve patient outcomes.

“Valley fever is an underdiagnosed but growing public health issue, especially in endemic regions,” the study noted, emphasizing that better awareness, earlier testing and consistent clinical practices are essential to reducing illness severity and health care costs.

Missed diagnoses, growing burden

Valley fever, or coccidioidomycosis, is caused by inhaling fungal spores that live in soil. While once considered a regional illness concentrated in the southwestern United States, it has now expanded beyond traditional boundaries and affected far more people than reported data suggest.

Researchers estimate that between 205,000 and 360,000 symptomatic cases occur annually—far higher than official counts. A major challenge is delayed recognition, with many patients waiting weeks for an accurate diagnosis while often receiving ineffective antibiotics.

Because symptoms such as fatigue, cough, fever and shortness of breath resemble more common respiratory illnesses, the infection is frequently overlooked in its early stages.

“Eighty percent of people with Valley fever don’t get the correct diagnosis until a median of 23 days after their first clinical contact, if they even get tested,” Adebiyi said. “That’s a lot of illness, a lot of days lost from work, and a lot of unnecessary antibiotics.”

Cases are rising

Overlapping environmental and demographic changes are driving the increase in Valley fever. Adebiyi pointed to climate patterns as a key factor, with longer droughts followed by rainfall disrupting soil and increasing the spread of airborne spores. At the same time, expanding development is increasing exposure.

“As rural areas are almost becoming semi-urban, there’s more construction, which disrupts the soil,” she said.

Improved reporting has made the disease more visible, though many cases still go undiagnosed when symptoms are mild or resolve on their own. The result is a disease that is both expanding geographically and still widely underrecognized—especially in areas where clinicians may not routinely consider it.

At the center of the study is the COCCI framework, a clinical guide designed to help nurse practitioners and other providers identify Valley fever sooner and manage it appropriately:

• Consider exposure: Assess whether patients live in or have traveled to endemic areas or have been exposed to dust, construction or soil disturbance
• Order diagnostic testing early: Especially for patients with persistent respiratory symptoms or those who do not respond to initial treatment
• Check for risk factors: Identify patients at higher risk for severe disease, including those who are immunocompromised, pregnant or have underlying conditions
• Check for complications: Evaluate for signs of more serious disease, such as neurologic symptoms or widespread infection
• Initiate appropriate care: Manage uncomplicated cases in primary care and refer severe or complex cases to specialists

At its core, the COCCI framework shifts clinical thinking from “treat first, test later” to “evaluate exposure, test early and manage deliberately.” Rather than relying on intuition, the framework provides a clear, step-by-step approach.

A defining feature of the COCCI framework is reassessment after initial care. Clinicians are encouraged to schedule follow-up visits, monitor symptoms and adjust treatment if patients do not improve.

Frontline providers play critical role

The study highlights the growing importance of nurse practitioners, who provide a large share of primary care, particularly in underserved and rural areas. Because they are often the first to evaluate patients with respiratory symptoms, their ability to recognize Valley fever is central to improving outcomes.

“The point of writing the paper was just to bring it into the national discourse,” Adebiyi said, noting that awareness must extend beyond traditionally affected regions.

Although many infections are mild or asymptomatic, others can lead to serious complications, including pneumonia or disease that spreads beyond the lungs.

Exposure risk is tied to the environment and activity. The fungus becomes airborne when soil is disturbed by wind, construction or farming.

People living or working near these conditions—including agricultural workers, construction crews and some incarcerated populations—face higher exposure risk. Certain groups are also more likely to experience severe illness, including pregnant women, people with diabetes or weakened immune systems, and people of Black and Filipino descent.

Because symptoms overlap with other diseases, testing is essential for diagnosis. Blood tests that detect antibodies are the most widely used method, though early infections may require repeat testing.

Many cases resolve without treatment, but more severe infections may require antifungal medications. Options remain limited; research is ongoing to develop better therapies and a potential vaccine.

UC Merced’s connection to Valley fever extends beyond Adebiyi’s clinical work. Faculty researchers at the university’s Biosafety Level 3 laboratory are studying Coccidioides, the fungus responsible for the disease, with the long-term goal of contributing to vaccine development.

As clinical lead of Occupational Health Services, Adebiyi plays a direct role in protecting those researchers, writing the safety protocols that govern work in the high-containment laboratory.

“I am not just writing about this disease academically,” she said. “I am actively working to keep the people studying it safe every day.”

For patients, recognizing when to seek further evaluation is critical.

“If two to three weeks go by and the antibiotics you’re taking don’t seem to be working, you should ask your primary care provider if you can get a test for Valley fever,” Adebiyi said.

Preventive steps—including avoiding dusty environments, limiting exposure during soil disruption and using masks when needed—can also reduce risk.

The study argues that consistent clinical vigilance, earlier testing and structured approaches such as the COCCI framework can significantly reduce diagnostic delays and improve patient care.

“Having this framework would really change outcomes,” she said. “If we can quickly identify Valley fever, we can change the quality of life for many people and even save some lives.”

Provided by
University of California

Who’s behind this story?

Lisa Lock

BA art history, MA material culture. Former museum editor, paramedic, and transplant coordinator. Editing for Science X since 2021.

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Alexander Pol

PhD nano-engineering from Delft University. Published researcher and journal reviewer. Brings scientific insight to content standards.

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