Japanese broad tapeworm larvae found in Alaskan pink salmon
What it found
A tapeworm larva that can infect people was found in the muscle of a wild pink salmon caught in Alaska.
This is the first report of this larva in North American salmon.
What they found
Studies in people
Human cases underestimated
Recent studies using molecular methods suggest the number of human cases caused by this tapeworm may be much higher than previously thought. About 2,000 cases have been reported, mainly from northeastern Asia.
Animal and lab studies
Larva found in pink salmon
A single tapeworm larva was found deep in the muscle of a pink salmon caught in Resurrection Creek near Hope, Alaska. It was 8 to 15 mm long and still moving.
Larva identified by genes
The larva's DNA matched the Japanese broad tapeworm almost exactly, confirming it was that species. This is the first time this larva has been reported in North America.
Other findings
Salmon as infection source
The authors say salmon from the Pacific coast of North America may be a source of human infection. Because salmon are often shipped on ice without freezing, the larvae may survive transport and infect people in other regions.
What the authors conclude
“Therefore, salmon from the American and Asian Pacific coasts and elsewhere pose potential dangers for persons who eat these fish raw.”
Also in their conclusions
- They say this report provides additional evidence that salmon from the Pacific coast of North America may represent a source of human infection.
- They advise that to control this foodborne parasite, the sources of human infection need to be detected and current knowledge of the distribution and transmission of human-infecting tapeworms needs critical revision.
How it was done
The Japanese broad tapeworm is a common cause of human infection, and eating raw fish is becoming more popular. The authors wanted to warn doctors and scientists that salmon from the Pacific coast of North America could be a source of human infection.
In July 2013, they examined 64 wild Pacific salmon of 5 species from south-central Alaska, including 23 pink salmon. They sliced the muscle into thin pieces and looked at the internal organs under a magnifying glass.
What it can’t tell you
- This study looked at only 64 salmon and found just one larva, so it cannot show how common this tapeworm is in salmon.
- It cannot show whether eating raw salmon from this area will definitely cause infection in people.
The paper
- Title
- Diphyllobothrium nihonkaiense Tapeworm Larvae in Salmon from North America
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Kuchta R, Oros M, Ferguson J, Scholz T (2017). Diphyllobothrium nihonkaiense Tapeworm Larvae in Salmon from North America. Emerging infectious diseases. doi:10.3201/eid2302.161026Free full textPubMed 28098540DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error