[2] It results from eating raw salmon, trout, or salamander and is common in the Pacific Northwest.

These fish and amphibians are infected with the larvae of a fluke, Nanophyetus salmincola through an intermediate host, the snail Juga plicifera (Oxytrema is an obsolete genus).

The larvae attach to the intestine of the dog and the rickettsial bacteria are released, causing severe gastrointestinal disease and systemic infection.

[3] 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.

A needle aspiration biopsy of an enlarged lymph node will reveal rickettsial organisms within macrophages in many cases.