Diphyllobothriasis associated with salmon consumption in Pacific Coast states

A review of requests for niclosamide ( Niclocide or Yomesan ) made to the Centers for Disease Control Parasitic Diseases Drug Service indicated that an outbreak of diphyllobothriasis occurred in west coast states in 1980, and in the Los Angeles area in 1981. Our investigation of 52 infections that occurred in 1980 implicates fresh salmon (Oncorhynchus spp.) as the host for the Diphyllobothrium parasite in 82% of the persons interviewed. We describe here common symptoms of the infection, methods of fish preparation employed by infected individuals, and epidemiologic data. We suggest that changes in fish marketing practices and the popularity of uncooked or slightly cooked fresh salmon were responsible for this epidemic. We recommend that salmon be either cooked or frozen before it is eaten.