Natural infections of Asian Taenia saginata metacestodes in the livers of Korean domestic pigs.

The Taenia species in East Asia, hitherto identified as Taenia saginata, has been recognized as differing from the classical descriptions of life cycles and was recently named Taenia saginata taiwanensis (tentatively until 1992). Major differences between T. saginata and the newly recognized Asian T. saginata are their intermediate hosts and the infected tissues. Asian T. saginata metacestodes are found in the livers of pigs rather than in the muscles of cattle. In this study, we observed the natural infection status of Asian T. saginata metacestodes in the livers of 25,358 pigs at an abattoir in Cheongju City, Korea, from 1989 to 1990. Total 256 livers (1.01%) were infected with 1-96 (mean 2.5 per capita) metacestodes. Most of the metacestodes, however, were either calcified (87.1%) or highly degenerated (12.9%). Living metacestodes were found in only 0.01% (3/25, 358) of the examined livers. And these were distributed randomly in each lobe of the livers. The liver of pigs in Korea was confirmed as an organ hosting the Asian T. saginata metacestode. But its epidemiological significance as a source of human infections should be properly evaluated because of the rarity of the living metacestodes.