After three dogs died suddenly this summer after being exposed to blue-green algae in Fredericton’s St. John River, veterinarians are warning the public about the dangers of the toxic bacteria.

Two of the dogs suffered convulsions and vomiting, according to witnesses. Water tests later confirmed the presence of the potentially deadly microbe known as cyanobacteria.

New Brunswick is not the only province to confirm blue-green algae in some of its bodies of water. Officials in Ontario and Nova Scotia have issued public advisories this summer as well, asking residents not to swim in contaminated areas in some cases.

Researchers at the University of Alberta said that there were 246 bodies of water in Canada with the bacteria in 2017.

While blue-green algae looks like algae, Dr. Rebecca Greenstein, a veterinarian, told CTV’s Your Morning that its name is a “misnomer” because it’s actually bacteria.

Water contaminated with the bacteria often has a scum on its surface that looks like pea soup or paint, which blocks out sunlight for other aquatic plants. The microbes produce toxins that are harmful to the liver and nerve tissue.

Blue-green algae growth is boosted by “warm long days and industrial runoffs and areas where there is a lot of phosphorous and nitrogen,” Dr. Greenstein said, which is why contamination is more likely during the summer months.

When humans and pets are exposed to the bacteria, they often develop skin irritation, rashes and blistering. But the bacteria can become deadly if swallowed, and pets may be less likely to be deterred from entering a body of water with a soupy scum on its surface than humans.

“Usually, it’s a pretty rapid time to onset (for pets),” Dr. Greenstein said. “Within at least an hour, you’ll see convulsions, walking a little bit strangely and they can go into breathing paralysis and die that way.”

Other symptoms to look out for include diarrhea, vomiting, jaundice and disorientation.

The trick to preventing pets from succumbing to the deadly bacteria is to bring them to a veterinarian before they start showing symptoms.

“If your dog runs off and ends up just covered in blueish-green stuff, then you want to go directly to a vet, where we would induce vomiting and give them activated charcoal,” Dr. Greenstein said. “There is no specific antidote, but rapid treatment is very important.”