Performance of a New Point-of-care Rapid Test to Diagnose Pulmonary Coccidioidomycosis

In the environment, Coccidioides spp. are distributed in regions with arid soils, low elevations above sea level, and hot summers. Infections occur primarily in the southwestern United States, Mexico, and parts of Central and South America. In southwestern USA, highly endemic regions include the south-central valley of California (‘Valley Fever’) and Arizona. Latent infections occur in dogs and these can reactivate after treatment with immunosuppressive drugs.

Coccidioides spp. (Coccidioides immitis and Coccidioides posadasii) are dimorphic fungi that exist in soil as chains of barrel-shaped arthrospores. The arthrospores are aerosolized and inhaled by animal hosts. This may be followed by localized pulmonary disease or dissemination to the tracheobronchial lymph nodes then other anatomic sites in the face of an inadequate immune response. Infections often follow a pattern of moist conditions (required for growth of Coccidioides spp. in the soil), a dry period, then soil disruption, such as may occur with heavy rainfall, dust storms, or construction.

A diagnosis of coccidioidomycosis is typically confirmed using serology for antibodies to Coccidioides spp., because of the low sensitivity of cytology and the fact that culture is hazardous to laboratory personnel and can have a long turnaround time. Cytologic examination of specimens from affected tissues or body fluids reveals granulomatous or pyogranulomatous inflammation.