"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift

May 19, 2010

May 19 - Pythium insidiosum

Oh man - this is a nasty one. I had a really hard time finding a photo that wasn't completely disgusting and opted for just a nice image of the simple fungi themselves. The parasite is Pythium insidiosum, a fungal parasite that causes a disease known as pythiosis in dogs and horses. It's a common parasite in warmer parts of the world including the American South, eastern Australia, and south America and primarily exists in swampy, standing water. Dogs can become infected in their GI tract from drinking tainted water and it can cause thickening of the tissues or granulated lumps. Horses more often have subcutaneous lesions of these fungi, which they get from standing in the swampy water. The damage to their legs, bellies, and chests can be quite gruesome and often the lesions will have bits of dead tissue in them with the somewhat amusing name of "klunkers."

The disease is apparently on the rise in the U.S. and is troublesome because many vets are not familiar with it. I found this website with some rather sad tales of beloved pets who have been lost to the disease.

The image is from this site.


  1. We are researching this parasite because our three year old boxer was just diagnosed as having it. She has a large abdominal mass with the thickening of her intestines.Sickening weight loss(she looks so bad). We are trying to figure out how she got it(she is an indoor dog). Our other dogs(her parents) are fine. We are preparing ourselves for her passing. She is not a candidate for surgery due to it being so profusely throughout her digestive system.

  2. So sorry to hear that, Dawn! It does sound rather strange that your indoor pet got this. Please keep us posted if you find out anything more about how she might have picked it up - think it would be good for other dog owners and vets to be aware.