Blastomycosis: a new endemic focus in Canada

Area of Science:

• Medical Mycology
• Infectious Diseases Epidemiology

Background:

• Blastomycosis is a fungal infection caused by Blastomyces dermatitidis.
• Endemic areas for blastomycosis are primarily in the United States and Canada.

Purpose of the Study:

• To identify new endemic foci of Blastomyces dermatitidis in Ontario.
• To analyze diagnostic delays and patient outcomes for blastomycosis.

Main Methods:

• Retrospective survey of patients with positive Blastomyces dermatitidis cultures between 1970 and 1981.
• Analysis of patient residency, diagnostic methods, and survival rates.

Main Results:

• A new endemic focus was identified north and east of Lake Superior, with 20 of 27 traceable patients residing there.
• Blastomyces dermatitidis was detected in 90% of cases via direct microscopy.
• Average diagnostic delay was 15 weeks due to lack of clinical awareness; diagnosis was made at autopsy in two cases.
• Approximately 80% of patients survived.

Conclusions:

• The Lake Superior region represents a significant endemic area for blastomycosis.
• Clinical awareness of blastomycosis is crucial to reduce diagnostic delays.
• Blastomycosis has a high survival rate when diagnosed and treated.