Study: Valley Fever a Common Cause of
Community-Acquired Pneumonia
May 10, 2006
From: Janet Stark, (520) 626-7551
Arizona state statistics show that reported cases of valley fever are at record levels. As of the end of April, 2,305 cases of the infection were reported in Arizona, four times the five-year average for the January-April time period and more than 85 percent of the state’s five-year average of 2,732 cases per year.
An online report published in advance of the June 2006 print edition of Emerging Infectious Diseases, a scientific publication of the Centers for Disease Control and Prevention, suggests that these high numbers may represent only the tip of the iceberg.
Lisa Valdivia, MD, and her colleagues at the Valley Fever Center for Excellence at The University of Arizona College of Medicine and Southern Arizona VA Health Care System (SAVAHCS) report that valley fever, or coccidioidomycosis (“cocci”), is responsible for approximately one of every three patients who are treated for what their doctors think is a community-acquired pneumonia. Most of these patients are treated with antibiotics, as if they had a bacterial infection, even though valley fever is caused by a fungus and does not respond to drugs directed at bacteria.
How frequently valley fever actually causes a medically important illness has long been a source of uncertainty based upon previously available information, says John N. Galgiani, MD, director of the Valley Fever Center for Excellence and a member of Dr. Valdivia’s research team. “On one hand, cases of valley fever reported in Arizona in recent years have numbered less than 4,000 infections annually. But other epidemiologic estimates have suggested that this is only one-tenth of the actual number. Dr. Valdivia’s report is the first prospective study looking at this question, and her results support an estimate of about 30,000 patients with valley fever who seek medical care per year, whether or not their physicians make the correct diagnosis.”
Dr. Valdivia, who is in private practice in Tucson, says, “We expect this study to bring new awareness of the prevalence of cocci to people in the primary care field, where patients are being screened.”
The study was conducted at three Tucson sites – the Urgent Care Center at University Medical Center and two medical offices of Arizona Community Physicians.
Mark Wright, MD, clinical assistant professor in the UA Department of Emergency Medicine, medical director of the Urgent Care Center and a member of Dr. Valdivia’s research team, comments, “Most clinicians in this area know about valley fever, but a study never had been done to see how common it really is. It’s a grossly underdiagnosed disease, and doctors need to think about it early, not late.”
Elizabeth Lindberg, MD, also a member of the research team, is an assistant professor in the UA Department of Emergency Medicine and clinical director of the Urgent Care Center. She has a longtime interest in valley fever, and has written about and lectured on the disease. “This study,” she says, “confirmed my belief that there’s a lot of valley fever out there; I always look for it.”
Dr. Valdivia’s study also has major implications for tourists and other recent visitors to the Phoenix-Tucson region, says Dr. Galgiani. He explains that for individuals who develop a pneumonia within a month of returning home from a visit to Southern Arizona, the likelihood that the pneumonia is caused by the valley fever fungus is equally high – basically a one-in-three chance.
“Current professional recommendations for managing pneumonia include seeking a travel history only in patients who do not respond to conventional antibiotics,” he says. “This report provides evidence that it might be preferable for physicians to seek a travel history when the pneumonia is first detected.”
Valley fever is caused by a fungus that lives in the soil of certain areas in the Southwest, Mexico and other regions of the western hemisphere. In Arizona, the most intensely endemic regions are Maricopa, Pinal and Pima counties. Most infections cause respiratory symptoms such as cough, chest pain, and shortness of breath. Other frequent symptoms include muscle and joint pain, skin rashes, weight loss and unusually intense fatigue. These symptoms can last from weeks to many months but usually go away whether or not drug therapy is given. A small proportion of infections leads to much more serious complications, including progressively severe pneumonia. The fungus also may travel through the blood stream from the lungs to other parts of the body such as the skin, the bones or the brain. For these complications treatment usually is needed. Currently available treatments do not cure the infection but assist the immune system to control the growth of the fungus, which results in reduction or elimination of the symptoms while the patient continues treatment. Recurrence of symptoms is common if treatment is stopped.
The University of Arizona is developing a new drug, nikkomycin Z, which has the potential for eliminating the fungus from infected tissue and thereby curing the infection. The Valley Fever Center for Excellence currently is seeking funds to continue clinical trials of nikkomycin Z, but even if the fund-raising efforts are successful, the drug is unlikely to be available for general use for another five to seven years.
In addition to Drs. Galgiani, Wright and Lindberg, Dr. Valdivia’s research team includes Neil M. Ampel, MD, professor of medicine and staff physician, Section of Infectious Diseases, Southern Arizona Veterans Administration Health Care System; T’Prien Stoffer, a medical student at The University of Arizona College of Medicine; and Timothy Fagan, MD, and Donald Lieberman, MD, of Arizona Community Physicians.
The full text of the study, “Coccidioidomycosis as a Common Cause of Community-acquired Pneumonia,” is available at www.cdc.gov/ncidod/EID/vol12no06/06-0028.htm
For more information about valley fever,
please visit www.vfce.arizona.edu
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