Blastomyces spp. initially infect the lungs subsequent to inhalation of infectious conidia, which are found in the environment. There it can cause acute and/or chronic infection. However, many infections remain asymptomatic. In the immunocompromised, severe pulmonary disease and disseminated infection may occur.
When disseminated infection occurs, it most often involves the skin or mucous membranes of the nasopharynx and mouth. Other common sites of disseminated infection include the bones, prostate, and CNS.
Diagnosis can also be made with an antigen test performed on urine or serum.
The image to the right shows the broad-based budding characteristic of Blastomyces.
Image courtesy of the CDC.