Risks of Blue-Green Algae

by Tom Ward

Blue-green algae are photosynthetic bacteria known as cyanobacteria and are a natural part of water bodies in Wisconsin.  With enough sunlight and nutrients, cyanobacteria can grow to high levels and form a blue-green algae bloom.  Blooms are often smelly, look like spilled paint or pea soup, and can change the color of the water to green, blue, turquoise, purple, tan, or white. Some blooms form a layer of scum or mats on the surface of the water.

green scum on water

An outbreak of blue-green algae was reported in June on Long Lake near Brillion. Photo by June Scharenbroch.

Blue-green algae blooms can produce toxins, called cyanotoxins. Cyanotoxins can make people and animals sick after they swallow, breathe in, or have contact with the water. Many dogs have become sick and some have even died after swallowing water containing cyanotoxins.

Pets are especially susceptible to blue-green algae because they don’t naturally avoid smelly, green water. Because of their relatively small size, animals do not need to ingest very much tainted water to become ill. When dogs swim and play in water, they tend to swallow water and they can get sick after swallowing just a little bit of unsafe water. Many dogs have gotten sick and some have died as a result of drinking water experiencing an algal bloom or by licking their fur after swimming in algae-filled waters.

If you think you are experiencing symptoms related to exposure to blue-green algae (e.g., stomach cramps, diarrhea, vomiting, headache, fever, muscle weakness, difficulty breathing), contact your doctor or the Wisconsin Poison Center (800-222-1222) right away.

If your pet displays symptoms such as seizures, vomiting, or diarrhea after contact with surface water, contact your veterinarian right away.

To report an algae bloom sighting email DNRHABS@wisconsin.gov. Include the bloom size, duration, and location with water body name, town name, and county name. Please submit photos for verification including close-ups and overall views. There is a link to an online reporting tool on this page at the Department of Health Services: https://www.dhs.wisconsin.gov/water/bg-algae/index.htm

Most local health departments in Wisconsin and Manitowoc County do not have the capacity to monitor blue-green algae toxins at public beaches, so treat any accumulation of blue-green algae with caution.

When in doubt, stay out!

Source: https://www.dhs.wisconsin.gov/publications/p01888.pdf


Updated: October 22, 2020 — 5:24 pm

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