The Fight Against Valley Fever

On New Year’s Day in 2012, Rob Purdie woke up with a crushing hangover, despite not drinking the night before. As the days went on, his debilitating headache didn’t relent. He went to a few urgent care clinics around Bakersfield, his hometown, receiving vague diagnoses and a few antibiotics courses. Nothing helped. He spent his hours lying on the couch in total darkness, even covering up the tiny lights on his cable box in attempts to stave off the headaches.

Six weeks into his misery, he started seeing double in the middle of a work presentation. His wife decided enough was enough and insisted he go to the hospital. On Valentine’s Day, lab results confirmed Purdie’s diagnosis: Valley fever, which had progressed to meningitis.

Valley fever, endemic to the southwestern U.S., Mexico and Central America, is a fungal infection that can have devastating complications, including pneumonia and meningitis. After a steady increase in reported cases since 2014, 2024 saw over 12,500 reported cases in California compared to the 7,400 reported in 2022. Those numbers are expected to keep climbing as climate change makes it easier for the spores to survive and cause infections in people.

Lurking in the dust

Valley fever is caused by spores from Coccidioides, or “cocci” fungus. Cocci grows underground, webbing out in a massive spindly network. When soil dries out and agricultural or construction work stirs up dust, cocci spores are released into the air. When those spores are inhaled, they can settle in the lungs and cause rash, cough and fever. More severe cases may develop into pneumonia. Many cases are mild, but around one percent of the time, the fungus disseminates and ends up in the bones, skin or brain. Those cases often require lifelong treatment and can be fatal.

The disease isn’t generally contagious between people — the only way to be infected is to inhale spores from the dirt. Thus, its spread is limited to areas where the fungus is endemic — Arizona, California’s Central Valley, Mexico and parts of Texas and South America. Because of its relatively small geographic range, the disease flies under the radar, even for those who live in at-risk areas.

This general lack of awareness means patients often don’t receive the appropriate diagnosis and treatment until they are experiencing severe symptoms. And those treatments aren’t designed with valley fever in mind, instead being adapted from regimens that were developed for other fungal infections. 

With cases already on the rise, climate change is expected to amplify the rate of infection of valley fever and other fungal diseases for a few reasons, Thompson says. For one, though many fungi can’t currently survive in the human body, because our core temperature is too hot to support fungal life, that could soon change. That’s because as the world warms, fungi are expected to adapt to higher temperatures, increasing their odds of survival in human hosts. 

Additionally, fluctuations in temperature and rainfall caused by climate change could allow more places to have the ideal cocci habitat that Arizona and Central California have now. The disease could eventually affect the entire western U.S. as far north as Canada, said John Galgiani, director of the Valley Fever Center for Excellence at the University of Arizona. 

Thompson hopes that new drugs in development will ease the growing burden of fungal disease for patients.

A passion for patients

Thompson’s interest in fungal disease started when he was infected with histoplasmosis as a college student in Missouri. Histoplasmosis is similar to cocci, Thompson said — it is caused by a fungus that grows underground, and inhaled spores can cause fever, cough and body aches. In severe cases, the fungus can spread to the brain and cause meningitis, like cocci.

Thompson, an 18-year-old college freshman at the time, was diagnosed after ignoring his swollen lymph nodes and fatigue for a few weeks. Upon receiving his diagnosis, “I thought, ‘Well, what is that?’” he recalled. “[I] started reading more about fungal diseases and was just sort of enamored and captured forever.”

Thompson studied histoplasmosis in medical school, then headed for San Antonio to train at a reference laboratory for fungal diseases. There, Thompson saw patients with valley fever and a host of other fungal diseases. “It was sort of like, ‘This is a huge problem,’’’ Thompson said. “It’s been about half of my research ever since.”

From there, he went to the UC Davis Cocci Diagnostic Lab. After he arrived, the lab began to branch out in its research interests. “We really ramped up our research publications,” Thompson said, “looking at clinically relevant problems in valley fever.”

At the UC Davis Center for Valley Fever, established in 2016, Thompson and his colleagues are working to understand how the disease affects patients’ metabolism, to untangle genetic risk factors, and to treat patients. As leading experts in the field, doctors and researchers at the center provide guidance to clinics throughout the region and treat patients with the most severe symptoms.

Thompson sees patients with valley fever and other infectious diseases at the UC Davis Medical Center. Through his telemedicine clinic, he also sees patients who are incarcerated in California state prisons, many of whom have cocci.

“We’re interested in all things valley fever,” Thompson said, “but particularly things that can help our patients get better.”

Treatment, or illness?

The standard treatment for valley fever consists of a regimen of drugs designed to fight other fungal infections. The drugs aren’t FDA-approved for treating cocci — running the clinical trials necessary to secure approval would be too expensive for a disease with relatively few patients. Instead, so-called “off-label” drugs are the best tools doctors have for treating valley fever.

Most valley fever patients will start on fluconazole, an antifungal approved for treating yeast infections. For a typical vaginal yeast infection, patients may take a one-time dose of 150 milligrams. Most patients tolerate treatment, pushing through common side effects such as nausea and abdominal pain. For cocci, however, patients take anywhere from 400 to 1,200 milligrams every day to target the stubborn fungus. The length of that intense regimen varies significantly, but patients are often on this plan for up to six months. At this higher dose, side effects can include nausea, dry skin and lips, and hair loss.

Eventually, many patients with severe disease “fail” fluconazole — either their cocci levels stop going down or they can no longer tolerate the side effects. Doctors will prescribe the next in the line of five oral antifungal drugs thrown at valley fever patients. All the drugs are in the triazole class of antifungals, and each one has its own drawbacks. One drug, voriconazole, increases sensitivity to light, resulting in frequent sunburns. Others can cause high blood pressure, put strain on the heart or interact poorly with other drugs, taking them off the table for certain patients and leaving them with few options.

Amphotericin B is the last resort for patients with severe disease that respond poorly to the oral triazole drugs. “Amphotericin B is nicknamed amphoterrible,” Thompson said. The treatment is infamous among medical professionals for causing severe symptoms, including nausea, dizziness, fever and chills.

Amphotericin B is given via intravenous infusion. Because Purdie had meningitis, doctors delivered the drug directly into a ventricle in his brain through a port in his skull twice a week. “It hits you all at once,” Purdie said. “You can feel the progression through your body as gravity brings it through.” Between receiving the injection, suffering through side effects, and anxiously awaiting the next round, Purdie’s treatment routine was all-consuming. “You give half your life,” to stop the disease from taking it, he said. He still receives injections periodically to manage his disease, despite the side effects.

Other repercussions from his valley fever treatment have continued to follow him. While he was on voriconazole, he repeatedly suffered severe sunburns. He has since had multiple bouts of skin cancer. He officially failed voriconazole and stopped taking it after his second skin cancer diagnosis.

“Even though they stopped what was causing it, the damage is done, and it keeps compounding,” Purdie said. “I’ve had skin cancer six times, maybe seven… I’m going to go in next week, and they’re going to cut off part of my ear.” He’s still careful to avoid sun exposure to minimize his risk — a difficult task in hot, sunny central California. He sold his golf clubs, wears a hat outdoors, and sees his dermatologist every three months.

For the few patients with aggressive infections that have settled outside the lungs, like Purdie, valley fever treatment is never over. Even when doctors can no longer detect cocci in a patient with meningitis, stopping treatment often gives the fungus a chance to pop up again, Thompson said. In many cases, patients must undergo arduous treatments for the rest of their lives.

A changing treatment landscape

“We do have patients with valley fever who just run out of options,” Thompson said. “They’ve gotten every drug available and nothing has worked.” When a patient gets to that point, their physician may turn to promising antifungal drugs that are still in development. One such drug changed everything for Torrence Irvin.

In 2018, then-44-year-old Irvin suffered severe cold symptoms for a few months. Eventually, his wife, Rhonda, insisted he seek treatment and drove him to a nearby hospital. There, doctors diagnosed him with pneumonia. His condition continued to worsen as he spent several months in and out of the hospital, staying there for weeks at a time. He suffered fevers and had trouble keeping food down due to nausea. He estimates that he lost 150 pounds over six or seven months.

Several months into his illness, a doctor from Irvin’s church suggested that he get tested for valley fever on the off chance he’d been infected with cocci in his northern California town. “Come to find out that that’s what I had,” Irvin said.

For around a year, Irvin made his way through the triazoles and amphotericin B. “I felt nothing,” he said. “I continued to vomit. I continued to get weak… laying in the doctor’s for months at a time.” He was losing muscle mass and couldn’t walk on his own, and continued to have difficulty breathing.

Eventually, his doctors referred him to Thompson and Bennet Penn at the UC Davis Medical Center. When Irvin still wasn’t getting better after more hospital stays, Thompson approached him with a new drug still in development: olorofim.

Thompson had read that the developing drug worked well in mouse models of valley fever and was trying it out for some patients. Irvin, his wife and his two daughters were desperate for a treatment that would make him feel better. “I could tell the toll that it was taking on my family,” Irvin said. “They have to see the fighter in me.” He agreed to start taking olorofim.

Slowly, he began to improve. He was able to walk a few steps at a time with a cane and he kept more food down than before. He felt like he was finally getting what his body had needed all along. “It gave me the feeling that I wanted to push forward,” he said, “that I had the strength to continue.” His illness was improving, and he felt no side effects from olorofim.

Today, he says he’s regained 80% of his health. The scar tissue that remains in his lungs from the disease limits his physical exertion, and he still isn’t working. But with more mobility and energy, he plays golf and works out when he can. Now, Thompson has taken him off olorofim to see how his body fares without it. Irvin is grateful that he’s had the chance to recover, and to play a part in learning more about valley fever treatment. “I’m glad I was able to go through it to educate someone else,” he said.

Olorofim, the first antifungal in the new orotomide class, has shown promise for valley fever and other fungal diseases. Thompson also has hopes for another drug, fosmanogepix, which is the first in the new gepix class of antifungal drugs. Like olorofim, fosmanogepix shows promise for fighting cocci in case studies. Both drugs are now in phase III clinical trials for fungal disease, and Thompson hopes they will be approved by the FDA in the next two years.

Right now, only two drug classes exist to treat valley fever: The triazoles, which include fluconazole and voriconazole, and the polyenes, such as amphotericin B. Olorofim and fosmanogepix would add two new drug classes to doctors’ arsenals, creating new treatment pathways for patients with stubborn disease or severe drug side effects. “Instead of giving another drug in that same class, which is likely to have similar toxicity, it’s nice to now have two totally different options,” Thompson said. Olorofim and fosmanogepix may also have fewer side effects overall and be more effective against cocci, he said.

“I’m very optimistic,” Thompson said. The drugs could even become the first line of defense, saving patients months or years of triazole treatments that can have harsh side effects and minimal efficacy against their disease, Thompson said.

As Thompson tries out new antifungals, he and other researchers at UC Davis seek to understand why valley fever affects some patients so profoundly while others barely show symptoms. It could have to do with genetic or environmental factors, Thompson said, which can be difficult to untangle. Eventually, though, that kind of genetic understanding could lead to individualized treatment plans for valley fever. “I’m hoping in the future we can do truly precision medicine, kind of like they do in cancer care now,” Thompson said.

That work could also allow early identification of high-risk patients. “We could do a blood test and say, ‘If you were to be infected with valley fever, you’re likely to get meningitis,’” Galgiani said.

In many ways, valley fever is still mysterious even to leading experts. There are researchers working on identifying at-risk patients, preventing infections through vaccine development and expanding treatment options. “There’s a lot of unanswered questions,” said Galgiani. “You could go in almost any direction you want and find something to study.” Together, these lines of research could completely change the valley fever landscape.

Advocacy, on the part of researchers and patients, is a key component in making sure valley fever research can continue. “We’re behind some other areas of fungal disease, certainly,” Thompson said, but he’s encouraged by a recent wave of interest and investment in the field.

A big round stone

After experiencing the most severe form of valley fever, and undergoing the most intense treatment options, Purdie became determined to make a change. “I’m going to do something about this,” he told his wife.

Purdie threw himself into advocacy work surrounding valley fever. He has helped create legislation to facilitate valley fever research and secured state funding to combat the disease. Some of that money funded the Valley fever Institute at Kern Medical, the hospital that diagnosed Purdie. He now serves as Patient and Program Development Coordinator there.

In 2022, Purdie helped found a nonprofit organization called MyCARE, short for Mycology Advocacy, Research and Education which advocates for education and research funding for fungal disease. He is also a patient advocate with the World Health Organization.

Purdie credits the success of his advocacy to the work and support of experts in the field. “I’m just a block of rock. I’m just a big round stone,” he said. “But if I have scientists and physicians and really smart people that can shape me, I become something that’s much sharper.”

 © 2025 Caroline Hemphill / UC Santa Cruz Science Communication Program