If you own a dog that loves to dig holes in wet soil, you may be aware of the dangers of blastomycosis, a fungal infection that can affect the lungs and be fatal if not diagnosed and treated properly.
But did you know that blastomycosis can also infect humans working near wood chips, sawdust or bark piles, such as those often found at pulp and paper mills? Although this disease is about ten times more likely in dogs than in humans, you should know how to minimize the risks of contracting blastomycosis at your workplace.
What is blastomycosis?
Blastomycosis is a fungal infection that was first identified by Thomas Caspar Gilchrist in 1894 and is also known as Gilchrist’s disease. It is caused by inhalation of aerosolized Blastomyces spores from the environment. These fungi are thermally bimorphic, meaning that they occur in two forms depending on temperature: as a mould at ambient temperature or as a yeast at body temperature.
What are the symptoms?
The symptoms of blastomycosis can include fever, chills, headache, coughing and shortness of breath, and the incubation period from inhalation to presentation of symptoms can be 30 to 45 days, making it hard to diagnose.
How can exposure occur in a paper mill environment?
Exposure usually occurs in outdoor areas when warm and moist soil or organic matter containing the fungi is disturbed. The disease is often reported in Northwestern Ontario with an average annual incidence rate of 25–35 cases per 100,000 population, and has also been reported in many areas of Canada and central and southeast U.S., especially near rivers and lakes.
Diagnosis and treatment
Because the symptoms are similar to those of several other conditions such as pneumonia and tuberculosis, diagnosis of blastomycosis can be difficult. The only reliable method is lab culturing of the fungus, which can take 1 to 4 weeks. Once confirmed, antifungal treatment can be applied, but full recovery can take up to 6 to 12 months.
Preventive measures
Here are some activities to consider undertaking to minimize the risk of blastomycosis:
- Dust control: Use dust suppression techniques during processing of biomass to prevent airborne spores.
- Personal Protective Equipment: Use masks or respirators in high-risk areas and gloves if handling soil, wood or hog fuel that may contain fungal spores.
- Storage conditions: Wood and bark should ideally be stored in dry, well-ventilated areas.
- Inspection: Prevent water accumulation in puddles or ditches near stored biomass by ensuring proper drainage.
- Training and awareness: Workers should be informed about the risks of blastomycosis and how to recognize symptoms early. This can be incorporated in safety training.
Martin Fairbank, Ph.D. Martin Fairbank has worked in the forest products industry for 31 years,
including many years for a pulp and paper producer and two years with
Natural Resources Canada. With a Ph.D. in chemistry and experience in
process improvement, product development, energy management and lean
manufacturing, Martin currently works as an independent consultant,
based in Montreal. He is also an author, having recently published
Resolute Roots, a history of Resolute Forest Products and its
predecessors over the last 200 years.
Martin Fairbank Consulting
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