New Brunswick

Blue-green algae confirmed as cause of dogs' sudden deaths in Fredericton

Necropsy results show blue-green algae caused the deaths of three dogs playing near the St. John River more than a week ago.

Despite finding, provincial officials say water is still safe for swimming and other recreation

From left to right, Sookie, Peekaboo and Nike all died suddenly only days apart after playing in the St. John River in the Fredericton area. (Photo: Submitted)

Necropsy results show blue-green algae caused the deaths of three dogs swimming or playing near the St. John River in late July.

Provincial officials say this doesn't mean dogs or people should avoid the water, but they should be careful.

All three dogs died immediately after visiting the water's edge in the Fredericton area.

Two dogs ate some aquatic plants onshore at Carleton Park on Fredericton's north side. The third dog was swimming near Hartt Island RV Resort, 14 kilometres west on the St. John River. 

Dr. Jim Goltz, the province's top veterinarian, said two necropsies were performed last week — on a dog from each site — and the results came in Thursday night.

Despite the confirmation blue-green algae, or cyanobacteria, were responsible for their deaths, Goltz didn't say dogs shouldn't be going in the river.

Owners should be wary, however, of letting their pets near any areas of the St. John River that have turned a bluish green, he and other officials said at a news conference.

Goltz wasn't aware of any other animals, including wildlife, affected by blue-green algae this summer.

Blue-green algae can kill

The last case fatal to a dog was in 2010, when a Labrador puppy died from blue-green algae toxicity after swimming in the St. John River below the Mactaquac Dam in the Island View area.

Goltz said blue-green algae grow in warm conditions, when water levels are low and produce different toxins that can affect the brain.

Necropsy results show blue-green algae caused the deaths of three dogs swimming or playing near the St. John River in late July. 0:58

"These can kill animals within half an hour of exposure and after the toxin has been ingested," Goltz said earlier.

They can also produce toxins that damage the liver. 

'It looks like green paint has been poured onto the surface of your lake."- Don Fox, Department of Environment

Dr. Don Fox, manager of water sciences for the Department of Environment and Local Government, said there was no indication of an algae bloom before the dogs in the Fredericton area died.

"They're naturally occurring," he said. "Their presence [is] not necessarily anything bad."

But a bloom can happen quickly, he said.

"Algae blooms in some of our lakes are very striking when you get a full bloom," Fox said. "Your lake can change colour overnight from a nice blue-water lake to bright green, and it looks like green paint has been poured onto the surface of your lake."

He said these blooms are a concern and should be reported. 

"Conditions for cyanobacteria growth include warm temperatures, lots of sunlight, low water levels and nutrients."

Fox identified phosphorus and nitrogen as the nutrients that help create perfect conditions for the growth of cyanobacteria.

After the dogs' deaths were reported, the Department of Health investigated the two sites where the dogs were swimming for potential health risks to humans.

Safe for recreation

Dr. Na-Koshie Lamptey, regional medical officer of health, said she wasn't aware of any New Brunswick cases where people have died after coming in contact with blue-green algae through recreational activity.

People have become sick consuming the algae in high concentrations in drinking water, she said.

While recommending people be careful, she said there's no reason to avoid swimming or other recreation in the water.

"To be clear, while it has been determined that blue-green algae is present in some areas of the St. John River, we are by no means saying that you cannot continue to use the river for recreational purposes," Lamptey said.

Lamptey encouraged recreational water users to visually scan the water before entering, never swallow the water, bathe or shower to remove anything that could be irritating, and never swim in the water with an open wound.

With files from Shane Fowler