Beware of salmon poisoning
Wendy River was a self-proclaimed fishing hobo. Her 2-year-old dog Pepper had been keeping her company on many trips to rivers and lakes since she adopted him over a year ago.
But Wendy became worried when Pepper, who &
had never been sick a day in his life,&
suddenly took ill with vomiting, diarrhea and depression. &
I think he&
s got the parvo,&
Pepper looked shriveled; his eyes were sunken, and his skin draped loosely across his thin frame. His head sagged low below his shoulders. &
Has Pepper ever been vaccinated?&
I made sure he got two distemper-parvo vaccines when I got him, but he has not had any since then,&
she replied. &
t know what to do, I just can&
t afford to put him in the hospital.&
I have to admit, it looks like parvo,&
I told her, &
but parvo is a disease we mainly see in dogs under a year of age, that have not been vaccinated. This could also be a case of salmon poisoning.&
Oh, I haven&
t been down to the river in over three months &
so Pepper hasn&
t been anywhere near salmon,&
Have you done any fishing in he last week?&
I asked. &
I just got back from a week of trout fishing at a lake up north.&
Could Pepper have got into any of the trout you caught&
Well, as a matter of fact, my partner fed Pepper a couple of trout heads&
Were they cooked?&
No, they were raw,&
Wendy slowly replied.
Well, salmon poisoning is not caused only by salmon and steelhead. Often the same hatcheries that raise salmon and steelhead also raise trout, and the trout can be infected with the organism that causes the disease. These trout are later stocked in area lakes, so dogs can become infected from eating raw trout as well as salmon and steelhead. Why don&
t we take a look at a fecal specimen and try to rule out salmon poisoning before testing for parvo?&
s fecal specimen tested positive for salmon poisoning. We gave Pepper a bolus of fluid under his skin, an intravenous injection of antibiotics, and sent Wendy home with a 10-day course of oral antibiotics. Wendy called a couple days later and reported that Pepper was feeling much better.
Salmon have been having a hard time of it lately. They&
ve had to put up with dams, drought, deforestation, run-off and more. The powers that be in Washington have even removed the distinction long granted to the wild salmon, lumping them in with their pen raised, corn-fed cousins when determining the success of the salmon runs in the nation&
t deserve to be labeled as dog killers &
in fact, they too are victims in the complicated life cycle that gives rise to the disease. The bacteria that infects the intestine in dogs that eat raw fish is carried within a fluke that develops in a freshwater snail.
When a young fish eats the snail, the fluke finds its way into the muscle of the fish where it encysts. When a dog consumes the raw flesh of an infected fish, the flukes are released, and they start to reproduce in the intestine, releasing the bacteria.
The bacteria infect and destroy the lining of the intestine and cause fever, vomiting, diarrhea, depression and swollen lymph nodes. Salmon poisoning can kill dogs if not diagnosed and treated within a few days of the onset of signs.
The diagnosis is confirmed by finding fluke eggs in a fecal sample from a sick dog. Treatment consists of antibiotics and supportive care. Dogs that survive develop immunity that can last several years. Dog owners need to know that area lakes can be sources of infection.
Every year in January, the Cole River fish hatchery takes steelhead from the hatchery and transplants them into Emmigrant Lake. These fish start to wash up on shore a few days later and present an almost irresistible temptation to dogs who visit the lake.
Owners should try to keep their dogs away from fish carcasses, and if their dogs develop diarrhea and depression, they should seek veterinary care within 48 hours. And maybe someday we will come up with a better name for the disease, and give those poor salmon a break.
Dr. Tesluk practices at Ashland Veterinary Hospital.