Valley fever, the deadly fungal infection spreading across the US 'because of climate change'

A deadly fungal infection is spreading across the US — and scientists believe it is due to climate change.

Cases of 'Valley Fever' - which is 10 times more deadly than flu- have risen 20-fold since the turn of the century.

It is caused by the fungus Coccidioides, which releases spores in the air when soil is disturbed, which are breathed in by people, usually construction workers tending to the ground.

The fungus thrives in warm, dry environments and was dubbed Valley Fever because 97 percent of cases are found in Arizona and California. But infections have begun to crop up in other parts of the country, and experts fear that by 2100 it could be in 17 states.

Its increase comes amid heightened fears about fungal outbreaks, following the hit apocalyptic HBO show 'The Last of Us,' which depicts a fungus that turns victims into zombies. 

While Valley fever cannot turn the host into a zombie, it can cause serious harm to some sufferers and kills one in 100 who contract the infection.

Coccidioidomycosis or cocci originates from a fungus that grows in the soil in some areas of California and the southwestern US.

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 which can cause further disease.

Most infections are mild and clear up on their own within a few days or weeks, and the infection cannot be passed between people or animals. 

Most people with the fungal infection in its milder form will not realize because its symptoms  — fatigue, cough, fever, aching muscles and breathlessness — mimic that of a respiratory virus infection.

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

But up to ten percent of cases 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 meningitis.

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

This is probably an underestimate, it said, as Valley fever has been frequently misdiagnosed because doctors do not know enough about it, so patients are not even tested for the fever.

Around one in 100 people with Valley fever die from it each year.

The fungus is endemic to the desert-like 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 will spread north to include dry western states such as Idaho, Wyoming, Montana, Nebraska, South Dakota, and North Dakota.

In a high warming scenario, this would mean that by 2100 the number of affected states could rise from 12 to 17, while the number of cases could increase by 50 percent.

Valley fever is already tricky to treat, and there is no vaccine for it. Patients might have to take antifungal medication for months and endure unpleasant side effects such as hair loss and scaly skin.

Scientists have been trying to formulate a Valley fever vaccine for decades, but a shot tested in humans in the 1980s did not perform well.

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

The US Department of Agriculture could approve the shot for canines by early 2024, which would be the first one to protect against a fungal infection in humans or animals in America.