Keeping Pets and Livestock Safe from Harmful Algal Blooms

Cyanobacteria, also called blue-green algae, are microscopic organisms found naturally in all kinds of water. Sometimes they multiply out of control in a bloom, and some blooms produce toxins (poisons) that sicken people and animals. Blooms are most common in fresh water such as lakes, rivers and streams. They can change the water's color or look like foam, scum, mats or paint on the surface.

For pets and livestock, the danger is serious: animals can become very sick and die within hours to days of swallowing cyanobacterial toxins, which can be in the cyanobacteria themselves or in the water.

Keeping animals away

If you think a body of water has a cyanobacterial bloom, do not let your pets or livestock:

• drink the water
• swim or play in it
• eat near it
• eat dead animals, such as fish, washed up on shore
• eat algae
• lick their fur after being in the water

The simplest rule: keep animals away from water that looks or smells bad.

If an animal goes in the water

Wash it off with clean water right away, so it cannot lick cyanobacteria off its fur. Call a veterinarian if the animal shows any of these signs:

• loss of energy or appetite
• vomiting or diarrhea
• stumbling or falling
• foaming at the mouth or excessive drooling
• tremors, seizures or convulsions
• any unexplained illness within a day or so of contact with the water

Where to get help

• Poison control: call your local poison control center at 1-800-222-1222 with questions about cyanobacterial toxin poisoning.
• Animal poison lines: the ASPCA Animal Poison Control Center (1-888-426-4435) or the Pet Poison Helpline (1-855-764-7661) can answer questions about pets or livestock; these calls carry a fee.
• Report blooms or illnesses to your health department, online or by phone.

Sources

• Centers for Disease Control and Prevention, "Preventing Pet and Livestock Illnesses Caused by Harmful Algal Blooms." https://www.cdc.gov/harmful-algal-blooms/prevention/preventing-pet-and-livestock-illnesses.html
• CDC, "How to Recognize a Harmful Algal Bloom": https://www.cdc.gov/harmful-algal-blooms/about/how-to-recognize-a-harmful-algal-bloom.html; animal safety fact sheet: https://www.cdc.gov/harmful-algal-blooms/media/pdfs/algal_bloom_tall_card.pdf