Dogs Are Contracting an Illness From California Lakes and Rivers

We’re well into spring, which means it’s officially “fishing season” for those who partake (and “finding out which of your friends have boats season” for those who don’t). But fishers, take heed: Raw fish is causing illness in Southern California dogs. Four pups have become seriously ill from salmon poisoning disease (SPD), which is caused by ingestion of raw fish. 

What is salmon poisoning disease?

Salmon poisoning disease is caused by a bacteria called Neorickettsia helminthoeca, which is carried by a parasite called Nanophyetus salmincola — and it’s a bit of a misnomer. SPD is caused by an infection, not a poison, and most cases in California are caused by trout, not salmon. “Dogs in Southern California usually become infected after exposure to raw trout, specifically trout that has been caught for sport fishing in local lakes, or water used to rinse raw trout,” Karen Ehnert, director of veterinary public health for the Los Angeles County Department of Health, said in a recent health advisory. 

“On March 22, 2024, an emergency veterinary practice in Pasadena, in Los Angeles County, reported four cases of Salmon poisoning disease in dogs that had become seriously ill,” Ehnert said. The dogs were hospitalized and all survived the illness. Each of the dogs had been exposed to raw fish fished from lakes in San Bernardino County, Orange County, and LA County.

In the four Southern California cases, dogs became sick after eating raw trout; in the past, dogs have also acquired SPD by digging up raw fish that had been buried for use as a fertilizer, licking raw fish, and drinking from a puddle where a raw fish had been rinsed. 

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The illness typically occurs in the Pacific Northwest, including Northern California, said Ehnert. “In Los Angeles County, most reported cases have been associated with raw trout that were caught during sport fishing in local lakes, which are stocked with trout that typically originate from farms in the Pacific Northwest.”

What are the symptoms of salmon poisoning disease?

Symptoms to look out for include vomiting, diarrhea, lethargy, fever, and enlarged lymph nodes. Sickness usually starts five to seven days after exposure. Dogs with SPD often need to be hospitalized, where they can be given care such as IV fluids, close monitoring, and antibiotic and antiparasitic treatment.

“Never feed raw fish caught during sport fishing to a dog,” Ehnert advises. If your dog does consume raw fish, closely monitor them for signs of illness and take them to the vet if they show symptoms of salmon poisoning disease.