The Deadly Valley Fever Epidemic Is Getting Worse in the American Southwest

By John Upton

When Pauline moved to Arizona with her husband, the couple was oblivious to the fungal maelstrom engulfing their new subdivision. Construction workers and street sweepers kicked up the desert dust around them—dust that was invisibly laden with the spores of a killer.

The Coccidioides fungus that Pauline inhaled shortly after moving into her Phoenix house commonly resides in soils of the American Southwest. Infection, called coccidioidomycosis, doesn't produce symptoms in many cases. But when it does, the infection—also known as valley fever—can eat away at its victim’s insides, occasionally leading to death.
The debilitating affliction has reached epidemic proportions in the Southwest, with infection rates rising at least tenfold in the last 15 years. This week, a two-day valley fever symposium was held in Bakersfield, California, to discuss the growing problem, which made headlines earlier this year following outbreaks in California's overcrowded prisons.
"My real big impression from the two days has been what a heavy burden (Valley fever) is for individuals," said Dr. Thomas Frieden, director of the Centers for Disease Control and Prevention, according to the Fresno Bee. "It really brought home to me just how serious the problem is."
Pauline, who requested that I withheld her last name for privacy reasons, said her symptoms began less than a year after she moved into the dusty neighborhood in 2009. She became hopelessly ill, unable to work.
“I started to feel tired all the time and developed a dry cough that wouldn’t go away,” Pauline said. “My joints started to ache and I had bad headaches and a hoarse voice."

Micrograph of coccidioidomycosis, also known as valley fever. Image via Wikimedia

Her general practitioner initially diagnosed it as an upper respiratory infection, and prescribed azithromycin, a common antibiotic that isn't effective against fungal infections. When that didn't work, she was prescribed another round of treatment.
"I coughed and hacked my way through September and October, but I didn’t return to the doctor because they weren’t doing anything to help," she told me. "I used every over-the-counter remedy for coughing I could find, but nothing helped. I was in so much pain in my joints and the cough was so severe by the end of October that I couldn’t speak more than a few words without choking.”
Doctors in the West got their first inkling of the disease in the 1930s and 1940s, when thousands of new Californians settled in the Central Valley, driven west to escape drought-wrecked prairielands that had devolved into the infamous Dust Bowl. It’s also when World War II delivered soldiers, prisoners of war and interned Japanese Americans to some of the fungus's most fertile breeding grounds. Valley fever took hold among the unfortunate new arrivals.
But then the disease lolled and was largely ignored by the medical establishment, which came to regard the occasional infection as an exotic disease. Now it’s “reemerging,” to borrow from bureaucratic parlance, and its range appears to be growing. More than 22,000 cases were confirmed in the US in 2011—up from 1,200 in 1995. Between 1990 and 2008, 3,089 deaths linked to the disease were documented.

Distribution of valley fever in the Southwest, via the CDC

Research published last month in the journal Emerging Infectious Diseases concluded that valley fever hospitalization rates more than doubled in California between 2000 and 2011, with medical costs exceeding $2 billion during that time. The CDC suspects that as many as 150,000 people who are infected annually don’t seek treatment or aren’t properly diagnosed.
“We’ve been sounding the alarm since 2002,” said Sharon Filip, a valley fever survivor who set up a support group and helped write books to draw attention to the Coccidioides, also known simply as cocci, scourge. She says she’s constantly being contacted by patients who can’t get good advice from their own doctors. Like Pauline, Filip’s case was initially misdiagnosed as a bacterial infection—a story she says she hears repeated by many who reach out to her. “We’re fighting an uphill battle," she said.
Most people exposed to cocci remain perfectly healthy. Some ail for a while with flu-like symptoms while their body builds up its defenses. An unlucky few are overwhelmed by a fungal perfusion that permeates nearly their entire body, triggering such deadly complications as meningitis and pneumonia. Drugs are sometimes prescribed and some patients receive surgery, but deaths are tragically common.
“There are some drugs,” said John Taylor, a University of California at Berkeley mycologist who has researched the disease and its evolutionary history. “But they’re hard on you, and although they prevent the spread of the fungus they don’t kill it. There’s much to be desired in the treatment of bad cases of cocci.”
For the majority of patients, cocci produces few, if any, symptoms, and often a single infection can produce lifelong immunity. But recent transplants to the Southwest don't have any such immunity, and those transplants with weakened immune systems, as well as the elderly, are the most likely to die from it. Construction work, archeology, and farming are particularly dangerous trades in cocci-infected regions, which stretch from Mexico up through California; from Texas to Utah. Patches of Argentina are also affected.
Anything that kicks up dust increases the hazards. Taylor said Californian dust storms in the 1970s blew spores north to infect Oregonians and west to San Francisco. A surge of valley fever cases struck down Northridge residents after a 1994 earthquake hit the Los Angeles neighborhood.

This CDC graph shows the growth in reported valley fever cases. Tens
of thousands more go unreported every year, according to the CDC.

To avoid contracting the disease, it’s best to avoid breathing dust. Steps like staying inside during dust storms and monsoons can help. So does driving with the windows rolled up. But in the deserts of America’s Southwest, there is no escape from the dust—meaning there can be no escape from the pathogens that it harbors.
Fortunately, valley fever is not contagious from human to human. That’s because of the lifestyle that this strain of cocci evolved as it shed the genes that coded for plant-digesting enzymes, replacing them with those that allow it to slurp up animal tissue. Some fungi in the Coccidioides genus have now evolved to prey on animal hosts, including the two species that cause coccidioidomycosis—Coccidioides immitis and Coccidioides posadasii.
Normally, they eek out lives as filaments called hyphae. The hyphae live in the soil and produce spores, a lucky few of which get sniffed into the lungs of desert rodents. The spores balloon in size inside the host, forming spherules. The mammal immune system kicks quickly into gear at this point, building walls around the spherules, containing them and developing immunity against further attacks.

“There’s an influx of naïve hosts. They’re now putting homes outside the cities in more rural areas, where they’re disturbing the desert.”

It’s when the immune system fails to contain these spherules that the fungus can propagate throughout its victim, sometimes with deadly consequences. As an infected rodent dies, collapsing into the desert, the cocci burst out of suspended animation and unleash streamers of hyphae that eat the rotting meat. As the fungus feasts, hyphae and spores slip back into the soil, ready to start the cycle all over again. Because humans killed by the fungus are generally embalmed or cremated, they largely don't propagate the Coccidioides life cycle.
“If a cocci spore gets into a human, it has made a big mistake,” Taylor said. “It might kill us but it’s not going to reproduce inside us—because they’re going to burn you or embalm you. It won’t get a chance to reproduce. It’s unlikely to ever become adapted to living in humans.”
The reasons for the rise in valley fever cases are not entirely clear. Climate change, with the flood-drought cycles it is bringing, could be helping the fungus to flourish in damp soil before launching the spores when drought arrives. The changing climate is also shifting the ranges of its natural prey, including small mammals, which release spores into the soil when they die. And as they move, they're likely to bring cocci with them.
The growing rate of diagnoses does reflect a growing awareness among doctors of the disease and its symptoms. People are also increasingly moving out of cities and into dusty exurbs, migrating into regions that are rich with cocci. “There’s an influx of naïve hosts,” Taylor said. “They’re now putting homes outside the cities in more rural areas, where they’re disturbing the desert.”

By John Upton 3 days ago

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