Identity of Diphyllobothrium spp. (Cestoda: Diphyllobothriidae) from sea lions and people along the Pacific coast of South America.

Host specificity evidently is not expressed by various species of Diphyllobothrium that occur typically in marine mammals, and people become infected occasionally when dietary customs favor ingestion of plerocercoids. This report mainly concerns 2 species, Diphyllobothrium pacificum and Diphyllobothrium arctocephalinum, for which sea lions (Otariidae) are final hosts. The taxonomic status of those cestodes has not been clearly discernible because of misinterpretation of relationships; complex synonymies have resulted from misidentification(s). Stiles and Hassall in 1899 obtained, but did not describe, cestodes from the northern fur seal (Otariidae; Pribilof Islands). That taxon was subsequently studied by several investigators, with diverse conclusions. The valid designation is D. pacificum (Nybelin, 1931). In 1937, Johnston and Drummond described separately 2 conspecific cestodes from sea lions near Australia, designated D. arctocephalinum and Diphyllobothrium arctocephali. Both names have been listed incorrectly as synonyms of D. pacificum.

Population dynamics of the philometrid nematode Margolisianum bulbosum in the southern flounder Paralichthys lethostigma (Pisces: Paralichthyidae) in South Carolina, USA.

This is the first report of the philometrid nematode Margolisianum bulbosum Blaylock and Overstreet, 1999 from the southern flounder Paralichthys lethostigma on the east coast of the USA. Observation of adult female worms was used as an indication of the parasite's presence in the fish. Adult females were found only in P. lethostigma >50 mm total length. The overall prevalence was 74%, with a mean intensity of 5 female nematodes per parasitized fish. Infected flounders were found throughout the year with a statistically significant decrease in intensity in the winter months. Neither salinity, water temperature, fish gender nor fish age were found to influence either prevalence or intensity of infection in the flounder. While larvigerous (gravid) females were found throughout the year, the significant decrease in their occurrence during the summer through fall, in concert with an observed decrease in intensity of infection during the winter, indicated that the life cycle of this philometrid species is likely to be annual.

Survival of Anisakis simplex in arrowtooth flounder (Atheresthes stomia) during frozen storage.

Survival of naturally occurring larvae of Anisakis simplex in fresh arrowtooth flounder (Atheresthes stomia) was determined after storage for specified periods at four freezing temperatures. All larvae were killed by 96, 60, 12, and 9 h at temperatures of -15, -20, -30, and -40 degrees C, respectively. The average percentages of live larvae per fillet at the next shortest holding time were as follows: 72 h at -15 degrees C, 0 to 3%; 48 h at -20 degrees C, 11 to 30%; 9 h at -30 degrees C, 5%; and 6 h at -40 degrees C, 0 to 3%. Larval survival was directly related to fillet thickness or weight (P < or = 0.05). Larval death was directly correlated to freezing temperatures. Holding time necessary to kill larval nematodes decreased as storage temperature decreased.

Anisakid Parasites, Staphylococcus aureus and Bacillus cereus in Sushi and Sashimi from Seattle Area Restaurants.

Samples of salmon, tuna, mackerel, and rockfish sushi were analyzed for parasites from 32 of the approximately 50 restaurants in the Seattle area that prepare sushi. The restaurants were sampled up to three times over a 19-month period. Some specialty grocery stores providing restaurants and consumers with sashimi were also sampled. Salmon sushi was most commonly affected with almost 10% of pieces infected with a maximum of 3 nematodes per piece. Only single infections were present in mackerel sushi with frequency of 5%; and tuna and rockfish sushi were free of nematodes. All nematodes were third-stage juveniles of the genus Atiisakis . Except for two moribund nematodes, all juveniles from sushi were dead, most likely the result of the practice of using fish that have been previously frozen. The two moribund nematodes were present in one salmon sushi sample, indicating that incompletely frozen product had been used. For the sashimi, no parasites were found in tuna; however, a live anisakid was found in one collection of rockfish sashimi. Efforts to detect anisakid nematodes with nondestructive methods were generally unsuccessful. Neither inspection per ultraviolet light nor by candling was effective for salmon sushi. Candling was also ineffective for mackerel but was useful for rockfish and appears to be appropriate for the analysis of tuna sushi. Results of analyses of rice from sushi samples from 19 of the restaurants indicated that the pH levels were at 4.6 or below, and no fecal coliforms were detected. Most of the aerobic plate counts were below log 6, with only 2 between log 6 and log 7. Bacillus cereus and Staphylococcus aureus were detected in rice from six restaurants each, but in no samples were these two organisms found together, and levels were well below those of public health importance.