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DNR warns beachgoers of blue-green algae risks

Posted at 1:03 PM, Jul 17, 2021
and last updated 2021-07-17 14:03:44-04

WISCONSIN — The Wisconsin Department of Natural Resources is warning the public about the risks associated with blue-green algae. It can be harmful for humans and pets.

Blue-green algae can cause illness if it is swallowed or inhaled in water droplets, and can also cause irritation if rubbed on the skin.

The algae are most often green, but can also be blue, tan, reddish-purple or brown. It usually grows in lakes, ponds and slow moving water. Blue-green algae increases in number when environmental conditions are just right.

The DNR recommends that you assess the conditions of the lake before swimming in it to stay safe.

They say:

For humans :

  • Do not swim in water that looks like "pea soup", green or blue paint, or that has a scum layer or puffy blobs floating on the surface.
  • Do not boat, water ski, etc., over such water (people can be exposed through inhalation)
  • Do not let children play with scum layers, even from shore.
  • Do not let pets or livestock swim in, or drink waters experiencing blue-green algae blooms.
  • Always take a shower after encountering any surface water (whether or not a blue-algae bloom appears to be present; surface waters may contain other species of potentially harmful bacteria and viruses).
  • Try to avoid swallowing lake water, no matter how clean it looks, since it may have bacteria, viruses, or parasites in it that could make you sick.

If dogs swallow a lot of water containing blue-green algae when they're producing toxins, they can become very ill and even die.

For pets:

  • Do not let pets swim in, or drink, waters experiencing blue-green algae blooms or noticeably green water
  • Keep dogs out of shallow, stagnant waters where blue-green algae may be growing on the bottom and dislodged by disturbance, If people shouldn't swim there, dogs shouldn't either.
  • Always offer fresh, clean water for pets to drink instead of lake water.
  • Always wash dogs off with clean water immediately after they swim, so they don't lick any algae from their fur.
  • Supervise pets when they are outside so they don't eat algal scum accumulated on the shore, floating mats of algae or drink lake water.
  • If a pet eats grass, avoid using lake water for lawn irrigation if blooms are present.
  • If there's any doubt about what is in the water, keeping pets out is the safest course of action.

Symptoms of water intoxication from swallowing too much water and heatstroke in dogs include vomiting, diarrhea, lethargy, and loss of coordination.

If you think you're experiencing symptoms related to exposure to the algae (stomach cramps, diarrhea, vomiting, headache, fever, muscle weakness, difficulty breathing), contact your doctor or the Wisconsin Poison Center (1-800-222-1222) right away. If your pet displays symptoms, contact your veterinarian right away.

If you see a significant algae bloom you're encouraged to report it to the DNR at, and include the location of the bloom, name of the water body, nearest town, county size and duration of the bloom and closeup photos for verification.

Click here for more information.

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