Health Hazard Evaluation Report: HETA-2013-0113-3198, January 2014. Evaluation of Coccidioides Exposures and Coccidioidomycosis Infections Among Prison Employees.

摘要

The Health Hazard Evaluation (HHE) Program received a request on behalf of a state correctional and rehabilitation agency and a state correctional health care services agency concerning potential employee exposure to the fungus Coccidioides at two state prisons in California. Coccidioidomycosis, also known as valley fever, is a disease caused by inhalation of spores of a fungus of the Coccidioides species, which grows in the soil in semiarid areas. The prisons are located in counties where the disease is considered hyperendemic. At the time of our evaluation in 2013, staff numbered over 1,300 in prison A and 1,500 in prison B. NIOSH investigators reviewed work and occupational health policies and practices, reviewed medical and work information for the coccidioidomycosis cases among prison employees, interviewed a convenience sample of 172 prison employees about their work practices and exposures, and looked at the ventilation systems in buildings where more employees worked such as clinics and offices and some inmate housing units. We identified 103 confirmed cases of coccidioidomycosis among prison employees over a 4 1/2-year period (January 2009-June 2013). The crude average annual incidence was 1,039 cases per 100,000 employees for prison A and 511 cases per 100,000 employees for prison B over this time. However, we do not know if each confirmed case of coccidioidomycosis among prison employees was due to an exposure at work or outside of work. Interviews with employees revealed that they may be potentially exposed to Coccidioides in the outdoor work environment through soil disruption activities, being present during dust storms, and other outdoor activities. Employees may also be potentially exposed to Coccidioides during outdoor activities outside of work. Neither the written respiratory protection plans nor the aerosol transmissible diseases exposure control plans specifically discuss exposure to Coccidioides. Most of the offices and clinics were air-conditioned, temperature and relative humidity measurements were within established guidelines, and an adequate amount of outdoor air was being provided. However, some prison areas had airflow patterns that could result in entrainment of unconditioned outdoor air. Environmental control measures such as wetting soil before it is disturbed, maintaining grass on exercise yards, stabilizing soil, paving roads, improving building ventilation, and changing work practices (such as reducing time spent outdoors) would be expected to reduce dust exposures to varying degrees. However, none of these measures will eliminate exposure to Coccidioides, and their relative effectiveness in reducing occupational coccidioidomycosis is unknown.