A deadly fungal infection is spreading across the U.S. — and scientists think it’s linked to climate change.

Cases of “valley fever” – which is 10 times more deadly than the flu – have risen 20-fold since the turn of the century.

Caused by the Coccidioides fungus, which releases spores into the air when soil is disturbed, which are inhaled by people, usually construction workers, working on the ground.

The fungus thrives in warm, dry environments and has been called valley fever because 97 percent of cases are found in Arizona and California. But infections have begun to appear in other parts of the country, and experts fear that by 2100 it could be in 17 states.

Its increase occurs in the background increased fear of fungal outbreaksafter the popular HBO apocalyptic show The Last of Us, which shows a fungus that turns victims into zombies.

The Last of Us follows smuggler Joel (right) who accompanies teenager Ellie (left) through Boston, Massachusetts, USA, as a fungus spreads across the world

The Last of Us is set in a world where a fungus is spreading that turns victims into zombies called “clickers” (pictured)

Although valley fever cannot turn a host into a zombie, it can seriously harm some sufferers and kill one in 100 of those infected.

Coccidioidomycosis, or cocci, comes from a fungus that grows in the soil in parts of California and the southwestern United States.

The spore of the fungus rises into the air when the soil is disturbed by wind or digging.

When a person or animal inhales the wounds, the fungus infects the lungs.

Most infections are mild and resolve on their own within days or weeks.

Most people with a mild yeast infection don’t realize it because its symptoms — fatigue, cough, fever, muscle aches, and shortness of breath — mimic those of a respiratory viral infection.

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

But up to ten percent of cases become severe, and recovery takes months.

In these cases, known as disseminated coccidioidomycosis, the disease can spread through the blood 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 meningitis.

According to the Centers for Disease Control and Prevention (CDC), about 20,000 cases of valley fever were reported in 2019.

This is likely an underestimate, the report says, because Valley fever is often misdiagnosed because doctors don’t know enough about it, so patients aren’t even tested for the fever.

About one in 100 people with valley fever die from it each year.

The fungus is endemic to desert parts of the Southwest, and 97 percent of all American cases are found in Arizona and California.

But study in the journal GeoHealth predicted that due to climate change, the endemic region of the fungus would spread northward to include arid western states such as Idaho, Wyoming, Montana, Nebraska, South Dakota, and North Dakota.

With strong warming, this would mean that by 2100, the number of affected states could rise from 12 to 17, and the number of cases could increase by 50 percent.

Valley fever is already difficult to treat, and there is no vaccine against it. Patients may have to take antifungal drugs for months and endure unpleasant side effects such as hair loss and peeling skin.

Scientists have been trying to develop a vaccine against valley fever for decades, but a vaccine tested on humans in the 1980s did not work.

Over the past few years, scientists at the University of Arizona College of Medicine in Tucson have created a vaccine that works in dogs that are also at risk of valley fever.

The USDA may approve a vaccine for dogs by early 2024, which would be the first vaccine to protect against a fungal infection in humans and animals in America.