Diphyllobothriasis after eating raw salmon

An 11-year-old boy in Hawaii passed mucus and a moving object in his stool. The object was identified as a segment of the fish tapeworm Diphyllobothrium species which is not indigenous to Hawaii. Diphyllobothrium ova were also found in the stool. The only raw fish he recalled eating in previous months were tuna sushi and lomi-lomi salmon which usually contains raw but previously frozen salmon. Of these two fish, only salmon which is not native to Hawaiian waters, has been incriminated as a significant source of diphyllobothrium fish tapeworm infection. Freezing kills this parasite, however, we speculate that the raw fish in the lomi-lomi salmon that our patient had eaten had not been pre-frozen or was not adequately pre-frozen. Eating raw salmon without certainty that it has been adequately pre-frozen carries the risk of diphyllobothriasis or fish tapeworm infection.