What is Swamp Fever in Dogs?

Our question this week was:

Hi Dr. Debra – I looked on your site for swamp fever but couldn't find it. Do you know what it is?


Sally J. – Tulsa, OK


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

It is most common in large breed dogs that swim in freshwater lakes, swamps and ponds in the Gulf Coast and Southern United States regions.

It is a severe disease that can either cause severe skin wounds or gastrointestinal problems.

An article that might be helpful to you is Pythiosis (Phycomyosis or Swamp Fever).

Dr. Debra

P.S. You were right – we had the article but it was only called "Pythiosis" so we renamed it so it might be easier to find!

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