​Infectious Diseases and Microbiology -Blastomycosis (Blastomyces dermatitis)

​Infectious Diseases and Microbiology -Blastomycosis (Blastomyces dermatitis) 
The Blastomycosis
When contaminated soil is disturbed, aerosolized spores, or conidia, are released into the air and can cause blastomycosis. Blastomyces dermatitidis is the source of this disease. The United States' Missouri and Arkansas River basins, as well as the Ohio and Mississippi River valley regions, are endemic for blastomycosis. The source of infection is organic matter-enriched soil. A middle-aged male patient with significant outdoor occupational or recreational exposure is the usual case.

 Fever, sputum production, and chest pain are common symptoms of a symptomatic infection (50 percent of cases). Clinical signs resemble those of histoplasmosis and might be mistaken for lung cancer or tuberculosis. Secondary sites are most frequently the skin (70%), bone (33%), genitourinary tract (25%), and central nervous system (10%) in progressive disseminated blastomycosis.

A mixed inflammatory response involving the infiltration of neutrophils and macrophages as well as the formation of granulomas happens following the inhalation of Blastomyces conidia. Cell-mediated immunity plays a significant role in the process of recovering from infection.

Sputum, exudates, or tissues in a KOH solution can be directly microscopic examined to identify the broad-base budding yeast cells that are characteristic of B dermatitidis. Thermal dimorphism identification takes longer in culture.
Amphotericin B is used to treat life-threatening, disseminated blastomycosis, while itraconazole is used to treat non-life-threatening diseases. Prevention involves avoiding exposure in high endemic areas.