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When Katie Thoele decided to take her six-year-old Miniature Pinscher Bruiser for a weekend of hiking in Wisconsin, she never anticipated the dangers lurking while Bruiser enjoyed the outdoors. Bruiser spent the weekend doing what he loved most— playing by the water, chasing chipmunks, and laying in the sunshine. It wasn’t until two weeks later when Bruiser started showing physical symptoms of illness, and four days later he died due to respiratory failure. Bruiser gained his wings July 9, 2010 after being taken by the disease known as Blastomycosis.
What is Blastomycosis?
Blastomycosis is a serious systemic fungal disease. It is caused by the fungus Blastomyces dermatitis that grows near water such as lakes, streams, beaver dams and other habits where soil is moist, acidic, and rich in decaying foliage. Most blastomyces spores will die unless the conditions are ideal for the fungus to survive. This explains why blastomyces are found in small pockets instead of being widespread, often making it difficult to find in the environment.
Who is at risk?
While humans can often become infected, dogs are 10 times more likely to develop the disease. Although it primarily infects dogs, humans and cats, it has also been reported in a wide variety of animals such as horses, ferrets, deer, wolves, African lions, bottlenosed dolphins, and sea lions. Blastomycosis is generally limited to North America, and most cases have occurred in Mississippi, Missouri, Tennessee, and Ohio River basins. Individuals and dogs that spend much of their time in the woods, swamps, or near water have a greater risk of infection. One study in Wisconsin has shown that 95% of infected dogs live within 400 yards of a body of water. Sporting and hunting dogs are therefore more commonly infected because of their frequent exposure to the soil and wet areas. When the ground where the fungus lives is disturbed, the infectious spores found in the soil are released into the air. Dogs often acquire infection by inhaling the spores through their nose which then travel down into the lungs where it induces a respiratory infection.
Clinical Findings & Symptoms:
When the respiratory defenses are overwhelmed, the disease spreads through the bloodstream from the lungs to other organs throughout the body to involve the eyes, brain, bones, lymph nodes, skin, and tissues just beneath the skin. According to Merck Veterinary Manual signs of pulmonary involvement are seen in up to 85% of affected dogs. Lymph node and skin involvement are reported in about 50% of affected dogs. Signs of ocular blastomycosis are seen in 30-50% of affected dogs and can include blindness, glaucoma and retinal detachment. Lameness associated with severe paronychia occurs in about 25% of affected dogs. Involvement in the central nervous system (CNS) is uncommon, occurring in
After exposure, some dogs may be infected but not show clinical signs for weeks or even months, and if left untreated can be fatal. The clinical symptoms of blastomycosis may vary with organ involvement which can include coughing, skin lesions, anorexia, depression, fever, weight loss, shortness of breath, exercise intolerance, enlarged lymph nodes, eye disease, or lameness.
The most common choice of treatment used for infected dogs and cats, is the antifungal drug Itraconzole. For aggressive cases, especially those with evidence of hypoxemia, combination treatment with Amphotericin B and Itraconzole is recommended under close veterinary care. Itraconzole should be given daily for a minimum of two months and continued until the disease is no longer noticeable. In treated dogs, clinical cure can be expected in ~70% of the dogs, with ~20% suffering relapses months to a year after treatment. Prognosis is best for dogs with mild or no lung disease, but is poorest for those with CNS involvement.
Although Bruiser struggled with some unrelated medical issues throughout his life, blastomycosis became his silent killer. The infection hid in his system two weeks before symptoms were apparent. He was quickly diagnosed and treated with medication, but it proved to be too late and his body couldn’t handle the recovery. After losing her best friend it has been Katie’s mission to inform pet owners and lovers of the risks to help save the lives of other beloved companions everywhere.
The Merck Veterinary Manual (9th ed.). (2005). Philadelphia, PA: MERCK & CO., INC., pp.518-519.
Drs. Foster & Smtih; Blastomycosis in Dogs & Humans. Veterinary & Aquatic Services Department.
In this podcast we are wrapping up our “Old Dogs Rule” educational series with a difficult, but important conversation about end of life care. We are very fortunate to feature Dr. Kathleen Cooney, founder of “Home to Heaven,” an in-home pet hospice and euthanasia services practice. She is also the owner of the first-ever pet euthanasia center in the United States. The center is located on her 35-acre farm in Loveland, Colorado and offers two comfort rooms for pet euthanasia. It is open year-round for families looking for an alternative to standard clinic or in-home euthanasia. Dr. Cooney graduated from the Colorado State University College of Veterinary Medicine in the spring of 2004. That same spring, her family had to say goodbye to their 15-year-old yellow lab, McKenzie. McKenzie passed peacefully under the aspen tree in their front yard. From this experience, Dr. Cooney learned just how important it was for pets to be at home for the end of their lives. In 2012, she completed writing the book “Veterinary Euthanasia Techniques: A practical guide.” Dr. Cooney served on the 2013 American Veterinary Medical Association's panel on euthanasia guidelines. She is currently the Vice President and conference coordinator for the International Association for Animal Hospice and Palliative Care (IAAHPC). She travels frequently to speak on her work and on the current advancements in end-of-life care.
This podcast was made possible thanks to the generous support of the Kenneth A. Scott Charitable Trust, A KeyBank Trust.