Blastomycosis in Dogs

Blastomycosis is a disease caused by the fungus organism Blastomyces dermatitidis, and can result in death if not treated promptly.

How Blastomycosis Is Contracted

The dogs (and humans) most at risk for contracting blastomycosis are those who live or spend time in damp areas where mold is prevalent. Blastomycosis lives primarily in wet or damp areas, such as near swamps or lakes. Hunting dogs seem to be the most common contractors due to their exposure.

All it takes for a dog to contract blastomycosis is inhaling the fungus spores which are hidden in the soil. These fungal spores travel into the lungs and develop there, creating an infection. From there, it spreads into the rest of the body, including the:

  • skin
  • eyes
  • brain
  • testes
  • bones
  • lymph nodes

Symptoms of Blastomycosis

Symptoms for dogs infected with blastomycosis are important to recognize so your dog can receive prompt treatment before permanent damage can be done. Symptoms include:

Due to the lack of appetite, many dogs need to be force-fed for the first 1 to 2 weeks of treatment to ensure proper nourishment is received.

Treatment for Blastomycosis

Dogs typically recover from fungus infections on their own, however blastomycosis is different. Few animals that are exposed are infected, but those that are do require treatment to get better.

  • The standard therapy for many years is called amphotericin B, and is administered through an IV drip or injections rather than in pill form. However, rapid injections to fight the infection are known for doing major damage to kidneys, which are already strained from the blastomycosis to begin with. Improvements are seen in about 3 to 5 days in most cases.
  • The newest and most effective treatment is the administering of a drug called Itraconazole, and it needs to be given for 60 to 90 days. It's an expensive drug, especially for larger dogs that need a higher dosage than small breeds. Itraconazole can run about $300 a month for a 40 pound dog. Improvements are seen in 10 to 14 days.
  • If cost is a problem, or the dog is suffering only a minor case of blastomycosis, Ketoconazole can be used instead. It's never the first choice in treatment, because it has many more side-effects, is more toxic, and less effective than Itraconazole. In terms of cost, Ketoconazole runs about half what Itraconazole does. Improvements are seen in 10 to 14 days.

Preventing Blastomycosis

There is yet to be a vaccine to prevent the infection, and even determining what types of environments the fungus flourishes in can be difficult. It is wise to research your area and see if cases of blastomycosis are common before exposing your dog to that environment. Limit his time in the woods, especially near swamps or water sources.

Blastomycosis cannot be spread from an infected dog to a sick dog or human, so if your dog has contracted the fungus, he will have gotten it from inhaling the spores directly.