Blue-green algae could have caused the death of a dog that was swimming in the St. John River in Fredericton, Canada, over the weekend, officials said Monday.

The dog started vomiting and collapsed after coming out of the river Saturday afternoon. The animal went into convulsions and died on the way to the hospital. Dr. Colleen Bray, the vet who examined the canine, believes the dog died after coming in contact with the blue-green algae.

“We don’t have any testing back, but the pattern of: very hot weather, actively swimming in the water during the hot weather, the symptoms that the dog presented with and the rapid onset of death all fit with a strong possibility of blue-green algae toxicity,” Bray said.

Asking people to keep their pets away from water, Bray added, “Because of that, I just wanted pet owners to be aware that there’s a strong possibility and keep their pets out of the water until we know more.”

In the meantime, health officials asked people to be cautious.

"If you see anything or smell anything that's unusual, it's best not to go in the water. We do recommend as well that you don't swallow recreational water, that you rinse after you get out and that you don't go in if you have open cuts or sores,” Dr. Cristin Muecke, the province's deputy chief medical officer of health, said.

Giving tips to ensure the safety of the pets, Dr. Jim Goltz, manager of New Brunswick's veterinarian laboratory service, said, "Make sure your dog is well hydrated before you go to the beach. Give it nice clean water in a clean bowl and make sure that it drinks that water well so that it's not thirsty before going around the water. It's also important to keep dogs under strict supervision when they are with you at the beach. Make sure they don't eat mats of vegetation. Those mats can often concentrate toxins of algae."

The incident comes a year after the same algae caused the deaths of three dogs swimming in the river. Dr. Goltz had said at that time the algae can produce toxins that can affect the brain and liver.

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

In this image, a dog's paw reaches through the kennel fence at the Queen Anne's County Department of Animal Service in Queenstown, Maryland, Jan. 24, 2008. Getty Images/Jim Watson