Pythiosis (Phycomyosis or Swamp Fever) in Dogs

Overview of Canine Pythiosis (Phycomyosis or Swamp Fever)

Pythiosis, also known as Swamp Fever and Phycomycosis, is an infectious disease in dogs affecting primarily the gastrointestinal tract or skin. The causative organism is Pythium insidiosum, a fungus that is in a class similar to yellow-green algae.

Pythiosis is seen more commonly in dogs than cats. Large-breed dogs, especially those used in hunting or field trial work near water are at higher risk. Labrador retrievers are most commonly affected with the gastrointestinal form, and German shepherds, the cutaneous (skin) form. Young to middle-aged male dogs are most commonly affected. Those exposed to warm freshwater lakes, swamps and ponds are most commonly affected. Most infections occur in the early spring, fall and winter months.

It is most common in warm humid parts of the country such as the Gulf Coast and Southern United States.

Transmission is by contact with infected spores that penetrate damaged skin or tissue. The organisms grow causing severe tissue damage that may include draining wounds that won’t heal and ulcerations. Thickening of the gastrointestinal tissue may be severe and cause complete obstruction.

What to Watch For

Signs of pythiosis (phycomyosis or swamp fever) in dog may include:

Diagnosis of Pythiosis in Dogs

Treatment for Pythiosis in Dogs

Prognosis for Pythiosis in Dogs

Only 1 out of 5 patients respond to medical therapy alone. Prognosis is fair if lesions can be surgically removed. Prognosis is poor if medical therapy is used alone or lesions are not surgically removable.

Home Care and Prevention for Pythiosis

Administer all medication and diet as directed by your veterinarian. If any change is noted in your pet’s condition, notify your veterinarian.

Unless the lesions are resectable or removable, the prognosis for long-term survival is poor. Minimize environmental exposure; keep your pet indoors if you live near warm, swampy bodies of water.