Deadly Waters: Blue-Green Algae
Updated: Jun 12
I remember wanting to cry when I saw the photos. Two adorable Westies and a Labradoodle in North Carolina went to the lake with their mom as a special summertime outing. In the wee hours of the following morning, their mom posted that all three “had crossed the rainbow bridge together.” My heart goes out to her every time I see an article about blue-green algae. I cannot imagine what she felt. She did, however, take her story to the media in an effort to prevent other pet parents from experiencing tragedy.
So many stories are similar to this one. A day that was supposed to be so special turned so wrong. We want to share some useful information about it since it’s becoming a more common danger. It is still fairly uncommon, and we don't want to create any unnecessary worry, but it is becoming more common, and we think it's important that everyone know about the dangers. It can be difficult to identify even if you do know about it, but we find that many of our clients have never even heard of it.
Read below to learn more about Blue-Green Algae--preventing your dog from getting into it in the first place is the key. To keep your dog safe, you should:
Learn About Blue-Green Algae
Understand Conditions it is Likely To Be Present and How To Identify It
Carry Fresh Water For Your Dogs; and
Seek Immediate Care If Your Dog is Exposed
First, What Exactly Is Blue-Green Algae?
Blue-green algae, also known as cyanobacteria, is a photosynthetic bacterium (nourishes itself from sunlight). It is a single-celled organism that may live in colonies, which occasionally can grow intensely, often referred to as a bloom. Due to many factors, including rising global temperatures and increased commercial farming, encounters with intense algae blooms, known as HABs (Harmful Algae Blooms) when they have they are toxic to humans or animals, appear to occur with increasing frequency. If you live in a coastal community or plan to visit, you may also want to read up on red tide (which may be one of several colors), a type of HAB associated primarily with salt water.
Where Is Blue-Green Algae Commonly Found?
Because of its increasing prevalence, however, we wanted to focus this article on blue-green algae. It is most commonly found it warm freshwater, such as ponds and lakes, especially in the summer However, it can also be found in brackish water, saltwater, and even in soil. One source mentioned that they may even be found in very small bodies of water, such as backyard ponds, wading pools, and even birdbaths. Even large bodies of water, such as Lake Erie, are not immune.
How To Identify Blue-Green Algae
Although the name might suggest this should be easy to spot, these blooms can vary in appearance, making them more difficult to accurately identify. Compare the photo above with the one at the top of the article, and consider searching online for other photos to see more examples.
Blooms may appear as hair-like strands or as floating mat, or even shoreline residue. They may form a thin scum on the water’s surface or look like a thick paint spill. Colors may range from green to blue to brown to reddish-purple. An odor may or may not be detectable. HABs may also be lurking on the lake bottom, near the shoreline, in swampy areas, soil, and sometimes even in moving water.
Are Blue-Green Algae Blooms Becoming More Common?
These HABs are, indeed, ubiquitous, having been noted in all 50 states and internationally. They thrive in warm, nutrient rich water, meaning that sunlight, warm temperatures, and the presence of nitrogen or phosphorus (often associated with runoff from fertilizers) contribute to the development of HABs. Climate change is undoubtedly a factor in their increasing prevalence. Manufacturing industries, including pulp and paper mills, and sewage treatment plants may also contribute.
Why Blue-Green Algae Blooms Are So Dangerous
Just how dangerous is cyanobacteria? The fact that the American Kennel Club (AKC), American Society for the Prevention of Cruelty to Animals (ASPCA), the Humane Society, the American Veterinary Medical Association (AVMA), and the Pet Poison Helpline all address it should be an indicator. The EPA and numerous research institutions also discuss its dangers. In researching this blog, I read two accounts of dogs and one of cattle that survived exposure to blue-green algae, and I was relieved to learn that not all exposures are fatal. An overwhelming majority of stories that receive media attention do not end as happily. The prognosis appears discouraging, both for pets and for people. Death can occur within minutes, hours, or days, and among survivors of any species, residual damage is a distinct possibility. At present, there is no known antidote to cyanobacterial poisoning.
Two major toxin groups are found within cyanobacterial blooms. The toxins are not so much a property of the toxins themselves as a product of metabolic and other life-sustaining properties of the bloom. Anatoxins, which are neurotoxins, pose the more immediate threats with such symptoms as drooling, tremors, muscle rigidity, blue coloration of skin and gums, and respiratory difficulties. Liver damage and possible failure are caused by microcystins. Related symptoms include pale mucous membranes, jaundice, blood or black coloration in feces, vomiting, disorientation, shock, seizure activity, and coma.
Therefore, the most important thing you can do is to know about HABs and prevent exposure. It is frightening how toxic this substance can be even in small doses and/or from indirect exposure—if your dog consumes smaller animals that may have died from cyanobacterial exposure, licks the fur of another pet that has been exposed, breathes in cyanobacteria, licks paws that have splashed in contaminated water, etc. And it can be dangerous to you if you're exposed to directly or by blowback from cleaning or hosing your pup off. Remember that dogs tend to drink when they swim, so they may be ingesting more toxins than a human would under the same circumstances, and it only takes a small amount to pose a major threat. There are veterinary treatments that have some success, such as oxygen, anti-convulsants, and surgical procedures, but please remember that the odds of a tragic outcome exceed those of recovery. If you even suspect that your dog may have been exposed to HAB toxicity, remember that every minute counts.
Remember, also, that even though you may be substantially larger than your dog, small amounts of cyanobacteria may be harmful or fatal to you. The Atlantic (September 18, 2012) provided the story of a man who was hosing off his dog in an effort to help him after exposure to blue-green algae. During the process, water splashed into the man’s left eye. Sadly, his beloved dog expired, and the man became ill from the exposure to his eye and was still experiencing complications two years later.
Hope for the Future
Some of the incidents described above led to requests for signage from the city, owners of private ponds, and/warnings on social media. However, there isn’t a systemic method for alerting health officials of potential threats. Many states have systems for reporting, but reporting is not currently mandated, and few people are aware of how or where to report incidents.
However, the JAMVA News has reported that as of 2016, the Centers for Disease Control (CDC) established a new subsidiary of the National Outbreak Reporting System, the One Health Harmful Algal Bloom System, which allows for the reporting of both human and animal cases of HAB-related illnesses. This process, in turn, will facilitate the examination of trends, community education, and a database that can provide important information to health professionals as they make diagnostic decisions.