diagnosis

Last reviewed 01/2018

• culture and serological testing are the mainstays of diagnosis.
• cultures can be colonised on any artificial medium and after incubation at most temperatures. The colonies grow in three to four days.
• The mycelial form of C. immitis cannot be definitely identified. For identification it requires either conversion to the parasitic form (eg by inoculation into animals) or detection of extracellular coccidiodal antigens produced by the growing fungus in culture.
• in tissue specimens, a mature spherule C. immitis with endospores is pathognomic of infection.
• IgM antibodies are detected temporarily in 75% of patients with primary infection.
• IgG develops later than IgM and generally disappears in several months if the infection resolves.
• IgG tires reflect the course of the disease.
• skin test reactions are positive soon after the development of symptoms of primary infection in the vast majority of patients.