Few things look more summery than a dog splashing into a pond. Most of the time it is harmless fun. But in warm weather, some lakes, ponds and slow-moving rivers develop harmful algal blooms, and these can be extremely dangerous for dogs. Knowing the basics helps you make better choices about where your dog swims.
What blue-green algae actually is
The term blue-green algae usually refers to cyanobacteria, microscopic organisms that live naturally in fresh and brackish water. When conditions are right, often warm water, sunlight, calm conditions and plenty of nutrients from runoff, they can multiply rapidly into blooms. Some cyanobacteria produce toxins that can affect the liver, the nervous system or the skin.
Dogs are more likely than people to swallow water while swimming or fetching, and they often drink from lakes and ponds. They also lick their coats afterward, swallowing anything clinging to their fur. Toxins from some blooms act quickly. Illness can begin within minutes to hours of exposure, and severe cases can be fatal.
You cannot tell by looking
Blooms can look like green or blue-green scum, spilled paint, foam or mats on the surface, and the water may smell bad. But not every bloom produces toxins, and toxins can still be present when the water looks fairly clear. The safest approach is to be cautious:
- Keep your dog out of water that looks discolored, scummy or has floating mats.
- Avoid areas where algae has washed up along the shore, since dried mats can still be toxic.
- Check local and state environmental or health agency websites for bloom advisories before you go.
- Obey posted signs at lakes and parks.
- Bring fresh water so your dog is not tempted to drink from the lake.
Signs of possible poisoning
Symptoms vary depending on the type of toxin, but they can include vomiting, diarrhea, drooling, weakness, stumbling, trembling, difficulty breathing, seizures or collapse. Some dogs show signs of liver trouble, such as lethargy and loss of appetite, a bit later. Any of these after a swim in natural water is a reason to act immediately.
What to do after exposure
If you think your dog has been in or near a bloom, rinse it thoroughly with clean fresh water, wearing gloves if you can, so it does not lick off more toxin. Then call your veterinarian or an emergency clinic right away, even if your dog seems fine. Tell them where your dog swam and when. There is no home remedy for these toxins, and fast veterinary care gives the best chance of a good outcome.
Enjoy the water with a plan
Many lakes and ponds are safe much of the time, and a little advance checking lets you enjoy them with confidence. Pick spots with good water quality reports, stay alert for changes in how the water looks, and keep a fresh-water rinse in the car. When in doubt, choose a different spot or a hose and a kiddie pool in the backyard instead.
