Salmon Poisoning can be a life-threatening disease of dogs, coyotes, and foxes. The classic symptoms are enlarged lymph nodes, fever, diarrhea, and vomiting. They do not always follow the classic symptoms and cases are sometimes tricky. The disease is diagnosed by visualizing fluke eggs in a stool sample. In some cases the stool is so watery – even getting a stoolÂ sample is difficult and there can be false negatives. Having a history of the dog having eaten raw Salmon or TroutÂ within the last 1-2 weeks also helps make the diagnosis.
The disease process is interesting because the fish itself doesn’t cause the disease, there is a parasite known as a fluke (specifically Nanophyetus salmincola), BUT the fluke itself doesn’t cause the disease, there is a bacteriaÂ (Neorickettsia helminthoeca) THAT CAUSES the DISEASE. Once the larval flukes reach the dog’s intestinal tract, they embed in the dog’s duodenal mucosa, and release the rickettsiae. The rickettsial organisms then spread through the bloodstream to the liver, lungs, brain, and lymphoid tissue.
If it is caught at a reasonable stage it can be treated. Most cases require hospitalization, intravenous fluid support, and intravenous antibiotics. Dogs that survive salmon poisoning will be immune to re-infection with the same strain. However, infection with an alternate strain can occur because there is no cross-protection.