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Public Health: Warm weather brings back rare, deadly fungal infection

Blastomycosis is a rare infection caused by a fungus found in moist soil and rotting wood that can lead to serious consequences and even death
A 1965 X-ray showing infiltration of human lungs by a blastomycosis infection.

Public Health Sudbury and Districts (PHSD) is warning the public to be aware of a rare, airborne fungal condition called blastomycosis.

The health unit has issued similar warnings in past years and the condition, according to Health Canada, is known to occur throughout Northern Ontario.

Blastomycosis is a rare infection caused by the fungus Blastomyces dermatitidis. Exposure occurs by inhaling airborne fungal spores or by the fungus entering a scrape or cut, said the news release from PHSD.

An 18-year-old Sault Ste. Marie resident died last summer after contracting the infection. In 2021, an outbreak of infection at Constance Lake First Nation in Northeastern Ontario sickened numerous people and may have led to several deaths.

Farmers, forestry workers, hunters, gardeners and cottagers may be exposed to the fungus if contaminated soil or rotting wood gets disturbed, the release continued.

"This fungus exists in mould form in the environment and in yeast form in human tissue. Blastomycosis is not contagious. There is little evidence of human-to-human transmission, except for rare perinatal or sexual transmission," said the Health Canada Website.

The fungus is found in moist acidic soil in parts of Northern Ontario, Manitoba, Saskatchewan, Quebec, as well as other areas around the Great Lakes and Mississippi Valley. Public Health Sudbury & Districts’ service area is considered an endemic area for the fungus that causes blastomycosis, said the news release.

Although this is a rare infection, PHSD said it is important to take precautions to reduce exposure to the fungus when working in moist soil areas, such as under the house, cottage, porch or shed.

Simple precautions would include wearing work gloves, proper footwear, long pants and long-sleeved shirts, and disposable NIOSH N100 approved HEPA filter dust mask.

The symptoms of blastomycosis can be similar to influenza or pneumonia, and can consist of a persistent cough, muscle aches, joint pain, tiredness, chills, low-grade fever, skin sores and unexplained weight loss, said the health unit.

“Symptoms can present three weeks to almost 4 months after being exposed,” said Adam Ranger, an environmental support officer with the Sudbury health unit. 

“If you have been to an endemic area, and are suffering from any of these symptoms, please let your health care provider know you may have been exposed to the fungus.” 

If the infection is left untreated, blastomycosis may be fatal, said the health unit.


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