Blue Green Algae and Dogs: Symptoms, Prevention

Blue green algae and dogs create a potentially deadly combination, and this very real hazard often catches dog parents unaware. Integrative veterinarian Dr. Julie Buzby is here to spread the word and arm you with information about blue green algae toxicity in dogs. Get the facts so you can safeguard your canine companion from this deadly toxin.

If you have a water-loving dog, make sure you are aware of the threat posed by blue green algae. Exposure to this cyanobacterium can have fatal consequences. Knowing what to watch out for can help keep your dog safe.

Blue green algae and dogs = Danger

I have heard two very tragic stories, one from a veterinary client and one from a fellow veterinarian. I share both accounts here, not to scare you, but to help spread the word about the tragic consequences of a toxin that doesn’t receive much media attention. It strikes lightning fast and has deadly consequences.

By sharing these stories, I hope to honor the memories of these dear dogs and help prevent future tragedies.

Recently, a fellow veterinarian received a distressed call from her parents saying that their 3-year-old Aussie was acting funny and might be having a seizure. Alarmed, the veterinarian jumped in the car and headed over to her parents’ farm, which was right next to hers. Sadly, when she got there, the dog had already died.

They soon made a second horrifying discovery—her parents’ other dog, a 10-year-old Aussie, was also dead. Everyone was devastated. Her parents’ formerly lively house was now silent and dogless.

The second story was shared by one of my veterinary clients. His young Golden Retriever had been frolicking in a nearby pond and quite suddenly died in the water. The dog’s tragic death happened within minutes. There was no practical treatment. There was nothing the dog parent could do.

The culprit in both of these cases? Blue green algae that produce toxins hazardous to humans and potentially fatal to dogs.

In the case of the first story of the two Aussies, an irrigation canal two properties over from them later tested positive for blue green algae and its toxins. The family thinks irrigation water must have pooled on top of a bucket, and the dogs both drank from it while outside going potty that morning.

To understand more about this toxin and to protect your dear dog, please read on.

What are cyanobacteria (blue green algae)?

While the name suggests that this toxin is an alga (i.e., a simple aquatic plant), blue green algae is actually a toxic microorganism called cyanobacteria. This poisonous microscopic bacterium is often found in stagnant water but can be found in any amount or type of water.

Toxic “blooms” have been described as looking like “paint” floating on top of the water. Outbreaks are most common in the summer months.

Why is blue green algae dangerous to dogs?

Sadly, toxins produced by blue green algae may be ingested as easily as a dog innocently lapping up a few sips of the water that’s essentially poisoned. In other instances, a dog may ingest the toxins simply by licking his or her fur after wading in contaminated water. When dogs drink or swim in water that has cyanobacteria in it, they can become sick within minutes.

There have also been reports of toxicity after well-meaning pet parents have given their dogs over-the-counter supplements containing blue green algae. Death for the dog can occur in 20 to 30 minutes.

What are the symptoms of blue green algae poisoning in dogs?

In dogs (and other animals), the toxins in blue green algae have a tendency to primarily damage both the liver (like many toxins) and the nervous system. Clinical signs of poisoning include:

• Muscle tremors
• Rigid muscles
• Seizures
• Vomiting
• Diarrhea
• Salivation
• Weakness
• Dilated pupils
• Respiratory failure (this may also cause pale or blue gums)
• Urinary incontinence
• Collapse
• Sudden death

In some tragic instances, dogs die suddenly without showing any other symptoms.

Where can blue green algae be found?

Also known as cyanobacteria or cyanobacterial blooms, blue green algae can be found in:

• Natural and man-made ponds
• Ponds set in landscaping in the yard
• Standing water
• Fresh water
• Lakes
• Brackish water
• Oceans
• Rivers
• Puddles
• Water troughs or buckets

How can I tell the difference between toxic blue green algae and generic pond scum?

Unfortunately, the answer to this question isn’t what you want to hear.
It is impossible to identify toxic cyanobacteria with the naked eye, as many types of algae can appear similar.

Determining whether algae are toxic requires an expert to identify toxic cyanobacteria in a water sample. A handful of veterinary diagnostic labs also have specific assays that can detect the presence of the toxins.

Additionally, the name “blue green algae” can be a bit misleading since cyanobacteria can be red or pink, in addition to the expected bluish green.

However, I believe it’s important to have a general idea of what blue green algae looks like, and I am a firm believer that a picture is worth a thousand words. There are several photos of toxic blue green algae throughout this article, including the picture below.

In addition to the water’s appearance, you can also look at other species in the water. If you see dead fish or other dead animals around or in the water, it may be due to toxic blue green algae.

Are all cyanobacterial algae blooms toxic to dogs?

Not all cyanobacteria are toxic. More than 2,700 species of cyanobacteria have been identified, though scientists estimate there likely are thousands more species. However, only about 50 of those species are toxic to vertebrates.

The toxins from cyanobacteria have harmed humans and animals for thousands of years.

Researchers estimate that 25 to 75% of cyanobacterial algae blooms are toxic. There’s no reason to take the chance. Keep your dogs (and children and yourself) away from bodies of water with algae and err on the side of caution.

Caution: Blue green algae and dogs just don’t mix!

When is blue green algae at its worst?

Blue green algae is both a regional problem and a seasonal problem. It’s at its worst during periods of hot weather when the water is warm, but growth can occur at cooler temperatures, too.

Lack of rain or an influx of nitrogen and phosphorus may also contribute to algae blooms. When blooms occur, this creates pockets of toxins that may move from place to place or eventually dissipate.

Often local authorities at lakes or parks recognize the risk and take appropriate precautions by closing lakes to the public during a bloom.

What should I do if I suspect blue green algae poisoning?

When to call your vet: Blue green algae is an emergency. If your dog may have been exposed to blue green algae, stop reading this and take your dog to the emergency vet right away!

If you suspect that your dog has come in contact with toxic blue green algae, seek veterinary care immediately at the nearest clinic. Even a few laps of water or wading in a few feet can be highly dangerous to dogs if the water contains the toxins.

Severe signs and death may occur within minutes to hours, so time is of the essence. Unfortunately, since this toxin works incredibly fast, some dogs may not even survive long enough to get to the vet.

If your dog has been exposed to blue green algae, toxins on your dog’s coat can cause skin irritation if you touch it. Wear gloves or wrap your dog in a towel, if possible, on your way to the vet to minimize your contact with the algae. Consult your physician if you are concerned that you may have had contact with toxic blue green algae.

How is blue green algae toxicity in dogs diagnosed?

There is no specific test to confirm blue green algae toxicity. Diagnosis is based on symptoms and history of exposure to a water source that may have algae in it. Blood tests can show changes in liver values if toxins are causing liver failure.

Unfortunately, without being able to run a specific test, blood test results can appear similar to other toxicities, such as chocolate toxicity in dogs or xylitol toxicity in dogs. It is essential to let your veterinarian know if your dog has had exposure to water that may have contained algae.

What is the treatment for blue green algae toxicity in dogs?

Unfortunately, there is no antidote for blue green algae toxicity. Your vet will do his or her best to manage your dog’s symptoms.
Treatments can include:

• Supportive care therapies
• GI protectants
• Liver protectants
• Fluid support
• Seizure control medications

Getting your dog veterinary care ASAP gives your dog the best chances of survival. But unfortunately, the overall prognosis is still guarded to poor. This is why prevention is the best medicine.

How can I protect my dog from blue green algae?

The only surefire way to protect your dog from cyanobacteria toxicity is to avoid exposure.

Many dogs enjoy swimming or wading in ponds and lakes, especially in the summer. Alternatively, when you are hiking, it may be natural for your dog to want to grab a sip of water from a pond or puddle. However, if the water has scum on it, run, don’t walk, the other way.

Since the only way to be 1000% sure the water doesn’t contain cyanobacterial toxins is to have it looked at by an expert or run a diagnostic assay, it’s better to avoid the situation altogether. You and your dog will be glad you did.

You can protect your dog from blue green algae in the following ways:

• If you have water on your property and your dog has free roam, keep a close eye on any areas where water collects, like water troughs, buckets, streams, and ponds, to ensure you don’t see signs of blue green algae. If you see anything suspicious, keep your dog out of that area.
• Keep water in troughs, water bowls, etc. clean and changed regularly.
• When walking or hiking with your pup, carry fresh water and a bowl for him or her and offer frequent water breaks.
• Check local sources for information on cyanobacteria in nearby waterways. Many regions and states have websites to report algal blooms. You can also find information on weekly harmful algal bloom forecasts reported by the EPA.
• Avoid water with visible algae or pond scum, or with dead fish, birds, or other wildlife nearby.
• Pay attention to posted signs. If there’s a ‘no swimming’ sign posted, it’s for a good reason!
• If your dog has been swimming in contaminated water, rinse their fur with fresh water from a hose or tap as soon as possible. You want to try to remove harmful toxins from his or her fur before they’re ingested. (Note: this step is in addition to, not instead of, taking your dog to the vet.)

Keep in mind that if you use an algaecide on the water, it will kill cyanobacteria, but toxic strains of cyanobacteria release high levels of toxins as they die. These toxins may persist in the water for several weeks after the cyanobacteria are gone.

What is the prognosis for blue green algae toxicity in dogs?

Unfortunately, prognosis for dogs exposed to blue green algae is not good. Although it is not 100% fatal, death can occur quickly and treatment is not always successful.

Where can I learn more about blue green algae and dogs?

If you have questions or concerns about the hazards of blue green algae for your dog, please speak with your veterinarian or read more about toxic algal blooms at USGS.gov (United States Geological Survey).

For more images of cyanobacterial blooms, please visit Cyanosite.com, a research site supported by Biological Sciences at Purdue University and by Wichita State University. A special thank you to Mark Schneegurt at Wichita State University for permission to share images of cyanobacterial blooms so that we can inform our readers about blue green algae.

Please help spread the word about this toxin that is dangerous to dogs so that other pet parents are informed. If we all work together, we can help keep our dear dogs safe and prevent future tragedies.

What questions do you have about blue green algae and dogs?

Please comment below.