If you suspect your pet has symptoms of blastomycosis, consult with your family veterinarian or local animal emergency hospital right away.
Blastomycosis is a systemic fungal disease that affects dogs, cats, and even affect humans. It is caused by Blastomyces dermatitidis, which lives in rich, wet, sandy, acidic soil predominantly near river valleys.
Contracting Blastomycosis
Although blastomycosis cannot directly spread from a pet to a human, humans are at risk of contracting it from the environment. Construction and excavation workers are often at higher risk due to their frequent occupational contact with soil.
For pets, blastomycosis is contracted when a pet inhales the fungal spores, typically while digging in dirt. Here are a few quick facts:
- Dogs are 10x more likely to be affected than humans
- Dogs are 100x more likely to be affected than cats
- Young, large breed dogs are most affected (due to being out hunting or running through the woods)
- Blastomycosis is more common following heavy rains and within ½ – 1 mile of water
Map from the Minnesota Department of Health’s website.
In the United States, blastomycosis is more common in the Mississippi, Ohio, Tennessee, and Missouri River valleys, as well as near the St. Lawrence River. Unfortunately, since blastomycosis is more common near water, this makes dogs living in the Land of 10,000 Lakes (and many rivers) particularly at risk! There have been confirmed cases across Minnesota, mostly in the Northeastern part of the state and the Twin Cities area. According to the Minnesota Department of Health’s 2022 data, 341 dogs and 3 cats had confirmed cases. You can view more data on their website here.
Common Signs
Signs can appear weeks to months post-exposure. Most commonly, the lungs are affected, and dogs show signs such as:
- Coughing
- Weight loss
- Exercise intolerance
- Difficulty breathing
Other signs include:
- Limping
- Eye issues
- Non-healing wounds
Blastomycosis can also affect your dog’s skin, eyes, brain, bones, lymph nodes, and other tissues. Visceral organs such as the heart and liver may also be affected, but this is less common.
Diagnosis
To diagnose blastomycosis, your dog’s veterinary team will perform:
- X-rays of the lungs
- Bloodwork
- Urine tests
- Tissue samples to look for the fungus
Treatment
Sadly, this is a profoundly serious disease and can be fatal in almost half of cases. Often, treatment involves:
- 1-2 weeks of hospitalization. Pets who are very sick will receive IV fluids, oxygen support, and other medications until stable enough to be treated at home
- Ongoing at-home treatment, including:
- Months of antifungal medications
- Pets can experience relapse if these medications are stopped too soon
- Pets often get worse immediately after starting treatment because the fungal organism dies, causing inflammation
- Frequent rechecks with your family veterinarian to assess the efficacy of the treatment and to monitor for side effects from the antifungal medications
- Months of antifungal medications
If blastomycosis is not treated promptly & properly, it is often fatal.
Unfortunately, there is no vaccination or practical way to prevent blastomycosis. Additionally, there is no current way to test soil for the Blastomyces species. The best thing pet parents can do is to immediately consult with your family veterinarian if you have any concerns or notice symptoms. Routine exams and diagnostics are also important to stay ahead of the disease – after all, it’s easier to treat blastomycosis before it spreads and becomes more advanced!
More Reading:
- Zoonotic Diseases in Dogs and Cats
- Camping & Hiking with Your Dog | Part II: Safety Tips
- Oxygen Kennels at the ER Vet
Written by Jess Brown, DVM.
