Dangers of Blue-green Algae


Summer is a great time to get outside and enjoy nature, including the many beautiful lakes in our area. However, there’s a good reason to look at the water closely before jumping right in – it may contain a dangerous substance called blue-green algae. These algae are common in our area, and are extremely toxic to pets.    


What is blue-green algae? The Wisconsin DNR states that “blue-green algae, also known as Cyanobacteria, are a group of photosynthetic bacteria that many people refer to as "pond scum." Blue-green algae are most often blue-green in color, but can also be blue, green, reddish-purple, or brown. Blue-green algae generally grow in lakes, ponds, and slow-moving streams when the water is warm and enriched with nutrients like phosphorus or nitrogen. When environmental conditions are just right, blue-green algae can grow very quickly in number. Most species are buoyant and will float to the surface, where they form scum layers or floating mats. When this happens, we call this a "blue-green algae bloom." Blue-green algae blooms generally occur between mid-June and late September, although in rare instances, blooms have been observed in winter, even under the ice.”


Blue-green algae produce toxins that are harmful to people and pets. During certain times of the year, more toxins are released. However, it is impossible to know when the algae are producing the toxins without testing the water, so it’s safest to assume that any algae you see is toxic. The Pet Poison Helpline states that the toxins are extremely dangerous to pets - even very small exposures, such a few mouthfuls of algae-contaminated water, may result in fatal poisoning. The toxins can cause liver damage if ingested. Clinical signs of poisoning include vomiting, diarrhea, blood in stool or black, tarry stool, weakness, pale mucous membranes, jaundice, seizures, disorientation, coma, and shock. Death generally follows within days as a result of liver failure. Aggressive, immediate treatment is necessary to help treat this quick-acting, potentially fatal poison.  


Our veterinarians recommend checking water for surface algae before swimming and do not allow your dog to swim if you notice any signs of algae in the water. It’s also a good idea to monitor pets closely for any concerns after swimming, even if you did not see algae. Let us know right away if you see any of the concerns listed above.


Please call us if you have any questions or concerns. Together we can keep your pets safe and healthy so you can enjoy all that summer has to offer!    



Sources cited: Wisconsin DNR, Pet Poison Helpline

Photo credit: www.thepetwiki.com