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A sign marks a closed beach on Grand Lake in Oakfield Provincial Park in Oakfield, N.S., June 10, 2021.Andrew Vaughan/The Canadian Press

Dog owners in Nova Scotia should be on the lookout for blue-green algae in lakes and ponds this summer after two dogs died following a potential exposure to the bacteria, a veterinarian at the clinic that treated the fatally ill animals said.

Juanita Ashton with the Elmsdale Animal Hospital said one of the two Golden Retrievers was dead and the other was suffering from seizures and diarrhea when they arrived at the clinic north of Halifax.

The cause of the illness has not yet been confirmed, but she said the symptoms were consistent with an exposure to toxic blue-green algae blooms.

“The big risk for dogs is when they go swimming in it, they’re usually ingesting a lot of the water,” she said. “If they ingest enough of it, it is potentially fatal.”

Residents of the area around Grand Lake, near Enfield, N.S., were informed of the potential danger in the water after one person was hospitalized and two dogs died last week.

Blue-green algae produce toxins that pose a range of health threats to humans and animals.

Dogs can develop mild skin rashes or suffer from organ failure and death, Ashton said.

If a dog consumes enough of the bacteria, veterinarians can offer supportive treatments but “it’s very hard to get these dogs to a normal state of health,” she said.

While the older dog had died before arriving at the clinic, the younger puppy was extremely sick, Ashton said.

“It was so devastating,” she said. “They were just the best pet owners. They were very responsible.”

Nova Scotia’s Environment Department said people with wells that have a depth of 30 metres or less and are located within 60 metres of the lake should not use their well water for drinking, bathing or cooking until further notice.

An official with the department said the water is being tested for pesticides, organic materials and petroleum hydrocarbons, but the toxin produced by blue-green algae is the likeliest cause.

“A picture was taken the first evening … and it has that quite vibrant colour to it, suggesting it is blue-green algae,” Deputy Environment Minister Julie Towers said in a briefing on Friday, adding that it came after an unusually warm series of days.

The frequency and size of the blooms may be linked to climate change, she said.

“Algae like any plant responds to warmth. We’re getting warmer. We’re seeing climate change effects,” Towers said. “I suspect we’re going to have more blooms in more sites.”

For dog owners, Ashton said it’s important to keep an eye out for a bright green scum on lakes and ponds, especially during a heat wave.

Toxic blue-green algae can range in colour from bright neon green to turquoise, olive-green, or even red, according to Nova Scotia Environment Department’s website.

Blooms can look like fine grass clippings in the water or a large carpet of scum on the surface. The algae can be seen floating on the surface or suspended in the water.

“When there are hot days, not windy – this is when the bacteria likes to form on the top of water,” Ashton said. “In Grand Lake, it’s a big, giant lake, so it’s not going to be all over that lake but it could be at the shoreline.”

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