Understanding Blue-Green Algae
The term “blue-green algae” generally refers to a toxic type of bacteria called cyanobacteria that lives in algae. Scientists call a rapid increase in algae growth a bloom. When blooms occur, cyanobacteria numbers increase. An algal bloom may turn the water pea-green or form a thick mat of green or blue-green algae on the surface.
Algal blooms occur most commonly in freshwater sources, including lakes and ponds. They also occur in brackish water, where a river meets the sea. This water is saltier than fresh water but not as salty as the ocean. Algal blooms are more likely during warmer months, when nutrient levels increase, in stagnant water, or during low rainfall. However, blue-green algae occur worldwide and remain present year-round. It’s safest to assume that any algal bloom could be toxic to both dogs and people.
Wind can blow an algal bloom to one side of a body of water or push it toward the shore. Officials may post warning signs near bodies of water with confirmed toxic cyanobacteria. Most blue-green algal blooms do not produce toxins, but a small amount produce very harmful toxins that can cause life-threatening symptoms or death. Harmful blue-green algae can cause severe clinical signs in dogs and are also toxic to humans.
Unfortunately, it is impossible to tell with the naked eye if an algal bloom is harmful. Therefore, it’s safest to assume that any algal bloom could be toxic to both dogs and people.
What Is Blue-Green Algae Poisoning in Dogs?
Treat any exposure to blue-green algae, whether large or small, as toxic. When a dog drinks or swims in water with toxic blue-green algae, the various toxins produced can affect a dog’s liver, neurologic system, or skin. If the toxin affects the liver, it can cause liver failure within a few hours. If the toxin affects the neurologic system, your dog can develop signs of abnormalities within an hour. Skin signs usually develop more slowly and may appear several days later.
The toxins affecting the liver and neurologic system are typically fatal, causing death within minutes to hours or a few days. Dogs exposed to the toxin that affects only the skin usually survive but still need treatment.
Are All Blue-Green Algae Toxic?
Not all blue-green algae are toxic. Approximately 2,000 species of blue-green algae exist, and scientists consider only about forty toxic. Although most algae blooms do not produce toxins, it is impossible to specifically identify toxic blue-green algae visually. Therefore, it is important to be wary of all visible algal blooms.
Symptoms of Blue-Green Algae Poisoning in Dogs
Depending on the toxins present, blue-green algae can affect a dog’s liver, neurologic system, or skin. Clinical signs may include vomiting, diarrhea, drooling, reddening of the skin, blisters on the skin, muscle tremors, muscle rigidity, seizures, inability to walk, difficulty breathing, weakness, and death. Because signs can develop rapidly and become life-threatening, seek veterinary care immediately after exposure.
How Do Veterinarians Treat Blue-Green Algae Poisoning in Dogs?
The goals of treatment are to prevent further exposure to and absorption of the toxin, control life-threatening symptoms, and provide supportive care. If your dog is not showing signs after known exposure, the vet may induce vomiting and give your dog a bath. Due to the risk of vomit entering the lungs, never try to induce vomiting at home.
Dogs that ingest toxic blue-green algae may need aggressive and intensive care, including medications to control tremors and seizures, fluid support, close monitoring of blood work, medications to support the liver, and potentially placement on a ventilator to help them breathe. The best way dog owners can keep their dogs safe is by keeping them away from water with visible algal blooms.
Unfortunately, because clinical signs of some types of blue-green algae poisoning develop quickly and exposure is usually fatal, treatment tends to be unsuccessful. If your dog only develops clinical signs that affect their skin, they can survive. In this case, they may need topical ointments, topical antibiotics, or oral antibiotics to treat their blisters.
Can a Dog Survive Blue-Green Algae Poisoning?
Different species of blue-green algae produce toxins that cause different clinical signs. Exposure to the toxins that damage the liver or cause neurologic signs typically results in death. If your dog is exposed to the toxin that only affects the skin, they typically survive but still require treatment at a veterinary clinic.
Prevention of Blue-Green Algae Poisoning in Dogs
The best way dog owners can keep their dogs safe is by keeping them away from water with visible algal blooms. Algal blooms can occur in freshwater, such as ponds and lakes, and in brackish water, such as where a river meets an ocean. If you are with your dog in any of these areas, look for visible algal blooms or warning signs indicating a harmful bloom is present. Algal blooms occur more commonly during warmer temperatures, so exposure is more common during summer. However, researchers have detected the toxins year-round.
Keeping your dog in a harness when near an open body of water will allow you to gently pull them back from any suspicious plant material. Because algal blooms can be so devastating, if you see an algal bloom, it is best to keep your dog away and report it to the environmental health section of your local health department.
. . .
This article is intended solely as general guidance and does not constitute health or other professional advice. Individual situations vary and you are encouraged to obtain appropriate advice from qualified professionals.
