Recent news reports have shed light on a little-known pet danger: blue green algae. Several dogs have died recently after swimming in contaminated water, some as quickly as minutes after exposure. If your pet has access to water, or you plan on taking your pooch for a swim, here’s what you need to know to keep him safe.

What is blue green algae?

Blue green algae are microscopic cyanobacteria that can grow in all water types, from ponds and lakes to rivers and streams, across the U.S. They are found in both fresh and marine water, and even grow in inadequately treated swimming pools. Although algae are present in many bodies of water, their numbers fluctuate throughout the year, and populations rarely reach dangerous levels. During the late summer, however, hot weather can cause harmful algal blooms that are characterized by rapid cyanobacteria growth and toxin production that can be harmful to pets and people. Most blue green algae does not produce toxins, but there is no easy way to differentiate toxic algae from harmless varieties. 

Blue green algae typically discolor the water, making it appear blue, bright green, brown, or red. They often float on the surface and can look like foam, scum, or paint covering the water. Algal blooms can be blown into thick mats near the shore or on the banks of lakes and rivers, where pets and livestock can be exposed without actually going into the water. Blue green algae sometimes produce a nauseating smell, but lack of an odor does not mean the algae is safe. 

How can my pet be exposed to blue green algae?

Most blue green algae exposures occur when pets swim in or drink water that contains toxic algae. Unsuspecting owners may allow their dog to swim in a pond or lake containing the bacteria, or a roaming dog may drink from or swim in a nearby body of water. Hunting dogs and pets who spend a lot of time near the water are at higher risk of being exposed than pets who spend most of their time within the boundaries of their owners’ yards. Pets can also eat algal mats that are pushed onto the shore and dry out, or may groom the algae off their fur.  

How can blue green algae affect my pet?

Blue green algae toxicity is a serious threat to all animals and can quickly cause severe illness or death. Toxicity signs can appear from minutes to days after exposure, and can include: 

  • Vomiting
  • Diarrhea, which may contain blood 
  • Tarry stool
  • Drooling
  • Pale, blue, or yellow mucous membranes
  • Disorientation 
  • Seizures
  • Coma
  • Shock
  • Incoordination
  • Muscle tremors or rigidity
  • Difficulty breathing
  • Sudden death

Blue green algae can produce two different toxin types that affect pets differently. Microcystins cause liver failure that can progress to death within days of exposure. Anatoxins cause a more acute onset of neurotoxicity that results in respiratory paralysis and death within minutes to hours. Animals exposed to anatoxins are often found dead near a water source after drinking, since toxicity advances so quickly.  

If you think your pet may have been exposed to blue green algae, seek veterinary medical care immediately, as toxicity can progress rapidly and aggressive treatment is critical to survival.  

How can I keep my pet safe from blue green algae?

Blue green algae toxicity poses a life-threatening risk to your pet, and you should avoid contact with potentially contaminated water. Several lakes in the eastern coastal states have been closed in the past several weeks after pets became ill or died following accidental blue green algae exposure. Allowing your pet to take a dip in the local swimming hole is a fun way to beat the summer heat, but take care to avoid exposing him to toxic blue green algae by following these tips:

  • Never allow your pet to go near discolored water, especially if it is blue, green, red, or brown.
  • Never allow your pet to go near water that has a bad odor.
  • Stay away from water that looks like it has a layer of scum, foam, slime, paint, or algae on the surface.
  • Don’t allow your dog to eat dried algae near bodies of water.
  • Heed signs warning people and pets to stay away from water affected by harmful algal blooms.

What should I do if my pet has been exposed to blue green algae?

If you suspect your pet has been exposed to blue green algae, thoroughly rinse him with plenty of fresh, clean water. Remember to wear gloves to avoid exposing yourself, since the toxin can also affect people. Watch your pet closely for toxicity signs, and if he is not acting like himself, bring him to our veterinary hospital immediately for evaluation. There is no antidote for blue green algae toxicity, and once clinical signs begin, they can quickly progress to death. Treatment must be started immediately for the best chance of survival.

If you have any questions about blue green algae toxicity, or if you think your pet may have been exposed, contact us.