Blue-Green Algae – A Potential Hazard for Horses, Pets and People

drinkingCurrent weather and water conditions in many parts of the country have created conditions favorable for the rapid growth of blue-green algae. Please be on alert with your horses and dogs, and use precaution when around unfamiliar water sources.

These primative organisms are actually algae-like bacteria instead of being true algae and are also referred to as Cyanobacteria.  They grow rapidly and may produce the pea-soup green color in some bodies of water, along with some foul odors.  These rapid growth periods, called “blooms” most frequently occur when there is a combination of warm weather, intermittent or limited rainfall and an accumulation of nutrients, particularly phosphorus and nitrogen.

The planktonic groups produce the pea green water while the mat-forming groups produce dark mats that start on the bottom and float to the surface.  The planktonic species (Anabena, Aphanizomenon and Microcystis) are believed to be most likely to produce toxins which can be harmful or fatal to animals when ingested. (Fact Sheet on Toxic Blue-Green Algae, Purdue University, Carole A. Lembi)

These toxins may be ingested when animals drink the water or when they lick their coats after being in the water.  Animals are more likely to consume the water if fresh water supplies are limited from other sources.  Any animals that drink the water during a period when toxins are being produced may be affected, but toxins are not always produced when there is a bloom.

Providing a source of fresh, clean, safe drinking water is the best way to avoid causing animals to consume questionable water.  If pets go swimming, they should be cleaned off before they have a chance to lick their coats.

Toxic symptoms may include:

  • Vomiting
  • Diarrhea
  • Rash and skin irritation

Preventing run-off of nutrients into ponds and lakes is also important to help reduce the risk of these algae blooms.  Prolonged drought conditions in some areas have also increased the concentration of nutrients in the remaining water in ponds and lakes.

While not all “blooms” may produce toxins, avoiding exposure to or consumption of suspect water is recommended.  More information is available from local and state pollution control sites or extension sites.   A recent case in Minnesota reported that 2 pets had been killed and a boy was sent to the hospital (MPLS Star Tribune, July 4, 2015, Liz Sawyer) due to exposure to blue-green algae.

2 Replies to “Blue-Green Algae – A Potential Hazard for Horses, Pets and People”

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