Abstract
Objective: From the annual changes in the positive rate for parasitological examinations at Center for Multiphasic Health Testing and Services, Mitsui Memorial Hospital, we determined whether continuing parasitological examinations in Ningen Dock would be valuable or not.
Methods: Four thousand six hundred and seventy three subjects who underwent a two-day Ningen Dock at our Center between August 1994 and March 2012 were enrolled. Parasitological examinations were performed on fecal specimens from the subjects by the formalin-ether sedimentation technique.
Results: Of the total of 4,673 parasitological examinations that were carried out, 219 were positive for parasitic worms. The mean positive rate was 4.7%. The positive rate in parasitological examinations rapidly increased, from 2.6% in 1994 to 21.1% in 1999, and then it fell to 5.2% in 2000. After 2000, the trend was flat, with an average of 3.7%. As for the breakdown of the detected parasites, excepting overlap subjects, there were 150 cases of Metagonimus yokogawai, 12 cases of Giardia lamblia, 2 cases of Entamoeba coli, and one case each of Clonorchis sinensis, Trichuris trichiura, and Cyclospora cayetanensis. The results of 8 requests for parasitic body identification were Anisakis spp in 7 cases and Ascaris lumbricoides in 1 case.
Conclusions: Parasites were continuously detected at our center, with a mean rate of 2-3% per year from 2005 onwards and subjects without symptoms were found to have Giardia lamblia category Ⅴ infection. These findings suggest that it will be valuable to continue parasitological examinations in Ningen Dock in the future. Also in consideration of the fact that there will be an increasing number of the elderly among examinees as time goes on, they will be important for preventing opportunistic infections.
