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Hot, Dry Winds Help Spread Deadly Valley Fever Infections

June 26, 2013 at 12:00 AM EDT
In the Mojave Desert, extreme heat and wind made worse by more intense weather conditions in recent years has helped the spread of a resilient fungus that causes a deadly infection known as Valley Fever. Ray Suarez reports on the role of dust in the dramatic rise of Valley Fever.

GWEN IFILL: Next: an often undiagnosed disease known as valley fever is spreading throughout the Southwest.

Ray is back with our science story.

RAY SUAREZ: The Mojave Desert is known for extreme heat and fierce wind. Recent years of hotter and drier seasons have only intensified those conditions. Drivers sometimes need headlights to navigate through thick dust storms.

You might think of a blast of gritty breeze as uncomfortable, rather than threatening, but Westerners have good reason to worry about what that wind is carrying.

ANTJE LAUER, Biologist: This is a good spot. Looks real interesting, soil.

RAY SUAREZ: Biologist Antje Lauer is at the desert’s western edge, the NASA Dryden Center to study one tiny local inhabitant she suspects is actually benefiting from prolonged drought, a microscopic fungus called coccidioides, or cocci.

ANTJE LAUER: They adapted to desert soils. So they can tolerate high temperatures and they can tolerate higher pHs. That’s unusual for Fungi. Usually, Fungi like lower pHs.

So, I take a sample a little deeper from the soil, because I want to find a site where it is actually growing, and not just have been blown into.

RAY SUAREZ: While a continued drought may be good news for the cocci fungus, it’s very bad news for humans, because this fungus can be deadly. All it takes is a gust of wind.

When the fungus becomes airborne, it’s easily inhaled. Once in moist lungs, it can cause an infection called valley fever. That infection can cause illness ranging from flulike symptoms to severe pneumonia, even death. Valley fever is not contagious, and it’s not new to people who live in California and Arizona deserts, particularly those who work outside.

But the CDC reported this March that the number of valley fever cases in endemic areas soared between 1998 and 2011 from 2,000 to over 24,000.

ANTJE LAUER: We have about 900 percent increase in valley fever cases, and people try to speculate why that is the case.

And one hypothesis that I’m pursuing is that the drought is actually favoring, or the continuous drought is favoring any spore formed in the soil, which includes the valley fever fungus, and outcompetes all the microorganisms that are not easily forming spores.

RAY SUAREZ: While Antje Lauer looks at the cocci’s ability to thrive in dry soil, scientist Vic Etyemezian, from the Desert Research Institute, explores the role of dust in valley fever’s dramatic rise.

VIC ETYEMEZIAN, Desert Research Institute: Valley fever is very much a — sort of a dust-related event. So, you can imagine if you have much more abundant areas where valley fever spores can be suspended into the air, then you can imagine that the exposure for people could potentially go up in the future.

RAY SUAREZ: Etyemezian and a colleague move a measuring device propelled by a baby jogger across the rutted desert landscape.

VIC ETYEMEZIAN: What we’re doing is measuring the potential for wind erosion and the potential for dust emission at different equivalent wind speeds. So we’re trying to understand if the wind is blowing at, say, 35 miles an hour, which of these areas is most susceptible to — to dust becoming airborne?

And this instrument we have is something like a wind tunnel. It’s a very compact version of a wind tunnel, and that’s exactly what it does. It simulates higher wind speeds and, as the wind speed gets higher, you measure the dust, and you can kind of figure the dust climatology.

RAY SUAREZ: The scientists are part of a bigger project funded by NASA to study possible impacts of climate change on NASA centers. Climate change is not the only suspect in the increased illnesses.

You also have to take into account the human footprint on the land. These days, the deserts sprout subdivisions, shopping centers, and oil derricks, and every time you disturb the land you can release the cocci spores into a stiff wind like this one, and they can fly as far as 75 miles.

At the edge of the desert in fast growing Bakersfield, California, infectious disease specialist Dr. Royce Johnson, an expert on valley fever, says anyone can get sick, even if you just drive through a desert area.

DR. ROYCE JOHNSON, Infectious Disease Specialist: All you have to do is take a breath at the wrong time. It will impact your lower lung, and the infection starts from there, and can spread anywhere it wants in your body. If you roll down the window driving from San Diego to Seattle, you could catch cocci while you’re driving through, no question. That could happen, and it has happened.

RAY SUAREZ: Dr. Johnson says so little is known about valley fever, it is still unclear why reactions to the infection are so varied.

ROYCE JOHNSON: Most people in fact will successfully fight off the infection, and have no symptoms, and have lifelong immunity from it.

About 40 percent of the people that are infected get a flulike illness.

RAY SUAREZ: For a small fraction of the population, people like Al Rountree, the condition can be life-threatening. His lungs became so inflamed, he was put on breathing machine in the intensive care unit.

AL ROUNTREE, Suffered from Valley Fever: I thought I was dying. That first weekend, I — I mean, I thought for sure. I have been sick a lot, but nothing like — I have never been this sick in my life. I have been — like I said, I have had a lot of things happen, but I have never been this sick in my life. And it’s just — it’s devastating.

RAY SUAREZ: Now, after months of intensive infusion of an antifungal drug that is very tough on the body, Rountree is finally on the mend.

ROYCE JOHNSON: So, we will transition you to an azole oral drug and probably be treating you for the next three years or so.

RAY SUAREZ: Al Rountree’s infection was confined to his lungs. Valley fever is most dangerous when the fungus spreads, or disseminates. That condition is often fatal. Since 1990, more than 3,000 people have died.

ROYCE JOHNSON: If it goes to your brain and produces meningitis, that can kill you by a variety of mechanisms. It can also kill you if it goes through the bloodstream, and goes back to your lung, and you get respiratory failure. You can end up on a ventilator in the ICU.

And then it can also kill you sort of like cancer does. You can just waste away from having a lot of disease, and not being able to control it.

RAY SUAREZ: While people with weaker immune systems are more vulnerable, it is not known why some healthy individuals can get just as sick.

ROYCE JOHNSON: So then this thing bursts open and these little babies come out.

RAY SUAREZ: Dr. Johnson says much of the general public and many physicians have never heard of valley fever, leading to patients going untreated as the disease worsens or getting treatment for the wrong illness.

ROYCE JOHNSON: I tell my medical students that they will know more than 99.9 percent of all the physicians that ever lived about this disease.

RAY SUAREZ: Higher-profile diseases, like West Nile virus, receive 20 times as much in federal funding, even though more people get sick from valley fever.

ROYCE JOHNSON: West Nile virus came to the United States in New York City, one of the world’s most famous metropolises. It also has multiple medical schools, but New York City, Bakersfield, Tucson, maybe not equivalent in terms of international notoriety. I think resources were put together because of where this virus landed.

RAY SUAREZ: Antje Lauer agrees.

ANTJE LAUER: There are no valley fever cases, and there is no incidents of coccidioidomycosis on the East Coast, where all the politicians are sitting, so they are never reading anything in the news about valley fever around Washington. So they are not that concerned.

RAY SUAREZ: There’s a lot more scientists say they must know about cocci spores: how they grow, where they blow, as the tiny spore makes more Americans sick.

JEFFREY BROWN: And a postscript to Ray’s report: This week, a federal judge ordered the California Department of Corrections to transfer 3,000 more inmates at high risk of contracting valley fever. Attorneys say 18 inmates have died in the past two years from complications related to the disease. The state has 90 days to move them from two prisons located in the San Joaquin Valley.

Online, you can find the CDC’s list of 10 things that you should know about valley fever, including symptoms of the disease and other important information.