A Survey of Intestinal Parasite Infection during a 10-Year Period (2003-2012)

Abstract

Background: Due to a reduction in the number of parasite infections, attention paid to the importance of intestinal parasites has decreased. However, intestinal parasite infections remain ubiquitous and have reappeared as a growing problem in recent decades due to changing lifestyles such as increased overseas travel. In this study, we evaluated trends in intestinal parasite infection using stool examination in a single institute. Methods: From January 2003 to December 2012, we reviewed all stool examination results performed at Samsung Medical Center. Fecal examinations were performed by formalin-ether sedimentation. Results: A total 429,866 stool examinations were performed resulting in 14,672 cases with positive findings of helminth eggs or protozoan cysts, of which the positive rate was 3.41% on average. The annual positive rate decreased from 5.68% in 2003 to 2.43% in 2012. The positive rate of intestinal parasites, excepting Endolimax nana and Entamoeba coli, was 1.52% on average. Positive rates decreased from 2.13% to 1.10% for helminth egg detections and from 2.55% to 1.30% for protozoan cyst detections during the same time period. Among nematodes, Trichuris tricuria was the most common and had an increasing positive rate after 2010. Clonorchis sinensis was the most prevalent trematode parasite, with an annual average of 528 cases. Conclusion: Infection rates of intestinal parasites have decreased over the last 10 years. However, Trichuris tricuria has reappeared and has become a major contributor to parasite infections. Further education and control efforts are needed for greater prevention and eventual eradication of parasitic infections. (Ann Clin Microbiol 2013;16:134-139)