You may see signs in the late summer and early fall warning you to keep out of ponds and lakes. This is because of the potential for exposure to blue-green algae. These algae produce toxins (microcystins and anatoxins) that can affect your dog’s nervous system and cause liver failure.
Prevention is easy. Just keep your pet out of standing water like ponds and lakes, particularly those bodies of water that have a greenish or brackish hue. However, clear water does not mean the water is safe to swim in or ingest.
The symptoms vary with which kind of toxin your dog has been exposed to. (You will not know which toxin is a more likely suspect until your dog exhibits signs of distress, so please refer to the paragraph on prevention.) Vomiting, diarrhea, seizures, yellow skin, excessive salivation and tear production, seizures, muscle tremors, difficulty breathing, and possibly death are all symptoms of exposure to a blue-green algae bloom. Humans can be affected by swimming or consuming contaminated water as well, although seemingly not to the extent that dogs are.
There is no antidote for exposure to blue-green algae toxins. Supportive care is the only treatment your veterinarian can offer you. Prognosis in these cases is guarded and depends on how much water the dog drank and the concentration of the toxins in the water at the time of exposure.
If you suspect your dog has been exposed to blue-green algae, a trip to the veterinarian is in your dog’s best interest.