The Centers for Disease Control and Prevention confirmed in a new research article Thursday what doctors, epidemiologists and people who suffer from valley fever have experienced firsthand: Cases of the fungal disease rose at stunning rates over the last decade, especially in California and Arizona.
The CDC’s analysis addresses the findings reported in Just One Breath, a series of news stories on valley fever by the Reporting on Health Collaborative published in various news outlets, including Voice of OC. The series chronicled the rise in valley fever cases and deaths and the lack of attention by state and federal policymakers.
“I do think that the reporting series helped to put [valley fever] at the forefront, especially in California,” said Dr. Benjamin Park, medical officer in the CDC’s Mycotic Diseases Branch and the study’s senior author.
People catch coccidioidomycosis, also known as valley fever, after inhaling fungal spores that are common in the dry parts of the Southwest as well as Mexico and Latin America. Experts say the lack of funding and serious attention to valley fever has stalled efforts to combat the disease.
But valley fever seems to be gaining policy attention. House Majority Whip Kevin McCarthy, R-Bakersfield, and CDC Director Dr. Tom Frieden recently met to discuss valley fever’s impact in the Southwest.
"We discussed the possibility of developing a vaccine and also developing various strategies to combat this disease through better diagnosis, treatment and prevention, and I commend Dr. Frieden's willingness to accept the invitation I made for CDC officials to come to Bakersfield to improve awareness and meet with our local valley fever experts and our medical community,” McCarthy wrote in an email.
Frieden also declared in an email that his agency is “committed to continuing to work together to address this serious and costly disease.”
Frieden also wrote that he is looking forward to welcoming McCarthy on a visit to the CDC in April to meet with the agency’s valley fever experts and tour facilities.
To better understand valley fever’s toll, the CDC analyzed data from the National Notifiable Diseases Surveillance System for the years from 1998 to 2011.
“What was surprising to me was that these increases [in valley fever] have been very consistent year over year,” Park said. “Overall, the trend, I think, is quite striking, and it clearly shows that there is an increasing burden.”
The findings, published Thursday in the CDC’s Morbidity and Mortality Weekly Report, mirror much of what the Reporting on Health Collaborative found, including:
- The total number of valley fever cases rose by more than 850 percent in the areas where valley fever is most common — California, Arizona, Nevada, New Mexico and Utah. In California, the case counts rose from 719 in 1998 to 5,697 in 2011.
Cases in Arizona increased from 1,474 in 1998 to 16,467 in 2011.The study noted that a change in a major Arizona lab’s reporting practices could account for part of Arizona’s increase.
In states where the disease is not as common, the number of valley fever cases reported jumped from six in 1998 to 240 in 2011.
- For the entire period, a total of 111,717 coccidioidomycosis cases were reported to the CDC from 28 states and the District of Columbia. The CDC found that 66 percent were reported from Arizona and 31 percent from California.
- Because cases can incease simply as a result of the population increasing, the CDC also tracks the rate of the disease in the population, known as the incidence. The incidence of reported valley fever grew eightfold from 1998 to 2011, rising in the areas where valley fever is common from 5.3 per 100,000 people to 42.6 per 100,000, the article stated.
- The rise of valley fever occurred across all age groups. The rate of the disease was highest among 40- to 59-year-olds in California, but in other states the incidence was higher among people 60 and older.
The study includes several caveats about its findings, noting that artificial increases in cases could be spurred by changes in how states monitor the disease and increases in the number of people being tested for valley fever.
But the study also notes that a 2006 study found only 2 to 13 percent of patients with signs and symptoms were tested for valley fever, indicating that the disease is likely greatly underreported.
“The problem is we don't really know what the underreporting rate is, but it's substantial,” said Dr. Royce H. Johnson, professor of medicine at UCLA and chief of infectious disease at Kern Medical Center.
Michael Lancaster, director of laboratory services at the Kern County Public Health Services Department, said the various factors mentioned in the article could add up to a bit of an increase but that “we're probably in reality seeing more valley fever.”
The study also notes a lack of data about race and ethnicity. Higher valley fever rates have been shown among blacks and Asians, and blacks are at greater risk for developing the most serious form of the disease, the study says. But the study says that about 70 percent of cases were missing details about race and ethnicity.
Valley fever experts said the numbers prove that the disease is a public health concern worthy of research dollars. Better diagnostics, medications and a vaccine to fight the disease cannot be achieved without more money, they said.
Industry and government funding for valley fever research has dried up, Johnson said. “There are many, many diseases getting more funding that are less important than this one,” Johnson said, noting the personal and financial cost of failing to address the growing problem of valley fever.
CDC’s Park said the study’s findings provide a strong argument for development of better treatments for valley fever so people suffering from the disease can resume their normal lives sooner and stay out of the hospital.
“Clearly more research is warranted and is needed,” he said.
Misdiagnosis of valley fever is common. Doctors and public health officials stressed that educating physicians and the public in general to identify valley fever symptoms is crucial because the disease is difficult to prevent.
“Because fungus particles spread through the air, it's nearly impossible to completely avoid exposure to this fungus in these hardest-hit states,” Frieden wrote. “It's important that people be aware of valley fever if they live in or have traveled to the southwest United States."
Clarisse Tsang, acting infectious disease epidemiology program manager for the Arizona Department of Health Services and an author of the CDC study, said people should learn valley fever symptoms and ask their doctors to test them for the disease if they are suffering from a cough, fever and fatigue.
Physician awareness matters beyond Arizona and California, experts said. Doctors should examine patients’ travel histories to learn whether patients have journeyed through areas where valley fever is endemic.
Valley fever will continue to be a public health issue as more people who have not been exposed to the disease travel to areas where the fungus is common, Lancaster said.
“It's going to become an even worse problem,” he said.
The Reporting on Health Collaborative involves The Bakrsfild Californian, the Merced Sun-Star, Radio Bilingue in Fresno, The Record in Stockton, Valley Public Radio in Fresno and Bakersfield, Vida en el Valle in Fresno, the Voice of OC in Orange County and ReportingonHealth.org. The collaborative is an initiative of The California Endowment Health Journalism Fellowships at USC's Annenberg School for Communication and Journalism.