Although the meningitis outbreak has captured the headlines this week, another fungal infection – coccidioidomycosis – racks up an estimated 150,000 new cases in the U.S. each year, researchers reported.
Men, people older than 64, Hispanics, Native Americans, and the immunocompromised are most at risk of dying from the infection, which is endemic to the desert areas of the Americas, Frank Sorvillo, PhD, MPH, of the UCLA Fielding School of Public Health, and colleagues wrote in the November issue of Emerging Infectious Diseases.
“The number of deaths from coccidioidomycosis might be greater than currently appreciated,” according to the researchers, who analyzed coccidioidomycosis-related mortality – more than 3,000 deaths – over an 18-year period.
They added that the number of deaths, as well as related healthcare costs, will likely increase as the population of older and immunosuppressed individuals grows.
“Effects of increasing healthcare costs associated with coccidioidomycosis have been observed in coccidioidomycosis-endemic states; almost half of the reported case-patients are hospitalized and make multiple visits to emergency rooms and outpatient facilities during the course of the illness,” Sorvillo and colleagues wrote.
Coccidioidomycosis is caused by inhalation of the spores of the soil fungus Coccidioides immitis or C. posadasii. The fungi are typically found 4 to 12 inches below the surface in areas of low elevation that receive less than 20 inches of rain per year.
Among people living in areas where the fungi are endemic, 10% to 50% have been exposed, and even one spore can cause symptoms.
Although most infected individuals do not develop symptoms, infection can lead to disease similar to a respiratory or pneumonia-like febrile illness. Infection can be severe or fatal.
Although there are coccidioidomycosis-related deaths each year, there is little detailed information on mortality from the disease.
To explore the issue, Sorvillo and colleagues examined death certificate data from the National Center for Health Statistics spanning 1990 to 2008. The certificates contained a cause of death and a list of conditions believed to have contributed to death.
During the study period, there were 3,089 coccidioidomycosis-related deaths in the U.S., for an age-adjusted rate of 0.59 per million person-years.
The researchers attributed the greater mortality risk among older individuals to declining immune function and greater numbers of comorbidities.
The higher risk among men was attributed a greater risk of severe pulmonary and disseminated coccidioidomycosis and a greater likelihood of exposure through their occupations. Archaeologists, military personnel, construction workers, and farmers have been shown to have an elevated risk of exposure.
Hispanics and Native Americans are believed to have a higher risk compared with other ethnic groups because of the greater concentration of these populations in areas where the fungi are endemic, including California and Arizona, the two states most affected by the disease.
Certain conditions were more likely to be seen on the death certificates of people with a coccidioidomycosis-related death than on those of people with another cause of death, including the following:
- Vasculitis (OR 6.55)
- Rheumatoid arthritis (OR 6.51)
- Systemic lupus erythematosus (OR 4.17)
- HIV infection (OR 3.92)
- Tuberculosis (OR 2.82)
- Diabetes (OR 2.12)
- Chronic obstructive pulmonary disease (OR 1.45)
- Non-Hodgkin lymphoma (OR 1.44)
Source reference: Emerging Infectious Diseases by Huang J, et al “Coccidioidomycosis-associated deaths, United States, 1990-2008″ Emerg Infect Dis 2012.