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Blooms of blue-green algae have been identified in lakes across Alberta and is a common occurrence during the summer months especially when the water temperature is warmer and there is a high nutrient content in the water. The sudden growth of the bacteria when the conditions are favorable is known as a “bloom” or “cyanobacteria bloom”. Blue-green algae can look like pond scum, fuzz, or globs on the water’s surface and can appear blue-green, greenish brown, brown, or pinkish red in colour with a musty or grassy smell. Blue-green algae is actually a bacterium called cyanobacteria which can produce toxins which are harmful to the liver and nervous systems and be irritating to the skin. All animals including dogs, cats, horses, livestock, fish, birds and humans are susceptible to the toxins produced by cyanobacteria. 

Bodies of water that contain blue-green algae should always be  avoided by you and your animals. Do not allow your animals to drink, swim or wade in contaminated water, and if contact is made by you or your animal wash the exposed areas immediately. Whole fish or fish trimmings from contaminated bodies of water should not be ingested by animals. It is also imperative that water contaminated with blue-green algae is not used to cook, drink, water vegetable gardens or moisten dry dog food and the toxin produced by cyanobacteria will not be destroyed by boiling the water. 

If you suspect your animals’ water may be contaminated, remove access and find them an alternate water source. If you use a dugout to supply water to livestock or horses, inspect it at regular intervals over the warmer months and if you suspect a cyanobacteria bloom, restrict access and find an alternate source of water. There are a number of things you can do to improve your dugout, such as building a deeper dugout with steeper walls will help to keep it cool and free from blue-green algae.

If you suspect your animal has been exposed to blue-green algae or has symptoms of blue-green algae toxicity, contact your veterinarian immediately. There is no antidote for blue-green algae toxicity, and treatment is symptomatic, therefore early treatment is very important.

Symptoms of blue-green algae toxicity can be variable depending on the toxin(s) produced but may include:

• Neurological – muscle rigidity, tremors, seizures, collapse, sudden death
• Liver toxicity – vomiting, diarrhea, pale or yellow gums, seizures
• Skin irritation – itchy, red, blistered skin

Exposures in livestock and horses are typically diagnosed after animals are found dead near contaminated water but if detected early the symptoms can include all the above. 

The disappearance of visible blue-green algae on the body of water does not indicate that the water is safe. The harmful toxins can remain in the water for several weeks after the algae blooms have disappeared. For more information on affected areas and the status of particular lakes, please visit Alberta Health Services.