Valley fever, a fungal lung infection caused by *Coccidioides* spores lurking in dry soil, is spreading well beyond its traditional strongholds in Arizona and California’s Central Valley — and the first genuinely new drug to fight it in nearly four decades is now in late-stage clinical development. The drug, olorofim, works through a completely different mechanism than the azole antifungals doctors have relied on since the late 1980s, and early trial results show sustained clinical responses in roughly 73 percent of patients treated for a full year. For the millions of people now living in areas where the fungus is newly establishing itself, that pipeline matters more than it ever has.
California recorded nearly 12,500 valley fever cases in 2024 — the highest number the state has ever reported — and 2025 is already running ahead of that pace. The fungus has been detected as far north as south-central Washington state, and experts project that half of the United States could become endemic territory within a few decades. This article breaks down why the infection is moving into new regions, what olorofim could mean for treatment, who is most at risk, and what the spreading geography of valley fever means for brain health — because disseminated coccidioidomycosis can reach the central nervous system, causing a form of meningitis that is particularly dangerous for older adults and immunocompromised individuals.
Table of Contents
- Why Is Valley Fever Spreading to States That Have Never Seen It Before?
- How Valley Fever Reaches the Brain — and Why That Matters for Dementia Care
- Olorofim — The First New Valley Fever Drug in Nearly 40 Years
- How Olorofim Compares to Current Valley Fever Treatments
- The Diagnostic Problem — Why Valley Fever Is Still Missed So Often
- Construction, Agriculture, and Environmental Exposure Risks
- What the Next Decade Looks Like for Valley Fever
- Conclusion
Why Is Valley Fever Spreading to States That Have Never Seen It Before?
The short answer is climate. *Coccidioides* thrives in a specific weather pattern: wet winters that allow the fungus to grow deep in the soil, followed by hot, dry, windy summers that crack the earth and launch spores into the air. As climate change pushes that wet-then-dry cycle into regions that were previously too cool or too consistently moist, the fungus follows. The organism has now been detected in south-central Washington state, hundreds of miles north of where it was historically found, and in California, cases have spread from the Central Valley into Sacramento, Stanislaus, San Joaquin, Monterey, and Santa Barbara counties. Arizona has seen a parallel shift. A February 2025 CDC Morbidity and Mortality Weekly Report documented sharp regional increases in valley fever incidence across Arizona counties from 2005 to 2022, with cases rising dramatically in areas where the disease was previously rare.
California’s numbers tell a similar story of acceleration: the state saw an 800-plus percent increase in infections between 2000 and 2018. Between April 2023 and March 2024 alone, California provisionally reported 10,593 cases — a 40 percent jump over the prior year. Models project a 50 percent rise in valley fever cases nationally by 2100 if warming trends continue, which means this is not a temporary spike but a long-term geographic expansion. The practical consequence is that physicians in states like Washington, Oregon, and parts of the upper Midwest may start encountering a disease they were never trained to recognize. Valley fever symptoms — cough, fever, fatigue, joint pain — mimic pneumonia, flu, and COVID-19, so misdiagnosis is common even in endemic areas. In new territory, delayed diagnosis becomes almost guaranteed, and delay is what allows the infection to disseminate to bones, skin, and the brain.
How Valley Fever Reaches the Brain — and Why That Matters for Dementia Care
When valley fever stays in the lungs, most healthy people recover without treatment. The danger comes when the infection disseminates, spreading through the bloodstream to other organs. Coccidioidal meningitis — infection of the membranes surrounding the brain and spinal cord — is the most feared complication, and it is almost always fatal without lifelong antifungal treatment. The current standard of care for coccidioidal meningitis is high-dose fluconazole, often continued indefinitely, because stopping treatment frequently leads to relapse. For people already living with dementia or cognitive decline, this creates a cruel overlap.
The symptoms of coccidioidal meningitis — confusion, headache, personality changes, difficulty with concentration — can be mistaken for worsening dementia rather than recognized as a treatable infection. Caregivers and clinicians in newly endemic areas need to consider valley fever in the differential diagnosis when a patient with known cognitive issues shows sudden deterioration, especially if that patient has spent time in the Southwest or in any of the expanding endemic zones. However, it is important not to overstate the risk. Disseminated valley fever occurs in a small minority of cases — roughly 1 percent of infections spread beyond the lungs. The people at highest risk for dissemination include those with weakened immune systems, people taking immunosuppressive medications (common in older adults with autoimmune conditions), pregnant women, and individuals of Filipino or African descent, who face higher dissemination rates for reasons that are still not fully understood. If you or someone you care for falls into a high-risk group and lives in or has traveled to an endemic area, the threshold for requesting a coccidioidomycosis blood test should be low.
Olorofim — The First New Valley Fever Drug in Nearly 40 Years
No new antifungal treatments for valley fever have been approved in the United States in close to four decades. doctors have been working with the same limited toolkit: fluconazole and other azole antifungals for mild to moderate cases, and amphotericin B — sometimes called “ampho-terrible” for its severe side effects — for life-threatening infections. That is why the development of olorofim, a drug created by the biotech company F2G, has generated real attention in the infectious disease community. Olorofim works by blocking pyrimidine biosynthesis through inhibition of fungal DHODH, an enzyme essential for building the DNA and RNA that fungi need to reproduce.
This is a completely novel mechanism of action — it attacks the fungus through a pathway that existing antifungals do not touch, which means it can work against strains that have developed resistance to azoles. The drug has received FDA Orphan Drug Designation for coccidioidomycosis, FDA Breakthrough Therapy Designation, and Qualified Infectious Disease Product designation for multiple fungal infections, all of which are intended to speed its path through the regulatory process. Clinical trial results published in 2025 showed a partial clinical response in 68.3 percent of patients at day 42, with that number holding at 65.9 percent at day 84. Complete clinical response was achieved in 7.3 percent. More importantly, favorable clinical responses were sustained in 73.2 percent of patients through a full year of treatment, and the drug demonstrated fungicidal effects — meaning it kills the fungus rather than simply stopping its growth — both in laboratory and animal studies, with low minimum inhibitory concentrations against *Coccidioides* species.
How Olorofim Compares to Current Valley Fever Treatments
Fluconazole remains the workhorse for valley fever treatment. It is oral, generally well-tolerated, and effective for most pulmonary and soft-tissue infections. But it has real limitations. Some patients do not respond, relapse rates after stopping treatment are significant, and fluconazole penetrates certain tissues — including bone — poorly. For coccidioidal meningitis, patients typically face a lifetime on the drug, with periodic monitoring for liver toxicity and other side effects. Amphotericin B is more potent but must be given intravenously, causes kidney damage, and is physically brutal for patients to tolerate.
Olorofim offers several theoretical advantages: an entirely different mechanism of action (useful when azole resistance is suspected or confirmed), oral administration, and fungicidal rather than merely fungistatic activity. The sustained one-year response rate of 73.2 percent in clinical trials is encouraging, particularly for patients who have failed or cannot tolerate existing therapies. However, olorofim is not yet approved, and the trial populations have been relatively small. It is also unclear how the drug will perform specifically in coccidioidal meningitis, where the blood-brain barrier complicates drug delivery, and where the stakes of treatment failure are highest. The realistic near-term scenario is that olorofim will initially serve as a second-line or salvage therapy — a critical option for patients who are not responding to fluconazole or who cannot tolerate amphotericin B. Whether it eventually displaces azoles as a first-line treatment will depend on larger trials, long-term safety data, and cost. For now, its importance lies in ending a nearly 40-year drought in antifungal development for a disease that is becoming more common every year.
The Diagnostic Problem — Why Valley Fever Is Still Missed So Often
One of the most frustrating aspects of valley fever’s expansion is that the diagnostic tools exist, but physicians outside endemic areas simply do not think to use them. A blood test for coccidioidomycosis antibodies is widely available, and more sensitive PCR-based tests are increasingly common. The problem is clinical suspicion. Studies have found that in endemic areas, patients see an average of four physicians and wait months before receiving a correct diagnosis. In states like Washington, where the fungus is only now being detected, that delay will be worse. For older adults, the diagnostic challenge is compounded by symptom overlap with other conditions common in aging. Chronic cough gets attributed to heart failure or COPD.
Fatigue and weight loss suggest cancer. Confusion points to dementia. Joint pain reads as arthritis. A valley fever test is rarely on the list unless the clinician has specific experience with the disease or the patient volunteers a travel history to an endemic area — and many patients do not realize that Sacramento or Bakersfield now qualifies. The warning here is straightforward: if you or someone in your care has unexplained pneumonia, chronic cough, fatigue, or neurological symptoms, and there is any history of time spent in the western United States, ask for a coccidioidomycosis test. This is especially important for people with weakened immune systems, including those on corticosteroids, chemotherapy, or biologic drugs for autoimmune conditions. A missed valley fever diagnosis does not just delay appropriate treatment — in disseminated cases, it can allow the infection to reach the brain, where the consequences are devastating and often irreversible.
Construction, Agriculture, and Environmental Exposure Risks
Valley fever is fundamentally a disease of disturbed soil. The people at greatest occupational risk are agricultural workers, construction crews, archaeologists, and anyone whose work involves digging, grading, or moving earth in endemic areas. California’s Central Valley — the nation’s most productive agricultural region — sits squarely in the highest-incidence zone, and prison inmates at facilities in endemic counties have historically faced elevated rates.
Solar farm construction in the desert Southwest has also been linked to outbreaks, as large-scale land clearing sends plumes of *Coccidioides*-laden dust into the air. For retirees who have moved to Arizona or the inland valleys of California — a common pattern for people seeking warm, dry climates — the risk is real but manageable. Avoiding outdoor activity during dust storms, keeping car windows closed on windy days, and using N95 masks during yard work or gardening in endemic areas are all practical steps. There is no vaccine for valley fever, though several are in development, so prevention remains a matter of limiting spore inhalation.
What the Next Decade Looks Like for Valley Fever
The trajectory is clear: more cases, in more places, with a medical system that is only beginning to adapt. If olorofim receives FDA approval, it will be the most significant therapeutic advance for valley fever since fluconazole was introduced in the late 1980s. Several vaccine candidates are also in preclinical and early clinical stages, though none is likely to reach the market before the end of this decade. Meanwhile, climate models suggest the endemic zone will continue expanding northward and eastward.
For the dementia care community, the takeaway is that valley fever belongs on the radar in a way it never has before. Coccidioidal meningitis is rare, but it is treatable if caught — and it is catastrophic if missed. As the fungus moves into new states and the population of older, immunocompromised adults continues to grow, the intersection between valley fever and brain health will become more relevant, not less. Staying informed about the geographic spread, knowing when to push for testing, and understanding the treatment pipeline are all part of responsible care planning.
Conclusion
Valley fever is no longer a regional curiosity confined to the deserts of Arizona and California’s Central Valley. With nearly 12,500 cases in California in 2024, the fungus detected in Washington state, and projections that half the country could become endemic within decades, this is a national health issue in the making. The development of olorofim — the first new antifungal mechanism for this disease in nearly 40 years, with sustained responses in over 73 percent of trial patients — offers genuine hope for better treatment, particularly for patients who fail standard therapy. For those focused on brain health and dementia care, the key action items are awareness and advocacy.
Know that valley fever can mimic and worsen cognitive decline. Know that a simple blood test can identify the infection. Know that the endemic map is expanding, and that travel or relocation history matters more than it used to. And know that the treatment landscape, while still limited, is finally evolving. Asking the right questions — of doctors, of caregivers, of yourself — is the single most important step in catching this infection before it reaches the brain.
