Canine Schistosomiasis

Canine Schistosomiasis

Does your dog play in the ponds and canals in our area? If so, you may want to re-consider….

In the past month, one of our patients came in with bloody, watery stool, vomiting, pain and lethargy. After several days of treatment and medications she was not improving and was transferred to the Internal Medicine Department at The Gulf Coast Veterinary Specialists. Following more aggressive diagnostics and treatments, they discovered that she had “Canine Schistosomiasis”.

What is Canine Schistosomiasis? It’s actually a disease caused by a parasite that lives in stagnant freshwater and can enter a dog’s bloodstream through their feet/pads. Most people have never even heard of this parasite. It can be a deadly parasite and difficult to diagnose and treat, but it isn’t all that uncommon- especially in the Southern regions of Texas. Here is an open-letter from our client regarding her recent experience with this parasite:

A warning to dog owners along the Gulf Coast (and southeastern US):

We had the unfortunate experience of learning all about a parasite that is endemic to the Gulf Coast, particularly Texas and Louisiana. It is called Heterobilharzia americana. Dogs are at risk if they swim/wade in water that contains a certain type of freshwater snail. The parasite penetrates the dog’s skin or mucous membranes and gets into the bloodstream. It then migrates to the liver then moves to the intestine. In the intestine, it invades the blood vessels and intestinal tissue causing a significant amount of inflammation. Eggs are passed in the feces. If the eggs contact freshwater, a form of the parasite is released that can penetrate a snail’s soft tissue. The parasite reproduces inside the snail and free-swimming forms of the parasite are released and the sequence starts over again.

Life cycle of Heterobiharzia americana
Some interesting tidbits we learned:
  • Infected dogs have bloody vomiting and diarrhea, weight loss, lethargy, and significant debility.
  • Often there is a significant delay in diagnosis because symptoms are usually attributed to other things. Too much of a delay can be deadly.
  • People will not be in infected with this parasite. However, humans exposed to the contaminated water may have “swimmers itch” because of skin penetration from the parasite. Once inside a human, the parasite is unable to complete its life cycle.
  • Raccoons are the natural definitive host, but apparently dogs and some other mammals work too. The snail and freshwater are required for transmission. There is no direct transmission between dogs, or between dogs and raccoons.
  • It takes about 10 weeks from the time of initial skin penetration to when eggs are shed in the dog’s feces.
  • Most cases are in Texas and Louisiana, but cases have been diagnosed in dogs throughout most of the southeastern US and as far north as Kansas.
  • Samples are sent to Texas A&M for diagnosis.
  • Treatment is not always effective, but a high dose of a combination of antiparasitic medications can result in resolution of the clinical signs in some dogs.
  • The recommendation for prevention is to not allow your dog to swim in canals or ponds.

Ripley had significant intestinal bleeding, intractable vomiting, was weak, miserable and in a significant amount of pain. She needed to be carried into the car because she was too weak to walk. Thanks to the wonderful people at Gulf Coast Veterinary Specialists, she was able to come home after only three days in the Doggy ICU. She is doing much better now but is not 100% yet. She still has a long road ahead. She is just starting her treatment, which at such high doses has unpleasant side effects. Thankfully only two days now, then another two days in a month. Fingers crossed that it will be effective.

“Thanks to the wonderful people at Gulf Coast Veterinary Specialists, she was able to come home after only three days in the Doggy ICU. She is doing much better now but is not 100% yet. She still has a long road ahead.”

Of note to the people in this area, the only real pond she has splashed around in is the retention ponds (Sunrise Lake) in The Reserve. I do not know for certain but am concerned that this water may be contaminated. I would hate for other dogs to go through what ours has.

Interestingly enough, our client shared this post on Next Door and a neighbor responded detailing their recent experience with this parasite. Their dog contracted the parasite from stagnant water towards the back of Sylvan Rodriguez Park and almost died during treatment. They too were completely unaware of the parasite and the risk of exposure by allowing their pup to play in the water at the park.  

Prevention is key! Avoid allowing your dogs to play in stagnant bodies of freshwater in the area. Be sure to tell your vet if your dog has been playing in stagnant bodies of water- especially if they have had any sort of gi issues.

Thankfully, Ripley is finally starting to feel like her happy, sweet self again!

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