- culture and serological testing are the mainstays of diagnosis. (1,2,3)
- 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 coccidioidal 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.
Initial investigation of all patients should also include a chest x-ray. This may show a variety of findings, including single or multilobe consolidation, mass, nodules, or occasionally miliary infiltrates with or without cavities. (1)
References
- Crum NF, Lederman ER, Stafford CM, et al. Coccidioidomycosis: a descriptive survey of a reemerging disease. Clinical characteristics and current controversies. Medicine (Baltimore). 2004 May;83(3):149-75.
- Hage CA, Carmona EM, Epelbaum O, et al. Microbiological laboratory testing in the diagnosis of fungal infections in pulmonary and critical care practice. An official American Thoracic Society clinical practice guideline. Am J Respir Crit Care Med. 2019 Sep 1;200(5):535-50.
- Centers for Disease Control and Prevention. Fungal diseases: clinical testing guidance for coccidioidomycosis, histoplasmosis, and blastomycosis in patients with community-acquired pneumonia. Nov 2023 [internet publication].