What is Pythiosis in Dogs?

Did you know standing water is a breeding ground for a fungal infection that’s dangerous to canines?

Water and dogs seem to go together. While most bodies of water are safe for your dog to swim and splash in, standing water can be a water hazard. Standing water can be at risk for a serious fungal infection called pythiosis that, if left untreated, can become fatal. Protect your dog against this dangerous infection—learn the basics about pythiosis in dogs and how your canine might come in contact with it.

What is Pythiosis?

A fungal infection that can affect both dogs and cats, pythiosis is caused by a type of aquatic mold called Pythium insidiosum, which is found in stagnant water. This parasite is most commonly found in swampy areas in the southeastern United States, though it has been identified as far west as the central valley in California. It’s unlikely that your dog will contract pythiosis by swimming in a pool, stream, or river, but steer clear of standing bodies of water—they’re a breeding ground for this type of fungus. In most cases, mold spores enter the dog’s body through the nose or esophagus, although it can also enter through open wounds. Once inside a dog’s body, spores settle in the lungs, brain, sinuses, skin, or gastrointestinal tract where it develops into palpable masses.

Symptoms of Pythiosis

The gastrointestinal form of pythiosis is the most common pet owners will encounter. Symptoms include diarrhea, vomiting, and weight loss. Infected dogs can also develop palpable stomach masses. Less common is the subcutaneous form of the disease, which develops under the skin. Symptoms of this form of pythiosis include lesions on the head and legs as well as the area at the base of the tail. Often mistaken for granulomas or other skin growths, lesions can become itchy. If left untreated, these lesions can lead to skin and tissue death (necrosis).

dog swamp

istockphoto/ajansen

Treatment Options

To diagnose pythiosis, your veterinarian will do a complete physical exam. Tell your vet about all of your dog’s symptoms and be as specific as you can about when they first started. As well, your vet will likely perform several laboratory tests including a complete blood count (CBC), a chemical blood profile, an electrolyte panel, and a urinalysis.

Depending on the test results, your vet may recommend a radiograph and/or a biopsy of any physical masses. For treatment, surgery may be required to remove the affected tissues and laser treatment may be required afterward to kill any remaining fungal filaments. Even after surgery, dogs require medical treatment for six months afterward. As long as the disease is caught early and treatment is started right away, prognosis is generally good.

Pythiosis can turn into a serious condition if not treated soon enough. You should always be careful when letting your dog swim or play in bodies of stagnant water. If your dog develops any symptoms which could be related to pythiosis, take him to the vet immediately.

Meet the Author: Amy Tokic

Amy Tokic is the Editor of Petguide.com, the flagship site to over 70 different pet communities, which offers pet parents a one-stop-info-shop for all things dog and cat related. Amy's been with PetGuide since the beginning, guided by the wisdom of her Shih Tzu mix and furry roommate, Oscar. Together, this pet power couple has their paw on the pulse of the pet industry, sniffing out trends, advice, news, tasty treat recipes and other tail-wagging stories.

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