Two dogs likely died after ingesting harmful algal bloom toxins earlier this month from a private Vermont pond, providing a tragic reminder to the public to be on the lookout for changes in the water.

With waters warming and heavy rains providing nutrients to lakes and ponds, harmful algal blooms are on the rise across the state.

Officials and researchers are warning the public to keep track of their pets, which in some cases are more susceptible to toxic algal blooms because they drink more water and lick their fur.

Angela Shambaugh, an aquatic biologist with the Vermont Department of Environmental Conservation, said the dogs that died in her state either drank the water, which was impacted by a bloom, or ate some of the algae that had washed ashore.

“It’s not often that the owners go to the expense to learn what happened,” Shambaugh said. “An autopsy and water samples confirmed that there was a cyanobacteria toxin present, and that’s likely what killed the dogs.”

Shambaugh said dog deaths from harmful algal bloom toxins, or cyanobacteria toxins, are rare in Vermont, but as the state found out this summer, it can happen.

“We want to raise awareness to remind folks the potential for these toxins is here in the Northeast,” Shambaugh said.

But they’re not as rare in the United States as one might think.

A study published by the National Institute of Health examined 368 dog deaths from toxic algal blooms between the 1920s and 2012. The report says those incidents, which came from three national databases, “likely represent a small fraction of cases that occur throughout the U.S. each year.”

Livestock are also at risk, said Karyn Bischoff, a toxicologist with Cornell University’s College of Veterinary Medicine. Small watering holes and ponds, especially in the Midwest, can become filled with cyanobacteria blooms.

“For pet owners, you want to avoid it, that’s pretty much all there is to it,” Bischoff said.


Harmful algal blooms and their toxins can kill wildlife and also pose health risks for humans. A bloom is seen on Binder Lake in Iowa.


Two toxins, microcystin and anatoxin, are of the most concern in New York. Microcystin is a liver toxin and anatoxin is a neurotoxin.

Bischoff said both are “surprisingly fast-acting,” especially if a dog licks its fur and gets a concentrated dose.

“In one case of cyanobacteria (poisoning), the person had two pet dogs,” Bischoff said. “They came out of a lake covered with cyanobacteria. He (the owner) grabbed the hose and hosed one of them down, but by the time he went to hose the other one, it was dead.”

Those poisoned by microcystin experience pooling of the blood.

Those poisoned by neurotoxins experience over-stimulation, Bischoff said. An animal may go through excessive salivation and tearing, urination and diarrhea. The nerves are firing so quickly that they wear out, and eventually the animal dies from respiratory paralysis, she added.

Bischoff has also researched cyanotoxin poisoning in livestock. In Oklahoma, where there are many small ponds for cows to drink water, Bischoff observed a cow walking away before stumbling and dying. It had died from consuming microcystin.

What to do

If you didn’t keep your dog on a leash before checking the water and it jumped into a bloom, Bischoff said the first thing to do is get it out of the water and rinse it off.

Not all cyanobacteria blooms have toxins, either. Bischoff said to monitor the dog and look for symptoms.

If you do suspect your pet has ingested toxins, get it to the vet.

Bischoff said veterinarians may want to test for liver enzymes. They may give the pet a dose of activated charcoal or something similar, which binds to the toxins and helps them pass through.

If the dog ingested a neurotoxin, the vet may sedate the animal until it gets through the extreme stimulation. The goal will be to keep the animal breathing, too.


Greg Boyer, a professor and scientist and SUNY College of Environmental Science and Forestry, has been studying cyanobacteria for decades.

Every once in a while, a pet owner or vet will reach out to him about a dog that is ill or dead, possibly from cyanotoxins.

Boyer said he is working with some vets on a possible urine analysis as a way to test a sick dog for the toxins. It’s not easy, however.

“Most people don’t realize that type of work, what’s called ‘untargeted discovery,’ is very, very time consuming,” Boyer said. “We’ve had samples we’ve worked on for six months.”

Once an animal ingests the toxin, the body will try to detoxify it, Boyer explained. That could modify the toxin, making it difficult to test for directly.

Testing the water source is also costly and can be time consuming.

That’s what is frustrating for Bischoff when trying to diagnose an animal that could be poisoned by cyanobacteria toxins. The state does not test every bloom, so without waiting for clinical signs, vets have no way of knowing if a pet was exposed to the liver or neurotoxin.

“It is very hard for me with the way that the database is set up for reporting,” Bischoff said.

Jackie Lendrum, a scientist with the DEC’s division of water, said some samples are tested for microcystin, but the state urges people stay out of any suspicious-looking water.

“The most important message is to know it, avoid it, report it,” Lendrum said. “We can’t reiterate enough to folks. Don’t wait for lab results.”

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Reporter Gwendolyn Craig can be reached at (518) 742-3238 or gcraig@poststar.com. Follow her on Twitter @gwendolynnn1.


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