Salmon, steelhead present hazard to dogs

BEND, Ore. – In early September, it became clear to Shana Brooks that something was wrong with her 10-month-old golden retriever, Abby.

The happy, healthy dog suddenly stopped eating and drinking, and she became lethargic. A trip to see Dr. Taylor Douglas of Bend and some blood tests revealed nothing, Brooks said.

Abby’s condition continued to decline, and a second trip to the vet’s office resulted in exploratory surgery, where doctors found swelling, but little else that would lead them to a diagnosis, she said.

“She needs to get better because I’m leaving for Alaska for a week on this vacation,” Brook told the veterinarian.

When Dr. Douglas learned she was going fishing, the light bulb went on.

“He looked at me and he said, ‘Do you fish for salmon?’ ” Brooks said.

When she answered yes, he asked if Abby had eaten any salmon.

She had. Two weeks earlier, Brooks and Abby were on a fishing trip to the Umpqua River in southern Oregon when Brooks noticed her pup gnawing on a fish head.

“I took it away from her, threw it in the river and didn’t think anything of it,” she said.

After hearing that story, Douglas had a pretty good idea of the dog’s affliction: salmon poisoning, a rare condition that kills about 90 percent of affected dogs if left untreated.

At the time, Abby was 12 days removed from eating the fish, and her life was in danger. She stayed at the hospital for a week, receiving fluids, antibiotics to fight the bacteria, deworming treatment to battle the parasite, and plasma because she had lost so much blood.

She couldn’t walk or eat, so Brooks and the vet staff force-fed her. Eventually, Brooks took her home.

Abby survived. She lost a lot of weight, but eventually she began eating again and recovered.

Salmon poisoning is specific to the region west of the Cascade Range in Oregon, Washington, California and British Columbia, said Colin Gillin, veterinarian for the Oregon Department of Fish and Wildlife.

It originates in a bacterial organism called neorickettsia, which is carried by a specific parasite called a fluke that thrives in the waterways of the western Pacific Northwest.

The story of how the bacteria infects a dog plays out like Russian nesting dolls.

“There’s four players in this besides the dog,” Gillin said. “There’s the fish, and then there’s a snail, and a fluke. And the fluke infects the snail, and the fish eats the snail and gets the fluke. Inside the fluke are some bacteria, and the bacteria are what messes up the dog.”

Only canids — dogs, wolves, foxes, coyotes — are affected by the bacteria, Gillin said. And only salmon-type fish including steelhead — anadromous fish that swim upstream to breed — seem to provide a suitable home for the fluke.

Only certain species of aquatic snail can carry the fluke to the fish, he said. And the fluke is the most specific of all the hosts; only one genus and species of the fluke carries the bacteria.

If a dog eats a fish that contains the parasite, the fluke will release eggs that enter the animal’s intestinal tract, where they release the neorickettsia. Dogs that are infected will usually begin to show symptoms within one to three weeks, and symptoms typically include vomiting, diarrhea, swollen lymph nodes and fever.

Owners whose dogs are showing those kinds of symptoms should get their animal to a vet immediately, regardless of the reason for the illness, Gillin said. An owner with an inkling that a dog has eaten uncooked salmon, either from a garbage can, a kitchen counter or a campsite, should inform the vet of that possibility, he said.

“If it’s got any kind of gastrointestinal symptoms,” Gillin said, “it’s in a losing battle with a bacteria.”

What made Abby the golden retriever a tricky case was that she wasn’t showing symptoms typical of salmon poisoning, Douglas said.

“Abby wasn’t running a fever, wasn’t having diarrhea and didn’t have enlarged lymph nodes, peripherally. So the signs weren’t there.”

People cleaning fish should take care to ensure their dogs can’t get to them, he said.

“If I would’ve known what it was, I would’ve been like, ‘Oh, she got into this salmon,’ and they would’ve put her on an antibiotic and that would’ve been the end of it,” Brooks said. “Instead, she almost died, and I spent all this money and she had to have surgery.

“It was an awful thing to go through,” she said. “I don’t want anyone else to go through it.”