Subscribe to Newsletter
Subspecialties Microbiology and immunology, Clinical care

Don’t Kick the Dust: Disease in Climate Change California

An interview with Royce H. Johnson

California is hot – and it’s getting hotter.

The Golden State is used to periods of intense heat and drought, but man-made climate change is making central California hotter and drier for longer than before. Predictions on the lower end suggest that the state’s annual average temperature will rise by 3–4°C by 2100 (1). This is bad news for the environment, agriculture, and general human survival. But there are some who will benefit from this change: two humble fungi named Coccidioides immitis and Coccidioides posadasii. They are present across the southern United States (though most prevalent in California) and thrive in hot, dry conditions. Unfortunately for us, the pair are also responsible for coccidioidomycosis, a fungal disease also known as cocci, desert rheumatism, and valley fever. Soil disruption – from construction to earthquakes – ejects infectious fungal spores into the air, where they can be inhaled to cause disease. Symptoms of valley fever are often mild – but not always.

In September 2022, the National Institutes of Health (NIH) reported on how valley fever cases have shot up in recent years (2). The numbers are still small, but this relative rise is predicted to increase further. And though the disease has, until now, lain in relative obscurity, one organization – the Valley Fever Institute – has been working since the 1950s to better understand and combat it. Now, with climate change taking center stage, the VFI is in greater demand than ever.

We spoke with Royce Johnson, Chief of Infectious Disease at Kern Medical and Medical Director at the VFI, to learn more about this insidious disease.

Could you please introduce us to your work?

My major research activity has been in coccidioidomycosis. One might ask, “Why would someone who had an NIH virology training grant in his fellowship at UC Irvine turn his attention to a fungus?” Two reasons: one, that’s what we have, and two, the mentorship of Hans E. Einstein, among others. I joined Kern Medical in 1976 and have chaired the Department of Medicine, led the Division of Infectious Disease, and chaired or participated in almost every committee in the hospital during my tenure. With the establishment of the VFI, my duties have shifted to focus more strongly on directing our research and education efforts.

How long have you been involved with the Valley Fever Institute?

For more than seven decades, Kern Medical has cared for those suffering from valley fever. Our long history with valley fever care began in the 1950s with Hans E. Einstein, who led efforts that included treatment, research, education, and awareness. In 2015, Kern Medical formalized those efforts by institutionalizing the VFI. In the summer of 2020, the VFI opened its new state-of-the-art research and treatment facility.

For those unfamiliar with the California climate, how is it changing?

California’s climate has always been varied due to the state’s large geographic area. Central California has always experienced hot summers and periods of drought – but, recently, the periods of drought have been increasing in frequency and duration and the number of triple-digit days during the summers seems to be increasing as well. Additionally, the population in the Central Valley is growing due to the area’s affordability relative to California’s coastal and metropolitan areas.

Are there other endemic diseases in California that might worsen with the changing climate?

I can’t predict the future, but I have concerns that climate change and the arrival of Aedes aegypti (a type of mosquito known to be a disease vector) could bring dengue, chikungunya, Zika and yellow fever to the region.

Is treatment for valley fever accessible (and affordable)?

Treatment is accessible, generally speaking. Because we are the safety net hospital for our community, our staff is experienced in helping patients access the available assistance programs. We also do our best to ensure that all patients receive care and treatment, regardless of their ability to pay. As the endemic areas expand, this could become a problem for some communities in states that do not offer access to healthcare and safety net healthcare.

If the fungus is present in soil, are there health implications for people working in agriculture and farming?

Not specifically those occupations, because the two Coccidioides species do not survive in irrigated and fertilized soil. However, people in outdoor occupations overall do have some level of increased risk due to the amount of time they spend exposed to ambient air, dust storms, and wind events. Workers involved in large-scale commercial green energy jobs may have an elevated risk because these projects frequently occur in areas that were previously undisturbed and may contain pockets of valley fever.

Does the VFI have plans to expand to accommodate rising cases?

Yes, the Institute hopes to continue to expand not just our clinical services – of which a key aspect is our new Infectious Disease Fellowship – but also our research, awareness, and education efforts.

What are you working on in those areas?

The Institute has a Patient and Program Development Coordinator – also a valley fever patient – who leads our awareness, education, and advocacy programs. For awareness, we are hosting the 2023 Valley Fever Awareness Walk on February 25, 2023. The most recent walk was held in 2019; we have been unable to host since then due to the pandemic. This event provides an opportunity for patients to interact with other patients and also brings awareness to the community. We often receive requests to speak at or participate in community events to help spread awareness even further.

When it comes to education, through a Susan Harwood Grant from the Department of Labor, the VFI offers training to outdoor workers through their employers at no cost. This training is required to be provided annually to construction workers in several California counties, including Kern County.

Finally, for advocacy, the VFI has recently targeted antimicrobial resistance (AMR) and the importance of education, research, and the development of new therapeutics. By linking valley fever with the broader topic of AMR, we have been able to collaborate with a broad community of stakeholders and speak with a louder voice.

Credit : Eric Sonstroem /

The VFI is clearly making progress against valley fever, but it’s not alone in its fight. Researchers from Northern Arizona University and Washington have stated that they aim to create a valley fever vaccine within the next 10 years (3). With the prospect of cases rising across the southern states in the coming decades, it seems wise to adopt a cross-country approach as soon as possible.

A lot lies ahead for California and the southern states when it comes to dealing with climate change-led disease. Joyce has answered some burning questions, but it’s perhaps his shortest answer that carries the most weight. When asked whether he was concerned about the future of climate-led disease, he offered a stoic, yet simple, “Yes.”

Receive content, products, events as well as relevant industry updates from The Pathologist and its sponsors.
Stay up to date with our other newsletters and sponsors information, tailored specifically to the fields you are interested in

When you click “Subscribe” we will email you a link, which you must click to verify the email address above and activate your subscription. If you do not receive this email, please contact us at [email protected].
If you wish to unsubscribe, you can update your preferences at any point.

  1. Scripps Institute of Oceanography, “FAQ: Climate Change in California” (2022). Available at:
  2. NIAID, “Q&A – Why Researchers are Turning Up the Heat on Valley Fever” (2022). Available at:
  3. Northern Arizona University, “Researchers from NAU, Washington tackling an elusive Valley Fever vaccine” (2022). Available at:
About the Author
George Francis Lee

Deputy Editor, The Pathologist

Interested in how disease interacts with our world. Writing stories covering subjects like politics, society, and climate change.

Register to The Pathologist

Register to access our FREE online portfolio, request the magazine in print and manage your preferences.

You will benefit from:
  • Unlimited access to ALL articles
  • News, interviews & opinions from leading industry experts
  • Receive print (and PDF) copies of The Pathologist magazine