FRESNO -- EDITOR'S NOTE: The number of valley fever cases has soared so high in recent years that health experts are calling it "The Second Epidemic." In an occasional series that continues today, the Merced Sun-Star and other members of the new Reporting On Health Collaborative will explore the rise of cases, the tricky science of studying the disease, the high costs to patients and taxpayers, the lack of private interest in funding treatments and vaccines, and the long history of inaction by government agencies. Saturday's report painted the big picture, and revealed that there probably are far more cases than are diagnosed. Today's report delves into the role climate change may be playing in spreading the fungus's footprint outside traditional hot spots. Check out the Sun-Star and mercedsunstar.com in coming weeks for more of this important series.
Valley fever feeds on heat.
And as the average temperature ticks up with each passing decade, experts are concerned that the fungus's footprint and impact are expanding, as evidenced by a rise in cases in areas far outside the hot spots of the Central Valley.
In the soil, the cocci fungus lives on dead organic matter. Less rainfall and higher temperatures reduce overall vegetation, diminishing soil competition for the hardy fungus, scientists say. Cocci spores survive -- even thrive -- when the environment is drier and hotter because other competitors die off.
California State University, Bakersfield, scientists are using satellite images to map areas that could be friendly to the fungus's growth. They're looking for similar vegetation to what is found on Sharktooth Hill, a site for digging up bones from more than 5 million years ago. Because of that digging, researchers often inhaled spores from the soil and came down with valley fever.
So when the team at CSU, Bakersfield, finds areas that have vegetation that mirrors Sharktooth Hill, they paint that part of the map yellow.
Their map shows large swaths of Central California bathed in yellow, mostly undeveloped areas such as those along the Interstate 5 and Highway 99 corridors or areas that have been burned by wildfires. Areas of high vegetation or those paved over typically don't harbor the fungus, explained Jorge Talamantes, a CSU, Bakersfield, physics professor.
"California is becoming drier," he said. "We have some climate changes. I think the environment where the fungus grows will expand."
What Talamantes and other scientists are trying to figure out is whether the fungus itself is moving into new areas or whether it has long been there and is simply waiting for the right conditions to flourish.
Their computer mapping shows vegetation conducive to the fungus's growth farther north and east than valley fever cases normally occur. In theory, the soil near San Francisco would support the fungus's growth, if it didn't rain so much there. If rainfall or temperature patterns change, the reach of the fungus -- and the illness -- could expand farther, CSU, Bakersfield, microbiologist Antje Lauer said.
Still, confirming these scientific theories would require more research funding and many more people working on the problem, she said.
The fever footprint grows
Paso Robles, a favorite spot among wine enthusiasts, tucked into the hills about 30 minutes from the Central California coast, doesn't look like the typical valley fever zone. Bakersfield receives less than 6 inches of rain annually, making it one of the driest parts of the state. Paso Robles averaged 15 inches over the past decade and received more than 20 inches in each of the past two years.