In July, I noticed a large lesion on the underside of Darwin's tail and immediately took him to the vet. Even though he started taking antibiotics, the lesion kept growing. It was heartbreaking watching it get worse, not knowing what it was. I diligently searched for an answer, and came across a disease called pythiosis.
Even though it's a rare disease, I also read it infects large breed young dogs with exposure to freshwater, and German shepherds are more susceptible. The next day I took Darwin to the University of Florida Veterinary School, and two days later I was told he had tested positive.
The organism that causes pythiosis isn't a bacteria, fungus or virus - it's from a family called oomycetes. It's a common cause of some of the most feared plant diseases, but this one species is known to infect horses, dogs and, very rarely, people. Dogs become infected by swimming in or drinking standing freshwater ponds or lakes, with most U.S. infections occurring in the Southeast.