Valley Fever Research: New Funding Yields New Efforts

Outside of the southwestern United States we may hear little about Valley fever, but now researchers are developing an early warning system to help Arizona residents avoid the fungal infection endemic to the region.

Cases of coccidioidomycosis, or Valley fever, typically occur in parts of Arizona, California, Nevada, New Mexico, and Utah, where the Coccidioides fungus that causes these infections is naturally found in the soil. People can become ill from breathing in the microscopic spores of the fungus, and while some may have no signs of illness others can develop symptoms such as fatigue, cough, fever, shortness of breath, headache, muscle pains, and a skin rash. Such flu-like symptoms can appear within one to three weeks of exposure to Coccidioide spores, and symptoms can take a few weeks to a few months to resolve. More severe cases of Valley fever can last even longer can cause long-term lung problems.

The majority of Valley fever cases occur in Arizona and California, and in 2011 the two states reported 16,467 and 5,697 cases, respectively. That year an additional 237 cases in other states brought the total to 22,641, giving 2011 the highest number of cases recorded from 1998 to 2015. In 2012, a Centers for Disease Control and Prevention (CDC) study found that 3,089 coccidioidomycosis-related deaths took place from 1990 to 2008, with men, individuals aged 65 and older, Hispanics, Native Americans, and residents of California or Arizona at highest risk for dying of Valley fever.

The threat of Valley fever remains largely isolated to states in the Southwest, though the Washington State Department of Health has reported finding the Coccidioides fungus in soil there since 2010 and isolated cases of Valley fever in state residents. In Arizona though, which saw more than 7,600 cases of these infections in 2015, researchers and health officials hope to prevent some cases with a warning system to notify the public when Valley fever is active. The University of Arizona’s Valley Fever Center for Excellence, which works to eradicate the condition, has identified risk factors associated with coccidioidomycosis and found that the disease is most prevalent in Arizona from June through July and from October through November. The fungal spores get kicked up in dust storms and windy conditions, and in areas where Coccidioides spores are endemic to the soil, individuals involved in construction, excavation, agricultural work, archaeological digging, biking, or other activities that disturb soil can become exposed.

University of Arizona researchers are working with state and private partners to identify when the Arizona Department of Health Services should issue warnings to the public about increased Valley fever activity. Using epidemiological evidence to track when more blood tests results come back positive for the infection, health officials can warn local residents of the rise in infections, increasing awareness and potentially preventing new cases. In California’s Kern County, public health officials issued a warning to local residents in September about an increase in Valley fever cases, along with prevention tips on how to reduce the risk of catching it.

At the University of California, Davis, researchers at the Coccidioidomycosis Serology Laboratory are conducting new studies thanks to recent funding from the National Institutes of Health (NIH). At the lab one focus of research is on how genes may make people more or less prone to Valley fever. “One of our goals is to demonstrate the genetic elements that play a large role in determining who has ‘bad coccidioidomycosis’ such as meningitis, while others have a fairly benign course with no long term sequalae,” explains the lab’s medical director, George Thompson, MD, noting that Valley fever research activity is on the rise. “There is a great deal of ongoing work. Our group and one other is working on the human genetics of the disease, a vaccine is currently being developed to potentially prevent infection, new diagnostic tests are in various stages of development, but what we really need are new antifungals.”