What Happens in a Dog's Body with Cyanotoxin?

By Dr. Jennifer Coates, DVM

What Happens in a Dog's Body with Cyanotoxin?

When it’s hot, very few dogs can resist taking a dip and probably a sip from whatever water is nearby. Usually, that’s not a problem, but if the water is home to large numbers of blue-green algae (also called cyanobacteria), owners should do everything in their power to keep their dogs away.

Here’s why.

Many species of blue-green algae produce toxins that collectively are called cyanotoxins. 


In truth, there are more than 30 species of potentially dangerous blue-green algae that produce several different types of toxin, but for our purposes, we can divide cyanotoxins into two main categories:

  1. Neurotoxins—toxins that primarily affect the nervous system
  2. Hepatotoxins—toxins that primarily affect the liver

Routes of Exposure


The most serious damage from cyanotoxin occurs when a dog ingests blue-green algae. This typically happens when a dog drinks from a contaminated body of water but can also be associated with swimming when dogs either inadvertently get a mouthful of water or try to lick themselves clean after they get out.

Blue-green algae primarily live in stagnant or slow-moving bodies of fresh water that are warm and carry a large nutrient load (e.g., are polluted with fertilizer, animal waste, etc.). Salt or brackish water cyanotoxin poisonings are possible but occur much less frequently. Most cases occur in the late summer.

When people swim in blue-green algae contaminated water, we can develop skin rashes, eye irritation, ear inflammation, and respiratory problems. Similar symptoms probably occur in dogs as well, but they tend to be overshadowed by the effects of neurotoxins and hepatotoxins.

The Effects of Blue-Green Algae Neurotoxins on Dogs


Blue-green algae neurotoxins take effect very quickly.

They work by overstimulating the nervous system, which then essentially “wears out” over a short period of time if the dose is high enough.

Within minutes of ingestion, a dog develops symptoms like weakness, unsteadiness, muscle cramps, twitching, tremors, salivation, excessive tear production, urination, defecation, and difficulty breathing. Soon thereafter, severely affected animals may exhibit seizures, heart failure, and paralysis. Most die even if they receive prompt and appropriate treatment.

The Effects of Blue-Green Algae Hepatotoxins on Dogs


Blue-green algae hepatotoxins do their damage a little more slowly.

Symptoms can take hours or even a day or two to before they become evident but are all related to the death of liver cells and liver failure. Signs typically include some combination of lethargy, weakness, vomiting, diarrhea, abdominal pain, loss of appetite, pale or yellow skin and mucous membranes, and abnormal bleeding or bruising.

Supportive treatment for liver failure can be successful in milder cases, but most patients still die or are euthanized due to a poor prognosis. There is one report of a severely affected dog recovering after receiving the drug cholestyramine, but the link between treatment with this drug and the dog’s outcome isn’t clear.

Preventing Cyanotoxin Exposure


Since treatment for cyanotoxin exposure is so rarely successful, prevention is absolutely essential.

Blue-green algae blooms tend to look like a thick soup or a layer of paint floating on the surface of the water. Wind may push them into dense mats. Some types are a bright green color while others are more blue, brown, or a mixture of red and green. It is impossible to know whether an algal bloom with this appearance is toxic without laboratory analysis so it’s always best to be on the safe side and keep your dog (and yourself) away from any body of water that is potentially contaminated with cyanotoxin.

Related articles:
Summer Perils: Blue-Green Algae


Articles by Dr. Coates:
Kidney Disease – Say What? 
What Happens In The Dog's Body When The Kidneys Fail To Function Properly? 
Heat Stroke: What Happens In The Dog's Body? 
The Perplexities of Pancreatitis
The Other Side Of The Coin: The Cost Of Defensive Medicine
To Neuter Or Not To Neuter… That Is The Question
Don’t Forget the Physical Therapy
Common Misdiagnoses (Part 1)
Common Misdiagnoses (Part 2)
Picking the Right Dog to Breed
When Is It An Emergency?
Dog Allergies: Common, Commonly Misdiagnosed, or Both? 
Why Does The Spleen Get No Respect?
Protect Your Dog From Snake Bites
More Creepy Crawlies
Why I Dislike Inflammatory Bowel Disease
Salmonella – A Significant Problem, Or Not? 
What’s In the Vomit?
Cortisol: What Happens In A Dog’s Body When It Goes Awry?
What Happens In The Dog's Body With Zinc Toxicity? 
What Happens In The Dog’s Body: Xylitol Poisoning 
What Happens In The Dog's Body: Insulin 
When Is Hypothyroidism not Hypothyroidism? 
What Happens in a Dog's Body with Severe Vomiting?
What Happens in a Dog's Body with Hypothermia?

Comments

  1. Very informative post. I learned about the potential dangers of blue-green algae back when I first got my oldest dog so am always super careful about not letting my boys play around/in any bodies of water I'm not sure about.

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  2. Jack hates the water so at least I don't have to worry about him picking it up from swimming. He does sometimes like to drink out of puddles but I'm very careful to keep him away from them.

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    1. Puddles can potentially contain other things. But one cannot stop a dog from doing EVERYTHING. At least I can't.

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  3. Great information as always but this is one I do not have to worry with Madam as she hates getting her paws wet

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  4. Summer is coming here and the algae alerts will follow soon after. Thanks for an intelligent and sensible warning bout something very dangerous.

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  5. I thought that was something that only was found in exotic environs but we actually had a scare here with it this summer. It made the news to keep out of certain lakes.

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  6. This is very informative. I learn a lot from your blog that I share with family members.

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  7. Very good info and what to watch out for. I wasn't aware of cyanotoxins and will now be more aware of blue-green algae.

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  8. I just saw an episode on the Animal Planet channel about this toxin. I think a pet owner's dog had swallowed some of this toxic water. So sad and potentially deadly. Thanks for spreading the word about his toxic algae. Not everything in nature is safe.

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  9. It's amazing how toxic some water can be, especially still water. I can't help but think of all the animals down in the Carolinas following Hurricane Florence - I can't imagine how toxic some of that water has become!
    Love & Biscuits,
    Dogs Luv Us and We Luv Them

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  10. I can only imagine how dreadful it would be to lose a dog to cyanotoxins. Do you know if this problem is becoming more widespread? I'm thinking that global warming might be playing a role in it. I've had dogs all my life, and only heard about this in the last few years.

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  11. I don't think I'd heard of the difference in algae in water. I had no idea it was so toxic to animals who drank from it. It's a little scary all of the water "standing still" in SC and NC from the recent hurricane.

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