What is Blastomycosis in Dogs?

What is Blastomycosis in Dogs?

Author WDF Staff


Humans and dogs can experience many similar health issues. In fact, there are bacteria, viruses, and fungus that can infect both species. One of these cases where both humans and dogs can get an infection is called blastomycosis. This fungal infection is a threat to our dogs and us. If you think you or your dog might be at risk, or you already got your diagnosis and want to know more, here are the most essential information about blastomycosis in dogs.

What is blastomycosis in dogs?

Blastomycosis is a disease. More precisely, it is a fungal infection caused by the Blastomyces dermatitidis fungus. This irritating fungus can infect our dogs and settle in their respiratory system, where it will start multiplying. If the infection is left untreated, it can spread throughout the body and infect organs. The infection can be very dangerous, and without treatment, it can be fatal.

How can my dog contract blastomycosis?

Most fungal infections are contracted similarly. The fungus resides in nature, and when the dog inhales the infectious spores, they can contract the disease. This is particularly dangerous for dogs because they have their noses close to the ground. Dogs sniff their environment, and since they have a lot stronger sense of smell than we do, it is one of their primary ways to pick up information from their surroundings.

aussie shepherd

Where can dogs get infected?

It is interesting to learn that scientists are still trying to isolate the fungus in the “wild.” They were unsuccessful in isolating it from the environment, but fortunately, they know where most cases occur. Based on the blastomycosis data and cases, scientists and veterinarians made a list of places where the fungus is most likely to infect humans and dogs. Here are the areas in which you should be extremely careful;

  • Ohio
  • Missouri
  • Tennessee
  • St. Lawrence River valleys

Less likely, but cases were still reported;

  • Middle Atlantic States
  • Quebec
  • Ontario
  • Manitoba
  • Southern Great Lakes

Of course, fungi need specific conditions to thrive. They require moist places that will allow them to reproduce and thrive. It is no wonder this fungus survives in river valleys, swamps, and other warm, damp places.

How is blastomycosis diagnosed?

This infection is not that common, so your vet might not think of it as soon as you take your dog for an exam. In most cases, dog owners notice something wrong with their dogs and take them for an examination. To successfully diagnose blastomycosis, the vet needs to perform a thorough check of the dog. There are three main ways to diagnose this infection;

  • Cytology - Vets can microscopically examine cells by obtaining them from liquids oozing from open wounds or extracting them from lymph nodes or nodules.
  • Histopathology - The vet might order a biopsy, where they will examine cells from a specific tissue.
  • Antigen test - Your vet can perform an antigen test where results are pretty conclusive. However, it is mainly performed if the dog is already suspected of having blastomycosis.

black dog in meadow

There are other ways to potentially diagnose this infection, like agar-gel immunodiffusion (blood test), but it can lead to inconclusive results. If this test returns positive results, it doesn’t mean the dog actually has blastomycosis; it only means they were exposed to the organism.

Blastomycosis symptoms

The critical thing to a successful treatment is early detection. If you know how to spot the symptoms early, your dog has a better chance of surviving this terrible infection. The most common blastomycosis symptoms are;

  • Weight loss
  • Loss of appetite
  • Troubled breathing
  • Fever
  • Depression
  • Lethargy
  • Skin lesions
  • Sudden blindness (fungus can infect the eyes)
  • Coughing
  • Seizures
  • Testicular inflammation
  • Enlarged lymph nodes

How is it treated?

The most important thing dog owners want to know is, “How is blastomycosis treated?” The good news is the disease is treatable. However, not all dogs will survive the disease or treatment. The survivability is anywhere from 50 to 75%, and the critical period is 24 - 72 hours after the first drug administration. The vet will perform an x-ray of the infected dog’s lungs to determine how severe the infection is. After that, they will prescribe different antifungal medications. The most common antifungal agents vets prescribe are fluconazole and itraconazole, with the latter being preferred for dogs.

golden-retriever happy

The main issue with treating blastomycosis is that most of these fungi reside in the lungs. After the drug is administered, most of them start to die. That will trigger a severe inflammatory response, and that is when the treatment can take a bad turn. Severe respiratory issues can occur, and in worst cases, lung failure can happen. It is crucial you notice symptoms of blastomycosis as soon as possible so the treatment can start.

Can my dog infect me?

Another important question dog owners want to know the answer to is - “Can my dog infect me?” Luckily, the answer is - NO. When the fungus enters a host, in this case, a dog, it enters a different life stage. That means it stops producing infectious spores, which means it is not contagious to humans or other animals. The worst thing an owner can do is abandon their dog because they fear an infection that simply cannot happen. At that time, your dog needs your support, and since owners are safe from the infection, providing it shouldn’t be a problem.

World Dog Finder team

World Dog Finder Logo