D. E. Larsen, DVM
When I was growing up in Coos County one rarely encountered a Coyote, except on the high ridges. We didn’t think much about it at the time. That was just the way it was. I remember the first coyote I saw, on the top of Sugarloaf Mountain, on a cold morning Jeep ride with Uncle Robert.
Twenty years later coyotes had moved into the valleys and were heard regularly and encountered with little effort if hunting them. They had become a significant problem to sheep ranchers, and an occasional brave one would come close enough to the barnyard to snatch a chicken.
My Uncle Duke’s explanation for the change was probably the most accurate. I didn’t have a full understanding at the time but would later come to appreciate his wisdom. In my younger years, 1940s and early 1950s, all the creeks in the area were full of spawning salmon and steelhead in the fall and winter. Dead, spawned out, fish were present on the riverbanks and all the creek banks. Later in the 1950s and 1960s, commercial fishing for salmon moved from the steams to the ocean. Spawning fish numbers decreased and dead fish were only occasionally encountered on most streams.
Duke’s opinion was that when the streams were chuck full of fish the coyotes would have easy access to salmon and would die from the disease. The only viable populations thus existed on the high ridges far removed from the spawning streams.
Salmon Disease (or Poisoning) is a complex disease of all canines. It occurs approximately 7 days after a dog (or coyote) consumes infected raw salmon, trout or steelhead. The fish carry a larva of an intestinal fluke. The fluke causes only mild disease and can infect a number of species, but the fluke also carries a rickettsia. It is this rickettsia that makes all canines ill and is the cause of Salmon Disease.
Salmon Disease is treatable if it is caught in time. Ninety percent of dogs (and coyotes) will die within 7 – 10 of becoming sick if they are not treated. Survivors may be immune for long periods if not for a lifetime although there are exceptions to this immunity.
I was on a farm call, talking with Dick Rice. Dick owned a ranch on the Calapooia River. His ranch was one of the early pioneer ranches in the area.
“Doc, I have been having a heck of a problem with coyotes the last couple of years,” Dick said. “It seems to be the same coyotes most of the time. He has only three toes on one foot. He catches any lamb left out of the barn overnight. Can’t trap him, he is too wise.”
Dick was at his wits end on how to deal with this bandit. I related my Uncle Duke’s opinion on the shift of the coyote population into the Western Valleys. He listened with interest but just seemed to take it in as a story. I finished with the calf we were treating, loaded up and returned to the clinic.
I never gave the conversation much thought after that until I bumped into Dick outside of Thriftway one afternoon. Dick had hurried to catch up to me in the parking lot. It was apparent that he wanted to talk.
“Hi Doc, how have you been?” he said, a little out of breath. “I have wanted to talk to you about that Old Three Toes.”
“Aw, yes, I remember you talking about him,” I replied.
“You know, I got thinking about the story you told about Salmon Poisoning. One night after work, I stopped in here and bought a hunk of salmon tail. I have an old burn pit and garbage pile on the far side of the pasture behind the house. I took that salmon out there and put it on the edge of that pile. It was gone the next morning.”
“And Doc, that was a couple of months ago. I have had no more coyote problems, and Old Three Toes is gone. I have not seen his tracks anywhere. Can’t thank you enough for that story.”
“I’m glad it helped you, Dick. You can thank the observation skills of an old farmer for the information. I am not sure that I would have ever put that information together to come up with that conclusion,” I replied.
Photo by DAVID NIETO on Unsplash
Memoirs of a Country Vet 
Do bears get salmon disease?
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Yes is the simple answer. So how do bears survive on a fish diet.
Of course, the pictures of bears in the Alaskan rivers always come to mind. There is no salmon disease in Alaska. The snail in the life cycle has a limited geographic distribution.
I think in Oregon, bears likely consume fish while they have maternal antibodies still present. That allows them to develop their own antibody protection.
Here is an interesting article on the topic, the abstract gives good information.
https://wildlife.onlinelibrary.wiley.com/doi/abs/10.1002/jwmg.21502
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Thanks for the link. It sounds like bears, and dogs, could be possibly be vaccinated against it.
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The limited geographic distribution of the disease makes it unprofitable for a vaccine. In the late 1970s or early 1980s there was a vaccine produced by a lab in Portland. It could only be used in Oregon.
I ordered a vial but it looked so bad (floaters) that I never used it. Some veterinarians used it. I have no concept of how efficacious it was in dogs.
Many people (especially fishermen) will purposely fish their dogs. It generally imparts lifelong immunity. The problem is there may be several variants of the bacteria and dogs can therefore get the disease 3 times. That is probably correct, but I think most case get all three variants when infected and they do get life long immunity.
In 40 years, I saw a dozen cases of dogs getting salmon disease twice (with a confirmed diagnosis each time). I saw several cases of a dog getting it three times, but in each of those cases, at least one time was a subjective diagnosis (not confirmed).
The other problem is sometimes a dog will die from salmon disease, even with early diagnosis and appropriate treatment. That happened to my brother’s dog in Myrtle Point.
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Lavinia, One problem with salmon disease is it occurs only on the west coast, from northern California to southern BC, and similar latitudes on the east coast of Russia. When I was in vet school, you could only find a few sentences on the disease in textbooks. Veterinarians removed from the endemic areas are all but ignorant of the disease.
When a publication came out on the diagnosis and treatment of parasitic diseases a number of years ago, there was no mention of the disease. The editor was in Virginia, or West Virginia maybe. I sent him an email scolding him for the omission (he said the contributor who was to write on fluke diseases missed the deadline).
The problem today is with how much travel exists in the population. I told him that a dog traveling with a family from Virginia could consume fish guts along the river bank in Sweet Home on Monday, and he could be home in Virginia by the following Monday when he would start being sick with the disease. With good lab work, a veterinarian in Virginia could make the diagnosis, but it would be delayed by one or two days compared to a northwest clinic. Then he goes to the books and finds very little written about treatment, and antibiotic selection is critical in the treatment.
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That is a real problem with travel and diseases endemic to a small area. That was a good call to contact the Virginia editor about the omission.
Not related except for travel, but when I was young, we never heard of Giardia in streams and ponds back east. Never worried about where we swam or what stream we drank out of, except my mother. None of us got sick, maybe we were just lucky. I first became aware of Giardia when hiking Mount Washington in New Hampshire almost 30 years ago now, and seeing all kinds of warning signs along the headwaters of the Ammonoosuc River. Hikers and their dogs defecating along the trails up on the mountain helped contaminate the water. Things get picked up and travel on back home and elsewhere.
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Cheers – very interesting piece. 🙂
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Have a wonderful holiday, Doc!
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Thanks, GP! We will have most of the family, plus a few, for dinner. Somewhere between 15 and 21 folks. Busy, but a fun busy.
Merry Christmas to you and yours also.
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Outstanding!
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