With summer winding down, it seems like everyone is trying to squeeze in one last summer vacation. And for many people, that involves heading up to that little lake somewhere “up north” and enjoying a relaxing time. This last big summer family vacation (often with our pets) most likely includes some well-deserved time in the water, swimming and enjoying the warm weather. 
While that does sound amazing right now, it also could mean increased danger for both you and your pet. During mid to late summer, it is common to see large amounts of algae blooming on many smaller inland lakes, ponds, or streams. Besides looking gross, these algae can also be toxic for people and pets.
What is blue-green algae?
You may have seen recent news stories about pets becoming ill or dying from toxic blue-green algae. Problems with this algae are not a new. Blue-green algae (cyanobacteria) is often found in bodies of fresh water during the warm-weather months. The algae flourishes during the warm and sunny times, allowing the bacteria to produce toxins. These toxins, if ingested, can then be extremely dangerous or even deadly to humans, dogs, cats, livestock, birds, and fish. Now, it is important to remember that not all blue-green algae blooms will produce these potentially life-threatening toxins. However, since there is no way to tell which blooms are toxic without testing them, it is best to assume all blooms are dangerous.
How to spot blue-green algae?
Water that is affected by blue-green algae will often have a distinct pea-green appearance to the surface of the water, almost as if someone dumped a bucket of green paint into the water. It may also appear like a green, slimy substance on the top of the water. For some lakes and streams, algae may cover the entire surface of the water, while for others you may need to look a little closer to the shoreline or river banks. Sometimes the blue-algae is present in lower amounts and can only be seen at the shoreline as it washes in, and will look like green and slimy.
How will blue-green algae affect my pet?
Signs of potential algae poisoning can range from severe liver damage to severe neurotoxicity depending on the toxin in the algae. Some of the most common signs of toxicity include:
- Vomiting or diarrhea
- Bloody or tar-like appearance to the stool
- Weakness
- Excessive drooling
- Panting
- Seizures
- Disorientation
- Muscle tremors
- Paralysis
- Difficulty breathing
- Discoloration of gum or skin color (typically either yellowing or a blue discoloration)
Please keep in mind not all pets that have blue-green algae poisoning will show all of the same symptoms or signs.
What if my dog has been in or has drunk some affected water?
Since poisoning typically occurs after ingesting (eating or drinking) the algae-contaminated water, toxicity signs are not typically seen from a pet just stepping into the algae. Please keep in mind though that many pets will then try to lick themselves clean and can become effected.
If your pet managed to quickly dip a toe in before you noticed the algae, quickly wash the area thoroughly to reduce the risk of exposure. That slimy algae can be very difficult to completely clean off your pet!
If your pet has drunk from water affected from blue-green algae, get veterinary care as soon as possible. Please realize that even a few small sips of this water could produce significant problems for your pet. Unfortunately there is no cure for the toxins that the algae can produce, and in some cases (depending on your pet’s exposure) the toxins can be fatal within minutes to hours of exposure.
Prevention is the key!
Check the water before you or your pets go in. Make sure that you look at the water as well as the shoreline or riverbank to look for signs of algae or green slime. If it’s there…don’t go in the water and keep your pets safely away.
Don’t let your pets drink form stagnant water as it is more likely to be affected by algae. Always wash your pet well after swimming. Stay informed! Many public health departments will post signs if there is a known problem with a specific lake or area. Listen to their warnings and avoid those areas. With some careful precautions, you can still enjoy these final few days of summer!
Dr. Heintz is a small and exotic animal veterinarian at 