Blastomycosis in Dogs: A Serious Fungal Infection Explained

Blastomycosis is a serious fungal infection that affects dogs and can also infect people. Caused by the fungus Blastomyces dermatitidis, it thrives in moist, damp environments rich in organic debris, such as near rivers, lakes, marshes and ponds. Though relatively uncommon in the UK, cases appear annually in veterinary clinics, particularly in dogs spending time outdoors in such habitats.

This article explores blastomycosis in dogs, highlighting how the disease is caught, its symptoms, treatment options, and tips for prevention and responsible ownership.

How Do Dogs Catch Blastomycosis?

Dogs develop blastomycosis when they inhale spores of Blastomyces dermatitidis from contaminated environments. The fungus lives in wet soil, decomposing leaves, rotting wood, and other organic matter commonly found in damp areas where water meets land, such as riverbanks, marshlands, and muddy ponds.

Working dogs like gun dogs, including the springer spaniel, are at a heightened risk due to their exposure to such environments during hunting and retrieving activities. Dogs who frequently visit similar areas for walks also face some risk, as fungal spores become airborne when the ground is disturbed.

Once inhaled, the spores lodge in the lungs where they multiply, eventually spreading via the bloodstream to other organs including the eyes, bones, skin and lymph nodes. Despite exposure being possible in many locations, not all dogs develop the illness; susceptibility varies with individual health and immune response.

Recognising Symptoms of Blastomycosis in Dogs

Spotting early signs of blastomycosis is vital because timely diagnosis significantly improves treatment success. Symptoms often develop gradually rather than suddenly and can affect multiple body systems.

Common signs include:

• Unexplained lameness affecting one or more legs
• Reduced appetite and weight loss
• Low-grade fever
• Persistent, sometimes painful, harsh cough
• Skin sores or lesions
• Eye lesions potentially affecting vision

If your dog regularly visits damp or watery environments and shows these signs, particularly coughing or sores, seeking veterinary advice promptly is crucial.

Treatment Options for Canine Blastomycosis

Left untreated, blastomycosis can become fatal. However, with prompt veterinary care, many dogs recover fully. The mainstay of treatment involves antifungal medications, typically itraconazole, administered orally for a minimum of three months but often extending to six months or longer depending on disease severity.

In severe or life-threatening cases, especially with respiratory distress or systemic spread, vets may recommend amphotericin B in combination with itraconazole. Due to inflammatory reactions caused by dying fungal cells, short-term steroid therapy might also be used to reduce lung inflammation.

Supportive care addressing secondary infections or symptoms is often needed during treatment. Regular monitoring through clinical assessments and urine antigen tests helps guide therapy duration and ensures infection clearance.

Preventing Blastomycosis: Responsible Care and Precautions

While preventing environmental exposure to the fungus entirely may not always be possible, responsible pet ownership can reduce risks. Avoid letting dogs swim or spend prolonged time in stagnant water areas prone to fungal growth, especially if they are working breeds or known to be vulnerable.

Maintaining strong general health through proper diet, exercise, and regular vet check-ups supports a robust immune system better able to resist infections.

What Is the Prognosis for Dogs Diagnosed with Blastomycosis?

The outlook depends on infection severity and timely treatment. Dogs with mild lung involvement generally have a good prognosis with appropriate antifungal therapy. However, prognosis worsens if the disease spreads to critical organs such as the brain or central nervous system or if diagnosed late.

Relapse can occur in around 20% of cases but many affected dogs respond well to retreatment. Continuous veterinary monitoring post-treatment is essential for early detection of any recurrence.

Summary and Next Steps

Blastomycosis is a serious fungal infection affecting dogs exposed to damp, organic-rich environments where Blastomyces dermatitidis thrives. Understanding how dogs contract the infection, recognising symptoms early, and accessing prompt veterinary treatment greatly improve outcomes. Responsible environmental management and good overall health can assist in prevention.

If you suspect your dog may have blastomycosis or if you frequently exercise your dog in at-risk areas, consult your vet promptly. Early diagnosis and long-term antifungal treatment are key to recovery.

Remember, sourcing your dog from reputable breeders and maintaining regular health checks supports your dog’s lifelong well-being. For more information on finding a springer spaniel puppy or other breeds, visit trusted UK breeders and pet adoption sites.