Thousands of Americans have contracted an incurable fungus on the West Coast being dubbed a new ‘epidemic’. 

Valley Fever, named due to the concentration of cases in Arizona and California, is a severe lung infection with a mortality rate of one in every 100 infected individuals.

In just 25 years, cases have climbed more than 1,200 percent in California. 

For the first six months of 2025, there were more than 5,500 provisional cases reported in the state. 

Health experts say if cases continue at the same rate, they will surpass last year’s high of nearly 12,500. 

In Arizona, there were over 14,000 reported incidents of Valley Fever in 2024, rising from 10,990 cases in 2023, indicating an increase of more than 27 percent.

Nationwide, Valley Fever cases are now at a record high and set to reach almost 30,000 for 2025. 

The infection stems from the coccidioides fungus, which discharges spores into the air when soil is disturbed. Health professionals are advising people to steer clear of dusty outdoor areas to prevent inhaling the spores.

Thousands of Californians have been struck down by incurable fungus on the West Coast dubbed ‘new American epidemic’

The number of Valley Fever cases peaked for the first time in a decade in 2021.  

The 20,970 recorded instances were the most on record for a single year since the last peak in 2011.

Instances declined in 2022 but picked back up last year, and experts are concerned over an expected surge of the fungus in the coming decades. 

The CDC estimates Valley Fever could infect more than half a million Americans each year in the future.

The agency said that due to rising temperatures across the globe, the endemic region of the disease will spread north to include dry western areas. 

Other experts fear that it could be endemic in 17 states by 2100. 

California Department of Public Health director Dr. Erica Pan stated: ‘California experienced a record year for Valley Fever in 2024, and so far, the numbers are high in 2025. Valley Fever is a significant illness that persists in California.’

‘We encourage Californians, visitors to the state, and their healthcare providers to monitor signs and symptoms of Valley Fever for early detection.’

There is no person-to-person transmission of the disease, for which there is currently no preventative vaccine.

Valley Fever can often resolve on its own without treatment.

For more severe or persistent cases, antifungal medications are used to manage symptoms and prevent the infection from worsening or spreading.

Experts caution that Valley Fever can be overlooked by physicians or mistaken for pneumonia, given its similar symptoms, including fatigue, cough, fever, muscle aches, and difficulty breathing.

Other symptoms include night sweats, joint aches and a red rash, usually on the legs but occasionally on the chest, arms and back.

As the disease is often underdiagnosed due to mild symptoms, the CDC estimates that the true burden is around 206,000 to 360,000 cases per year – 10 to 18 times more than reported. 

The fungus spore is whipped up into the air when the soil is disturbed by the wind or digging. When humans or animals breathe in the spores, they travel through the respiratory tract and into the lungs where they reproduce

But up to 10 percent of infections become severe and take months to recover from.

In these cases, known as disseminated coccidioidomycosis, the disease can spread through the bloodstream to other parts of the body, including the brain, skin and liver.

If it infects the membranes and fluid around the brain it can cause life-threatening meningitis.

To prevent the disease from reaching advanced stages, Dr Pan advises: ‘If you have been sick with symptoms like cough, fever, trouble breathing, and tiredness for more than seven to ten days, please talk to a healthcare provider about Valley fever, especially if you’ve been outdoors in dusty air in the Central Valley or Central Coast regions.’ 

On average, there were approximately 200 coccidioidomycosis-associated deaths each year from 1999 to 2021. 

Research suggests the rise and spread of Valley fever may be linked to changes in climate. 

Wet winters after droughts help the fungus grow, and dry, windy weather in the following summer and fall can help the fungus get into the air. 

Shaun Yang, the director for molecular microbiology and pathogen genomics at the UCLA Department of Pathology and Laboratory Medicine, told SFGate: ‘I think climate change is the main reason to explain this type of dramatic explosion.

The infection was dubbed Valley Fever because 97 percent of cases are found in Arizona and California

‘I don’t think anything else can explain this type of phenomenon. This kind of very wet and dry pattern definitely is perfect for this fungus to grow.’

There is no proven treatment for Valley Fever and patients are usually prescribed rest and given therapies to manage symptoms.

Doctors may prescribe antifungal medications, but there is no evidence from clinical trials that show these treatments are effective – and antifungal drugs come with the potential for serious side effects.

In 1996, the Valley Fever Center for Excellence at the University of Arizona, was established in order to address the problems caused by the coccidioides fungus. 

Two-thirds of all Valley Fever infections in the US occur in Arizona, mostly in the urban areas surrounding Phoenix and Tucson. 

Last year, the University of Arizona Valley Fever Center for Excellence secured $33 million from the National Institute of Health to pursue a vaccine. 

Its director, Dr John Galgiani, helped develop one for dogs THAT is still undergoing licensing for commercial marketing. But it is hoped the VACCINE could translate to humans.

‘I’ve been thinking about a human vaccine all along but taking this through the dog is really a very useful step to show proof of the concept, making the idea of taking it to humans that much more attractive,’ Mr Galgiani said.