PHOENIX—After Daniel Sestiaga was infected with COVID-19 in 2020, the 32-year-old Tucson resident and member of the Fort Yuma Quechan Tribe was relieved that his symptoms were “nothing too crazy.”

But in July 2020, more than a month into his recovery, he still couldn’t seem to catch his breath. It got worse, and he soon found himself in the hospital. A second positive test for coronavirus placed Sestiaga in the COVID ward of Banner – University Medical Center in Tucson, now with a tube protruding from his back to drain the fluids that had surrounded his lungs. 

As his optimism about the initial symptoms waned, he wondered if something else could be causing his sickness. He started to worry. “The last thing I ever wanted to do was end up in a COVID unit,” Sestiaga said. “People never make it out of there, you know?”

Blood tests confirmed what he could feel but didn’t know why: It wasn’t the coronavirus that was still ravaging his lungs. “An infectious disease doctor comes in and says, ‘You have Valley fever,’ Sestiaga recalled. “I said, ‘What is Valley fever?’”

The diagnosis, the result of a disease caused by a fungus endemic to the Southwest, is a respiratory infection with symptoms that can range from fatigue and cough to pneumonia. In rare cases, Valley fever can spread throughout the body, sometimes infecting the brain and spinal column, causing debilitating illness that can lead to lifelong medical care. It’s also deadly. 

Valley fever killed 39 people across Arizona in 2019, and a recent review of death certificates and hospital discharge data indicates fatalities could be two to seven times higher. From 2011 to 2017, research shows Arizona led the country in Valley fever infections with about two-thirds of the nearly 100,000 known diagnoses across the nation. Experts believe this too is a likely undercount—the number of symptomatic cases nationwide could be anywhere from six to 14 times higher than what’s been reported.

Evidence points to Valley fever as a growing problem in Arizona, yet little is known about who is most impacted by a pathogen that now sickens more people each year in Arizona than in any other state. Research shows the most serious form of the illness disproportionately impacts people of color, and likely those who work outdoors, but insufficient data collection, Arizona policies that limit workers’ compensation claims and a dearth of state and federal funding further shield the public from fully understanding the dangers the disease poses.


Arizona health officials said a 2020 rise in the number of cases could be attributed to increased testing and hospitalizations from COVID-19, or changes in weather patterns, but data shows the state’s number of Valley fever infections for 2021 is so far outpacing the previous year by 23%—with more than 8,200 confirmed cases so far this year.

“Even though (Valley fever) is one of the most reported diseases here, it is not really super well investigated,” said Dr. Mariana Singletary, epidemiologist and infectious disease surveillance manager for Pinal County Public Health. She said diseases such as those that can transfer from one human to another or that have more straightforward prevention methods often take priority. 

The lack of rigorous Valley fever investigations at the county level, Singletary added, is partially because of limited funding and staffing, and “we also don’t have the mandate to do it.”

Funding for Valley fever surveillance has appeared just once in the past 14 years as a $300,000 line item in the state health department budget, approved by the Arizona Legislature in 2007. The direct lifetime cost of medical care per person for a Valley fever infection, for example, ranges from $23,192 in uncomplicated cases to $1.26 million in the most serious, according to an analysis of diagnoses made in 2019. 

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For Sestiaga, it took a two week stay in the hospital and four liters of fluid to be drained from his lungs before he was discharged in September 2020. But three months later the coughing returned, and when he saw the sputum was tinged with blood, he started to panic.

He was worried he might be dying. What Sestiaga did not know at the time, and what his doctors would later find out, is that the fungus had left his lungs and was spreading to other parts of his body.

Dangerous dust

Valley fever is the colloquial term for coccidioidomycosis, a disease caused by fungus in the genus Coccidioides that naturally occurs in soil. Spores of Coccidioides are extremely small, slightly smaller than a single red blood cell, and are easily picked up by wind and movement. The spores infect the lungs when inhaled by people or animals, but it is not passed from person to person.

It has been nearly a century since medical researchers at Stanford University realized the fungus Coccidioides immitis was causing an illness characterized by cough, fever and pneumonia. The “valley” in Valley fever refers to the San Joaquin Valley in California where the disease was first linked to the fungus. 

Researchers initially thought the pathogen was limited to California’s Central Valley until World War II, when coccidioidomycosis outbreaks erupted among populations of servicemembers at what is now the Florence Military Reservation and now-closed Williams Air Force Base in Arizona. In the early 1940s, people of Japanese descent suffered from the disease when they were forcibly interned at a camp on the Gila River Indian Reservation outside of Phoenix.

While Valley fever was first identified in California, it has since become a more pervasive problem in Arizona. In 2019, the last year of comprehensive statistics available from the Arizona Department of Health Services, there were 144.1 cases per 100,000 residents in the state. In California, for the same year, the case rate was just 22.5 cases per 100,000 residents.

A purple stained thin section of mouse lung showing parasitic fungus
A purple-stained thin section of a mouse lung shows Coccidioides spherules five day post-infection. A spherule is the parasitic form of the fungus that grows inside the human or animal host. Photo courtesy Bridget Barker | NAU

Dr. John Galgiani, the director of the Valley Fever Center for Excellence at the University of Arizona, has long recognized the importance of researching the pathogen. Researchers at the Center study Valley fever and help educate medical professionals about the disease. But he said it’s been difficult at times to generate enough funding or interest in its dangers. “But the data don’t lie, I didn’t make these numbers up,” he said.

Most cases, around 60%, are mild or asymptomatic. The remaining cases present with flu-like symptoms including fatigue, fever and cough. Among those, however, an estimated 5 to 10% of people develop more serious complications that include long-term lung problems. And 1 to 5% of people develop disseminated Valley fever, or when the disease spreads outside of the lungs to other parts of the body, which can cause lengthy debilitating illness or death. 

By the time Sestiaga started coughing up blood in early 2021, he had already completed a three month regimen of the antifungal drug fluconazole, one of the few prescriptions used to treat the disease. 

Daniel Sestiaga holds a medication planner filled with Fluconazole pills on his kitchen table in Tucson, Arizona, on Sept. 17, 2021. Fluconazole is one of a few antifungal treatments available to combat valley fever. Photo by Alberto Mariani for AZCIR
Daniel Sestiaga shows his fluconazole medication container at his Tucson home. Photo by Alberto Mariani for AZCIR
Bottles of the antifungal medication Fluconazole sit on the kitchen table at Daniel Sestiaga’s home in Tucson, Arizona, on Sept. 17, 2021. Photo by Alberto Mariani for AZCIR
Fluconazole is one of just a few medications used to treat Valley fever. Photo by Alberto Mariani for AZCIR

So when scans revealed there were nodules in Sestiaga’s lungs, his pulmonologist scheduled a biopsy to make sure they weren’t cancerous. It wasn’t until a new symptom emerged that Sestiaga and his doctors knew his initial disease was still present. Soon after the lung biopsy, masses appeared on his back and chest. A second biopsy in May 2021 revealed that the lumps were full of fluid containing Coccidioides, meaning the fungal spores that first entered Sestiaga’s lungs had now spread throughout his body. 

For now, Sestiaga is back on what he called a “hefty dose” of fluconazole, and with it a sense of hope that at least he and his doctors know what’s causing his ailments. 

A “disease of color”

Anyone in rural or urban areas of Arizona can be infected by Valley fever, though epidemiological investigations of patient charts show certain racial and ethnic groups are at a higher risk for the more serious disseminated disease.

But tracking correlations between race or ethnicity and this disease is difficult in Arizona because of how the state collects the data. In 1997, after a steady increase in cases in the 1990s, laboratories were required to report diagnoses of Valley fever to ADHS. Because the information is automatically reported by labs, the state does not require them to transmit all patient data to the health department. 

According to a Centers for Disease Control and Prevention report on Valley fever from 2019, Arizona leads the way in missing race and ethnicity data, with just 22% of cases with complete race data and 18.6% with complete ethnicity data.

The same CDC report said that collecting data, such as detailed patient characteristics and disease severity, may help researchers and officials create targeted educational efforts in Arizona and California in particular. 

Galgiani said research shows that disseminated Valley fever is what he calls a “disease of color” in Arizona. While he said race is a “very poor genetic marker” biologically speaking, “anyone that’s really been involved with this disease is pretty convinced that African Americans are disproportionately affected.” 

Galgiani and colleagues are now researching the relationship between the immune system and genetics of patients with severe Valley fever. Their studies show there may be specific genetic markers that make the disease worse for certain people. 

Dr. Jonathan Iralu, an infectious disease specialist for Indian Health Services in Gallup, New Mexico, has seen what he called a  “steady stream of Valley fever” over the past two decades among Native American patients who have mostly acquired the disease in the Sonoran Desert.

Iralu said when they return home, patients have chronic diseases related to Valley fever, such as such chronic pneumonia, meningitis or bone infections.

A study released in June 2021, although not yet peer reviewed, shows Native Americans may also be disproportionately impacted by Valley fever in northern Arizona. The study reviewed patients hospitalized for the disease at Northern Arizona Healthcare in Flagstaff over an 18-month period and found that out of 38 patients, 22 were classified as American Indian/Alaskan Native. While this represents 57.8% of cases, American Indian/Alaskan Natives make up just 25.9% of the Coconino County population. 

Dr. Joel Terriquez, an infectious disease physician at Northern Arizona Healthcare in Flagstaff and author on the study, said he sees a number of Native American patients who have likely acquired the disease on the Navajo Nation. “I know it’s not necessarily just localized to the desert,” he said. “No one really talks about Native Americans, I believe that the information is very limited.” 

Sestiaga, whose disease spread into disseminated Valley fever, is a member of the Fort Yuma Quechan Tribe. He said that even though he has a master’s degree in public health from the University of Arizona, he had never heard of Valley fever until he was diagnosed. 

He thinks there is likely “a high prevalence of folks that have probably either been diagnosed or even misdiagnosed” among indigenous communities because there is a lack of information sharing with tribes and overall limited access to care. 

On-the-job Valley fever infections hard to track in Arizona

It is difficult to discern exactly where someone contracts Valley fever, Galgiani said, because the spores are so small even light breezes are enough to move them around. 

The CDC suggests some people are at higher risk of contracting Valley fever based on their occupations, such as geologists and construction or agricultural workers, for example, because they are more likely to stir up dirt where Coccidioides may live. 

A review of all known outbreaks of Valley fever from 1940 until 2015 shows only four have been reported in Arizona, and three were from the 1940s. This may be because Valley fever occurs in dense population centers, so it is hard to identify an outbreak cluster, or because it is not a condition that is reported to Arizona’s occupational health department, meaning outbreaks could go undetected.

Made with Flourish

In the 1970s, two cases brought before the Arizona Court of Appeals led to the court’s decision that it is too difficult to prove an employee caught the disease while at work, so the claims would not be accepted. 

In California, a workers’ compensation appeal board came to the opposite conclusion in 1968, and allowed Valley fever as a compensable claim even though the causal relationship between a job and the illness is difficult to prove.

Walter Jones, the director of occupational safety and health for the Laborers’ Health and Safety Fund of North America, a Washington, D.C.-based group that works with union workers and employers, has heard about Valley fever complaints from workers in California, but not in Arizona. “There’s certainly an occupational issue (in Arizona),” Jones said.

“Because California has this system set up with occupational related outbreaks, they just have a much better system to detect (Valley fever) outbreaks than we do,” said Dr. Rebecca Sunenshine, the medical director for disease control at the Maricopa County Department of Public Health. 

Not knowing how the disease impacts workers in Arizona is a gap in knowledge, she said, so researchers are now analyzing survey results from workers in Maricopa County that have been diagnosed with Valley fever. The research, being done in collaboration with the Occupational Safety and Health Administration, seeks to better understand the risks Arizona workers face.  

Unlike Arizona, California has fined construction companies for failing to control employees’ exposure to Valley fever. Gov. Gavin Newsom passed a law in 2019 that requires construction employers to educate their employees about the disease, including the importance of reporting possible infections to improve surveillance and outcomes from early treatment. 

Dearth of state, federal funding have limited Valley fever research in Arizona

It’s been 15 years since Valley fever last caught significant attention from an Arizona governor. Gov. Janet Napolitano signed an executive order to fund Valley fever in 2006 after a large spike in cases that year. The order dedicated $50,000 to ADHS for “use in combating the outbreak of Valley fever in Arizona.” 

A one-time, $300,000 special line item in the state budget followed in 2007, directed to ADHS for “Valley Fever Surveillance.” Galgiani said this funding led to an academic publication on coccidioidomycosis surveillance that was an “extraordinary milestone” because it revealed people who were knowledgeable about Valley fever before they got sick were tested and diagnosed faster than those who did not know of the disease. 

From 2010 until 2012, the Arizona health department received $100,000 per year from what was then known as the Arizona Biomedical Research Commission, a government agency designed to fund health research. The commission, disbanded in 2017, is now part of ADHS and is known as the Arizona Biomedical Research Centre.

There is one Valley fever specialist in the state health department that is funded by the CDC, according to Jessica Rigler, an assistant director at ADHS. Since 2012, the primary funding source for Valley fever work at the state level has come from a CDC Epidemiology and Laboratory Capacity grant. This grant has ranged from around $31,000 in 2013 to $135,000 in 2020. 

At the federal level, however, Rep. Kevin McCarthy, R-Calif., introduced the FORWARD Act in 2018 and 2019. The Act, which stands for “Finding Orphan-disease Remedies With Antifungal Research and Development Act,” was focused on funding disease research, including antifungal treatments and a potential Valley fever vaccine now under development. Sens. Martha McSally, R-Ariz., and Kyrsten Sinema, D-Ariz., also introduced the FORWARD Act to the Senate in 2019

“The good news is that support for more research dollars is bipartisan,” said Rep. Greg Stanton, D-Ariz., an original co-sponsor of the act in 2019. The Valley fever bills didn’t make their way through Congress that year, but Stanton said they plan to re-introduce it again. 

In July 2021, Rep. David Schweikert, R-Ariz., another original co-sponsor of the FORWARD Act, introduced an amendment to a 2022 House appropriations bill that includes $2 million for the CDC’s Emerging Zoonotic and Infectious Disease account for coccidioidomycosis and other fungal diseases. 

“At a national level, it’s important that we provide more dollars for research, for basic research into the cause of Valley fever and vaccine possibilities,” Stanton said. “But certainly more can and should be done at the state level as well since Arizona is hit harder by Valley fever probably more than any other state in the country.”

Daniel Sestiaga is shown outside his home in Tucson, Arizona, on Sept. 17, 2021. After he was first diagnosed with Valley fever in 2020, Sestiaga’s infection would later spread throughout his body, turning into the most severe form of the disease known as disseminated Valley fever. Photo by Alberto Mariani for AZCIR
Daniel Sestiaga is shown outside his home in Tucson, Arizona, on Sept. 17, 2021. Photo by Alberto Mariani for AZCIR

Sestiaga, still recovering from his illness, decided to go public with his struggle and post about his ordeal on social media. He said it was “shocking” to see the amount of responses he received. People were replying with their own personal tales of the disease and wanted to speak with him more about it.

Sestiaga thinks more education would be helpful, either from counties or government officials. He works at Tohono O’odham Community College and said he now wants to use his position in academia to educate colleagues and students about Valley fever to create awareness in his community.

“Just being able to share this anecdotal information and like, the story itself? That’s powerful.”

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Shaena Montanari is an investigative reporter for AZCIR focused on covering health disparities. Her position is partially funded by Report for America, a national program that supports local journalists.