Dangerous fungal illness rapidly spreading across country, doctors warn

FILE - An adult male chest x-ray.

Doctors are warning of a dangerous fungal illness rapidly spreading across the country, especially affecting those living or visiting the California and Arizona areas.

If you think it sounds like something from the cutting room floor of "The Last of Us" series, where a parasitic fungal infection devastates mankind, there are some very base-level similarities.

Valley fever (also called coccidioidomycosis or "cocci") is a significant cause of pneumonia, said Dr. Brad Perkins, chief medical officer at Karius, a company that provides advanced diagnostics for infectious diseases.

"This is a fungus," said Perkins, a former Centers for Disease Control and Prevention official who led the anthrax bioterrorism investigation. "Most causes of pneumonia are caused by bacteria. This is a fungus that lives in the soil and is breathed in dusty situations, whether it's a dust storm or around construction or excavation."



FILE - Group of people undergoing the same treatment, sit in a room full of recliners and falls asleep during the hours-long treatment with intravenous antibiotics.  (Brian Vander Brug/Los Angeles Times via Getty Images)

What are the symptoms of Valley fever?

Valley fever and COVID-19 share many of the same symptoms as a cough, difficulty breathing, fever, tiredness or fatigue. In rare cases, it can spread to other body parts and cause severe disease.

Animals, including pets, can also get Valley fever by breathing in fungus spores from dirt and outdoor dust. However, it cannot spread from one person or animal to another. There are about 200 deaths a year due to the disease.

"Those are mostly people with severe immunocompromising illnesses underlying this infection," Perkins said. "It can be a devastating infection in those people. That's pretty rare, fortunately."

Prevention is challenging, according to Perkins. Risk is mostly associated with travel to high-risk areas.

"People concerned about their risk of developing Valley fever should try to avoid dusty situations, mostly in the summer and in peak heat," Perkins said.

You should also see your doctor if you develop signs or symptoms of pneumonia.



FILE - Sand storm and sun, Death Valley, California, USA.  (Marli Miller/UCG/Universal Images Group via Getty Images)

Where is Valley fever found?

The fungi that cause Valley fever are Coccidioides immitis and Coccidioides posadasiii, the CDC reports.

In the U.S., scientists have found C. immitis primarily in California, as well as Washington State. C. posadasii is found primarily in Arizona, as well as New Mexico, Nevada, Utah, Texas, and portions of southern California. 

According to the CDC, Southern California, particularly the southern San Joaquin Valley, and southern Arizona, including metropolitan Phoenix and Tucson, have the highest reported rates of Valley fever. The disease is likely also common in parts of West Texas and along the Rio Grande River. 

In California, state health officials said the number of reported Valley fever cases has greatly increased in recent years – tripling from 2014 to 2018. Most cases of Valley fever in California (over 65%) are reported from the Central Valley and Central Coast regions, the California Department of Health said.

Perkins has a word to the wise for the thousands of football fans traveling to State Farm Stadium, in Glendale, Arizona, for the Super Bowl to see the Kansas City Chiefs take on the Philadelphia Eagles.

"If you're just traveling to the airport and to the hotel and to the Super Bowl, you're probably going to be fine," Perkins said. "If you're out hiking in the desert, you might want to give some consideration to your risk for development of Valley fever."

The Arizona Department of Health Services said 11,523 reported cases of Valley fever was reported in the state in 2020. In total, 94% of cases were reported in 3 counties – Maricopa, Pima and Pinal, which are home to Phoenix and Tucson.



FILE - A man wears a breathing mask while bicycling through Sproul Plaza at UC Berkeley on Friday, Nov. 16, 2018. (Paul Chinn/The San Francisco Chronicle via Getty Images)

Am I at risk for Valley fever?

While most people who breathe in the spores don’t get sick, those who develop Valley fever typically feel better on their own within weeks or months. About 5% to 10% of people who get Valley fever will develop serious or long-term lung problems.

"Many people are asymptomatic when they get this infection, so they don't have any symptoms at all," Perkins said.

Having an infection, however, is probably protective in the future.

"If you're one of the lucky ones that that gets infected and doesn't have symptoms, you probably have some degree of protection in the future," Perkins adds.

If you do develop symptoms, they look pretty much like typical pneumonia caused by bacteria.

"If you see a physician, whether you're hospitalized or as an outpatient, they will likely prescribe medicines that are for bacteria and won't have any impact on this fungus," Perkins said.

Perkins adds that is one way Karius offers the need for a better diagnostic test for diseases like this one, particularly in immunocompromised patients. A single diagnostic test by Karius, using a single blood draw, can identify whether this is a bacterium or fungi of any type and get doctors the information they need and get patients on the right therapy more quickly. 


Why is Valley fever spreading?

The increased number of cases are primarily associated with people migrating to areas like Arizona and California, and people traveling there for recreation, Perkins said.

"Many of those may be retirees or older adults that, one, have not been exposed to Valley fever in the past, and, two, maybe immune suppressed at higher risk for disease," he adds.

The climate crisis may be to blame as well. As heat increases, that may be facilitating the reproduction of the fungus in the soil in these areas. 

"It's important to note that the entire western United States has some level of Valley fever, but it's much higher in the Phoenix region of Arizona and certain parts of the interior of California," Perkins said.

A study published in the journal GeoHealth estimated that the range of Valley fever could reach the border with Canada before the end of the century.

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