Blastomycosis: report of three cases from Alberta with a review of Canadian cases

Approximately 120 cases of blastomycosis have been reported from Canada to-date. The great majority of these occurred in the Eastern provinces. Since 1970, three cases of blastomycosis have been seen in Alberta. The first case, with meningeal and pulmonary involvements, was diagnosed at post-mortem. The second case was that of a 75-year-old male with a history of pancytopenia, aortic arteriosclerosis, exposure to mercury, and fever. KOH and periodic-acid schiff (PAS) stained smears of the lung tissue, received after autopsy, showed numerous budding yeast cells of Blastomyces dermatitidis along with some hyphal filaments. Similarly, budding cells of B. dermatitidis and hyphal segments were observed in large numbers in the PAS and Gomori's methenamine-silver (GMS) stained sections made from adrenals, lung, kidney, and spleen tissues. Attempts to culture the fungus on a variety of selective and non-selective media were unsuccessful, due to heavy bacterial contamination. The indirect fluoroscent antibody results were 2+ with the B. dermatitidis conjugate. The third case was that of a 31-year-old male, who was admitted to the hospital with the chief complaint of chest pain. Biopsy tissue sections, stained with the GMS procedure revealed a few foci with B. dermatitidis yeast cells. The immunodiffusion and complement fixation (CF) tests gave positive results against B. dermatitidis antigen (titre, 1:16). The CF titre declined following treatment with amphotericin B and the immunodiffusion test became negative after the institution of antifungal therapy. Except for the last patient, the other two patients had no history of travel in any known endemic areas. In addition to these cases, a survey of blastomycosis occurring in this country has been presented along with on the disease in dogs and a cat.