Salmon Poisoning

What is salmon poisoning?

Salmon poisoning is a bacterial infection in dogs that occurs when dogs eat raw or undercooked salmon, trout, steelhead, or Pacific giant salamanders infected with a fluke (parasitic flatworm) called Nanophyetus salmincola.

This flatworm is generally harmless to dogs, unless it is infected with bacteria called Neorickettsia helminthoeca. After a dog eats raw fish or salamander, infected flukes embed in the dog’s intestines, allowing the bacteria to enter the bloodstream. The bacteria spread to various organs, resulting in signs of salmon poisoning.

Salmon poisoning is most commonly seen in Washington, Oregon, northern California, and southern Vancouver Island (Canada). The disease is mainly seen in domestic dogs, wolves, coyotes, and foxes, although it has also been reported in black bears. Cats do not appear to develop salmon poisoning. Humans may develop mild gastrointestinal signs but do not develop salmon poisoning.

What are the clinical signs of salmon poisoning?

Signs of salmon poisoning are typically seen within a week of the dog eating infected raw or undercooked fish or salamanders. Common signs include:

• Lack of appetite, vomiting, weight loss
• Diarrhea (which may include blood)
• Fever
• Weakness
• Enlarged lymph nodes
• Discharge from the eyes or nose
• Increased respiratory rate, increased heart rate
• Muscle tremors
• Seizures

If the infection is not treated, most dogs will die within two weeks. If you suspect your dog may have salmon poisoning, immediately call your veterinarian or Pet Poison Helpline, a 24/7 animal poison center, at 1-800-213-6680.

How is salmon poisoning diagnosed?

Salmon poisoning is suspected when dogs in the Pacific Northwest develop the expected signs after eating raw fish or salamanders. Finding the fluke’s eggs in the dog’s fecal sample (stool) helps to support the diagnosis. Although the fluke itself does not directly cause salmon poisoning, its presence in a dog showing typical signs is highly suggestive of salmon poisoning.

To confirm the diagnosis, a sample of the enlarged lymph nodes may be obtained using a needle. Bacteria may be seen microscopically in the cells of the lymph node. A special test called PCR may be used to directly detect DNA of the bacteria in the lymph node.

How is salmon poisoning treated?

Treatment involves antibiotics to control the bacterial infection and medications to kill the flukes. Dogs with severe signs may require hospitalized care, including intravenous fluids, anti-nausea medications, anti-diarrheal medications, or even blood transfusions.

What is the prognosis for salmon poisoning?

With appropriate treatment, most dogs recover completely from this disease. Early diagnosis and treatment are key to a successful outcome. Sadly, death is common in dogs that do not receive appropriate treatment.

How can salmon poisoning be prevented?

Do not allow your dog to eat raw fish or salamanders, especially in the Pacific Northwest. When fishing, ensure dogs do not have access to the raw fish or salamander or to fish and salamander parts. Monitor dogs closely when around bodies of water to prevent them from eating fish or salamanders. Restrict access to areas where fish or salamanders may be disposed of, including trash cans and fishing docks.

Pet Poison Helpline, an animal poison center based out of Minneapolis, MN, is available 24/7 for pet owners and veterinary professionals that require assistance treating a potentially poisoned pet. The staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals, and exotic species. As the most cost-effective option for animal poison control care, Pet Poison Helpline’s per-incident fee includes follow-up consultations for the duration of the poison case. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at www.petpoisonhelpline.com.