If you’ve been following the news lately, you may have heard whispers—or perhaps alarm bells—about a mysterious, fast-spreading fungus making its way across the American West.

It’s not the plot of a sci-fi thriller, but a real and growing health concern.

What was once considered a rare condition has now become a widespread problem, growing at a pace that few expected.

For older adults, the risk is especially troubling, making awareness more important than ever.


Valley Fever, known to doctors as coccidioidomycosis, is caused by a fungus called coccidioides.

This fungus lives in the soil of dry, dusty regions—think California’s Central Valley, Arizona’s deserts, and other parts of the Southwest.

When the soil is disturbed by wind, construction, or even gardening, the fungus releases tiny spores into the air. Breathe them in, and you could be at risk.


For decades, Valley Fever was a regional oddity, mostly affecting people in Arizona and California.

But now, experts are sounding the alarm: cases are skyrocketing. In California alone, reported cases have soared by more than 1,200% in just 25 years.

In the first half of 2025, over 5,500 cases were already reported—on track to shatter last year’s record of nearly 12,500.

Arizona isn’t faring much better, with more than 14,000 cases in 2024, up 27% from the previous year.

Nationwide, Valley Fever is on pace to hit nearly 30,000 reported cases in 2025. And here’s the kicker: the CDC estimates the real number could be 10 to 18 times higher, with as many as 360,000 Americans infected each year.


So, what’s behind this dramatic rise? Experts point to a perfect storm of environmental factors, with climate change leading the charge.

Wet winters followed by hot, dry, and windy summers create ideal conditions for the fungus to thrive and spread.

As the climate warms, the “fungus zone” is creeping northward, threatening to make Valley Fever a problem in up to 17 states by the end of the century.

Dr. Shaun Yang, a leading microbiologist at UCLA, puts it bluntly: “Climate change is the main reason to explain this type of dramatic explosion. This kind of very wet and dry pattern is perfect for this fungus to grow.”


While anyone can get Valley Fever, certain groups are more vulnerable to severe illness.

This includes people over 60, those with weakened immune systems, pregnant women, and individuals of African or Filipino descent.

For most, Valley Fever causes mild, flu-like symptoms and often resolves on its own.

But for about 10% of cases, the infection can become severe, lasting for months and sometimes spreading to other parts of the body—including the brain, skin, and liver.


Valley Fever can be sneaky, often masquerading as a stubborn cold or pneumonia. Here’s what to look out for:

• Fatigue and weakness
• Persistent cough
• Fever and chills
• Shortness of breath
• Muscle aches and joint pain
• Night sweats
• Red rash (often on the legs, but sometimes on the chest, arms, or back)

If you’ve been feeling under the weather for more than a week—especially after spending time outdoors in dusty areas—don’t brush it off.

Valley Fever can be misdiagnosed, so it’s important to mention your travel and exposure history to your healthcare provider.


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Most people recover fully, but for some, Valley Fever can be life-altering or even fatal. Each year, about 200 deaths are attributed to the disease.

In rare cases, the infection spreads beyond the lungs, causing a condition called disseminated coccidioidomycosis. If it reaches the brain, it can cause meningitis—a life-threatening emergency.

There’s no vaccine (yet) and no guaranteed cure. Mild cases often resolve with rest and supportive care.

For more serious infections, doctors may prescribe antifungal medications, but these can have significant side effects and aren’t always effective.

Research is ongoing, and there’s hope on the horizon: the University of Arizona is working on a vaccine, with promising results in dogs that could one day translate to humans.


Also read: This once-wiped-out virus is making a dangerous comeback—and health officials say the risk is real

While you can’t eliminate the risk entirely, there are steps you can take to protect yourself:

• Avoid outdoor activities in dusty conditions, especially in high-risk areas like California’s Central Valley and Arizona.
• If you must be outside, wear an N95 mask or similar respirator to filter out spores.
• Keep windows and doors closed on windy days.
• Use air purifiers indoors if you live in or visit endemic regions.
• Wet down soil before gardening or digging to reduce dust.

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Have you or a loved one experienced Valley Fever? Do you have tips for staying safe in dusty environments? Are you concerned about the impact of climate change on your health?