Are you traveling with a dog to the northwest US, western Canada or Alaska? In 2018, we drove our 2552 through Canada to Alaska, along with our Labrador Retriever, Maggie. We spent a good deal of time fishing for salmon -- and other fish -- and somewhere along there, Maggie began to have rectal bleeding. When we returned to Tennessee, we consulted our vet, knowing that she might have gotten into something "exotic". The vet sent samples to the University of Tennessee, looking for parasites, and we put her through a course of Panacure, a broad spectrum wormer. The vet tried two different antibiotics, but nothing worked.
About three months ago, we changed vets and I went over Maggie's history with the new doctor. When I explained her problem and our trip to Alaska, she asked, "What about salmon poison?" After I said, "Huh?" she explained that it's only found in raw salmon from the waters of northwestern North American and it's only toxic to dogs. Here's a link: https://www.vetmed.wsu.edu/outreach/Pet-Health-Topics/categories/diseases/salmon-poisoning#:~:text=Salmon%20Poisoning%20Disease%20is%20a,the%20parasite%20is%20relatively%20harmless
She asked if Maggie had eaten raw salmon, and I confessed that I'd fed her bits as I'd filleted our catch. After she explained that though the parasite could be killed, leaving the infection, she prescribed the correct antibiotic. Lesson learned: if you're taking your dog to the northwest, watch what she eats! No raw salmon. Who knew?