A Case Study of Human Infection with Small-Size Strobilae of Diphyllobothriid Tapeworm Discharged from a Man in Okayama Prefecture, Japan
A rare case of human infection with small-size diphyllobothriid tapeworm found in Okayama Prefecture, Japan, is reported. The patient was a 27-year-old man living in Yakage-Cho, Oda-Gun in Okayama. On April 28th 1995, the patient had spontaneously discharged 5 fragmented strobilae (3 to 33 cm long) without scolex of 64 cm in total length and 2.3 mm in width. Then he brought the specimen to Tsutsui Clinic wrapped with toilet paper. The external appearance of the strobilae resembled to that of Diphyllobothrium parvus (Stephes, 1908) Faust, 1929 known as parvum type of D. latum, although there was definite difference in arrangement of testes, thickness of longitudinal muscle layer and size of eggs. The specimen of the present case was identified as Diphyllobothrium latum (Linnaeus, 1758) Luhe, 1910 by Rausch and Hilliard (1970) based on morphological characteristics of serial sections (transverse, sagittal and horizontal) of proglottides and the eggs. The patient had customarily been eating raw meat of freshwater salmon as well as marine fishes such as common-makerel, yellow-tail, sea bream and flatfish. The route of the infection of the present case is not clarified.
