Salmon poisoning disease (SPD) is a fatal disease of dogs and other canids caused by infection with a type of rickettsia, Neorickettsia helminthoeca.[1] It results from eating raw salmon, trout, or Pacific giant salamander and is found in the Pacific Northwest. These fish and amphibians are infected with metacercariae of a fluke, Nanophyetus salmincola through an intermediate host, the snail Oxytrema plicifer. The fluke attaches to the intestine of the dog and the rickettsiae are released, causing severe gastrointestinal disease and systemic infection.
Neorickettsia elokominica, carried by the same fluke, causes a similar disease known as Elokomin fluke fever (EFF) in canids, bears, raccoons, and ferrets.[2]
Symptoms of SPD begin about one week after eating the salmon and include vomiting, diarrhea, loss of appetite, depression, high fever, and enlarged lymph nodes. Untreated, mortality reaches 90 percent.[3] Death occurs seven to ten days after symptoms begin.[1]
Diagnosis is through finding the fluke eggs microscopically in a stool sample. A needle aspiration biopsy of an enlarged lymph node will reveal rickettsial organisms within macrophages in many cases.[4] The rickettsial infection can be successfully treated with antibiotics such as tetracycline, and the fluke infection can be treated with fenbendazole.
EFF has less severe symptoms than SPD, with less gastrointestinal signs and more lymph node involvement. The mortality in untreated cases is about ninety percent.[2]
A similar disease has been identified in Brazil.[5]