The CDC has reported a dramatic increase in valley fever in several southwestern states from 1998 to 2011.
“It’s difficult to say what’s causing the increase,” Benjamin J. Park, MD, chief epidemiologist with the CDC’s Mycotic Diseases Branch, said in a press release. “This is a serious and costly disease and more research is needed on how to reduce its effects.”
Using data from the National Notifiable Diseases Surveillance System, the CDC analyzed the incidence of valley fever (coccidioidomycosis) from 1998 to 2011. They found that the incidence increased from 5.3 cases per 100,000 population in the endemic area in 1998 to 42.6 cases per 100,000 population in 2011. The endemic area includes Arizona, California, Nevada, New Mexico and Utah.
According to the report in Morbidity and Mortality Weekly Report, valley fever is caused by inhalation of the soil-dwelling fungus Coccidioides. Patients with the disease typically only experience an influenza-like illness, but some develop severe pulmonary disease. Less than 1% of patients have disseminated disease. More than 40% of patients with valley fever require hospitalization at some point.
“Valley fever is causing real health problems for many people living in the southwestern United States,” CDC Director Tom Frieden, MD, MPH, said in a press release. “Because fungus particles spread through the air, it’s nearly impossible to completely avoid exposure to this fungus in these hardest-hit states. It’s important that people be aware of valley fever if they live in or have traveled to the southwest United States.”
Although more research is necessary to determine exactly why the incidence of valley fever has increased, it could be related to changes in weather, higher numbers of new residents or changes in the way the disease is detected and reported, according to the press release.