A fungal infection that most commonly occurs in America’s Southwest region is projected to expand further throughout the country due to climate change in the coming decades.
A fungus that is endemic to the Southwest is capable of causing an illness known as Valley fever -- named after the San Joaquin Valley in California. The disease, also known as coccidioidomycosis, is caused by breathing in spores of either the Coccidioides immitis fungus or Coccidioides posadasii fungus.
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These fungi are found in the soil in Arizona, Nevada, Utah, New Mexico, California, Texas and Washington, according to the Mayo Clinic. However, most cases of Valley fever are reported in Arizona and California each year, the CDC says.
Cases have been rising slightly in the past decade, with more than 20,000 Valley fever infections reported in 2019 -- though experts believe that’s an underestimation of the actual number of cases. For most people who become infected, the illness is mild and may cause few or no symptoms, so those cases may go unreported.
Symptoms of the initial form of Valley fever might include a fever, cough, tiredness, headache, chills, muscle aches and pains, rashes and more. Learn more about Valley fever symptoms here.
Valley fever causes more serious illness in about 5%-10% of cases, leading to chronic, and potentially deadly, forms of coccidioidomycosis. Serious cases most often occur in people with weakened immune systems, experts say.
Is Valley fever contagious?
Both people and dogs are susceptible to Valley fever infection, especially those spending time outdoors in areas where the fungus coccidioides are present. Living in the soil -- and able to survive the heat and drought -- the fungi’s spores “can be stirred into the air by anything that disrupts the soil, such as farming, construction and wind,” which people can then breathe into their lungs, the Mayo Clinic says.
Experts say that most people who breathe in the spores don’t get sick.
However, for those who are fans of HBO’s new show “The Last of Us,” in which a contagious fungal infection sends the world into a deadly pandemic, it’s important to note: Valley fever is not really contagious between people or between people and animals. The CDC says that the illness “can’t spread from the lungs” between people and animals.
In some “extremely rare” cases, though, the illness could reportedly spread through a wound infection or through an organ transplant with an infected organ.
The CDC says scientists have been working on a vaccine for Valley fever since the 1960s, but no such vaccine exists yet. In fact, there aren’t any existing vaccines in the U.S. that protect against fungal infections in humans or animals.
However, “researchers at the University of Arizona College of Medicine in Tucson have developed a vaccine that’s highly effective in dogs,” NBC News reports. This vaccine, which could be approved for dogs as early as 2024, would be the first vaccine of its kind.
Related: You seriously need to start watching ‘The Last Of Us’ on HBO
Spreading to other regions
Studies show that more and more fungal infections are being diagnosed outside of their usual regions, causing some concern for areas that aren’t familiar with, prepared for, or have immunity of such infections. Researchers predict that an illness like Valley fever could spread more north and east due to climate change.
In a GeoHealth study published in 2019, researchers suggest that Valley fever infections will start rising through the Great Plains through 2035, and then more north and west by 2065, and then exist in pretty much the entire western half of the country by 2095.
Obviously, that is a long ways away -- but experts are hoping to build on the momentum they have now to develop vaccines for fungal infections.
“I think fungi are really the coming superbugs. I think they’re really the ones that are going to be problematic over the next decade. And Valley fever is going to be a key part of that,” Dr. George Thompson of the University of California, Davis told NBC. “They are really here to stay. This battle is sort of just beginning.”
For now, those of us in Michigan aren’t really at risk of getting infected with Valley fever, unless we travel to states or countries where the fungi is present.
The CDC’s map below shows where they estimate the fungi that causes Valley fever to be present. Note: The fungi are also present in Mexico and parts of Central and South America, where illnesses are also said to occur.