The number of Valley Fever cases in California and the Central Valley has been on the rise since last year, prompting health officials to undertake a campaign to help residents reduce their risk of exposure to the disease.
Valley Fever, also known as coccidioidomycosis, or cocci, is caused by the spore of a fungus that grows in certain types of soil. In California, Valley Fever is most commonly reported in the Southern Central Valley and Central Coast. People get infected by breathing in spores present in dust that gets into the air when it is windy or when soil is disturbed, such as through digging in dirt during construction.
From January through December 2016, 5,372 new cases of Valley Fever were reported to the California Department of Public Health, which corresponds to an incidence rate of 13.7 cases per 100,000 people. The rate is reminiscent of a peak in 2011, when the state saw 5,213 confirmed cases of Valley Fever.
Most infected people will not show signs of illness. Those who do become ill with Valley Fever may have flu-like symptoms that can last for two weeks or more. While most people recover fully, some may develop more severe complications of Valley Fever which may include pneumonia, or infection of the brain, joints, bone, skin or other organs, and has the potential to prove fatal.
"People who live in or travel to areas where Valley Fever is common should take steps to avoid breathing in dusty air," said CDPH Director and State Health Officer Dr. Karen Smith. "If they develop flu-like symptoms, such as cough, fever, or difficulty breathing, lasting two weeks or more, they should ask their doctor about Valley Fever."
Many counties in the Central Valley and Central Coast regions, where Valley Fever is most common, reported an increase in cases in 2016 compared with 2015. The largest number of cases and highest incidence rate in 2016 were in Kern County where more than 2,200 cases, or more than 250 cases per 100,000 people, were reported.
In Stanislaus County, there were 72 recorded cases of Valley Fever in 2016, up from the 50 reported in 2015 and higher than the 58 confirmed during the peak year of 2011.
At this time, health officials do not know why there has been an increase of Valley Fever cases, but they do believe changes in testing, diagnosis and reporting patterns have had an impact.
While anyone can get Valley Fever, those most at-risk for severe disease include people 60 years or older, African-Americans, Filipinos, pregnant women and people with diabetes or conditions that weaken their immune system. People who live, work, or travel in Valley Fever areas are also at a higher risk of getting infected, especially if they work outdoors or participate in activities where soil is disturbed.
A person can reduce the risk of illness by avoiding breathing in dirt or dust in areas where Valley Fever is common. In these areas, when it is windy outside and the air is dusty, stay inside and keep windows and doors closed. While driving, keep car windows closed and use recirculating air conditioning, if available. If you must be outdoors, consider wearing a properly fitted mask (such as an N95 respirator mask which is widely available in retail stores), and refrain from disturbing the soil whenever possible. Employers should train their workers about Valley Fever symptoms and take steps to limit workers' exposure to dust.