Volume 97, Issue 3
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



We conducted this study to explore the extent of occult helminth infection identified by fecal parasitological examinations or organ-specific examinations such as colonoscopy and abdominal ultrasonography (US) during health checkups. We analyzed 197,422 fecal samples from 99,451 subjects who received health checkups at a single center over 10 years. We found that 3,472 (1.8%) samples from 3,342 (3.4%) subjects tested positive for parasitic ova, including clonorchiasis, metagonimiasis, trichuriasis, ascariasis, trichostrongylosis, taeniasis, and enterobiasis. The detection rate for clonorchiasis was higher in those who were taking their first examination than in those who had been examined previously. The detection rate for clonorchiasis decreased gradually over the 10 years. Only 2.5% of the patients with clonorchiasis showed US or computed tomography (CT) images that were compatible with the disease. Clonorchiasis patients who had abdominal US or CT images that suggested clonorchiasis were older and had lower body mass indices and higher eosinophil counts than did those whose US or CT images did not suggest the disease. We observed worms in 9% of the patients with trichuriasis who had received a colonoscopy. Colonoscopy also uncovered adult worms in 0.03% of subjects who were not identified as having ova in their fecal helminth examinations. In summary, our study shows that occult helminth infection is fairly frequently identified by a variety of methods during health checkups, which suggests that doctors need to make greater effort to identify and treat occult helminth infections in Korea.


Article metrics loading...

The graphs shown below represent data from March 2017
Loading full text...

Full text loading...



  1. Sinniah B, Hassan AK, Sabaridah I, Soe MM, Ibrahim Z, Ali O, , 2014. Prevalence of intestinal parasitic infections among communities living in different habitats and its comparison with one hundred and one studies conducted over the past 42 years (1970 to 2013) in Malaysia. Trop Biomed 31: 190206. [Google Scholar]
  2. Kim TS, .; Working Groups in National Institute of H, Korea Association of Health Promotion, 2009. A nationwide survey on the prevalence of intestinal parasitic infections in the Republic of Korea, 2004. Korean J Parasitol 47: 3747. [Google Scholar]
  3. Bouvard V, .; Group WHOIAfRoCMW, 2009. A review of human carcinogens–Part B: biological agents. Lancet Oncol 10: 321322. [Google Scholar]
  4. Lim MK, ., 2006. Clonorchis sinensis infection and increasing risk of cholangiocarcinoma in the Republic of Korea. Am J Trop Med Hyg 75: 9396. [Google Scholar]
  5. Hong ST, Fang Y, , 2012. Clonorchis sinensis and clonorchiasis, an update. Parasitol Int 61: 1724. [Google Scholar]
  6. Garborg K, Holme O, Loberg M, Kalager M, Adami HO, Bretthauer M, , 2013. Current status of screening for colorectal cancer. Ann Oncol 24: 19631972. [Google Scholar]
  7. Del Vecchio Blanco G, Paoluzi OA, Sileri P, Rossi P, Sica G, Pallone F, , 2015. Familial colorectal cancer screening: when and what to do? World J Gastroenterol 21: 79447953. [Google Scholar]
  8. Hong ST, Choi MH, Kim CH, Chung BS, Ji Z, , 2003. The Kato-Katz method is reliable for diagnosis of Clonorchis sinensis infection. Diagn Microbiol Infect Dis 47: 345347. [Google Scholar]
  9. Ok KS, Kim YS, Song JH, Lee JH, Ryu SH, Lee JH, Moon JS, Whang DH, Lee HK, , 2009. Trichuris trichiura infection diagnosed by colonoscopy: case reports and review of literature. Korean J Parasitol 47: 275280. [Google Scholar]
  10. Lee C, Yang JI, Byun HJ, Kang JM, Choi S, Yim JY, , 2013. Status of primary liver cancer found through routine health check-up. J Korean Med Sci 28: 14491453. [Google Scholar]
  11. Choi D, Hong ST, , 2007. Imaging diagnosis of clonorchiasis. Korean J Parasitol 45: 7785. [Google Scholar]
  12. Lim JH, Mairiang E, Ahn GH, , 2008. Biliary parasitic diseases including clonorchiasis, opisthorchiasis and fascioliasis. Abdom Imaging 33: 157165. [Google Scholar]
  13. Xia J, Jiang SC, Peng HJ, , 2015. Association between liver fluke infection and hepatobiliary pathological changes: a systematic review and meta-analysis. PLoS One 10: e0132673. [Google Scholar]
  14. Hong ST, Yoon K, Lee M, Seo M, Choi MH, Sim JS, Choi BI, Yun CK, Lee SH, , 1998. Control of clonorchiasis by repeated praziquantel treatment and low diagnostic efficacy of sonography. Korean J Parasitol 36: 249254. [Google Scholar]
  15. Nutman TB, , 2007. Evaluation and differential diagnosis of marked, persistent eosinophilia. Immunol Allergy Clin North Am 27: 529549. [Google Scholar]
  16. Chang CW, Chang WH, Shih SC, Wang TE, Lin SC, Bair MJ, , 2008. Accidental diagnosis of Trichuris trichiura by colonoscopy. Gastrointest Endosc 68: 154. [Google Scholar]
  17. Wang DD, Wang XL, Wang XL, Wang S, An CL, , 2013. Trichuriasis diagnosed by colonoscopy: case report and review of the literature spanning 22 years in mainland China. Int J Infect Dis 17: e1073e1075. [Google Scholar]
  18. Do KR, Cho YS, Kim HK, Hwang BH, Shin EJ, Jeong HB, Kim SS, Chae HS, Choi MG, , 2010. Intestinal helminthic infections diagnosed by colonoscopy in a regional hospital during 2001–2008. Korean J Parasitol 48: 7578. [Google Scholar]
  19. Oh JK, Lim MK, Yun EH, Cho H, Park EY, Choi MH, Shin HR, Hong ST, , 2014. Control of clonorchiasis in Korea: effectiveness of health education for community leaders and individuals in an endemic area. Trop Med Int Health 19: 10961104. [Google Scholar]
  20. O’Connell EM, Nutman TB, , 2015. Eosinophilia in infectious diseases. Immunol Allergy Clin North Am 35: 493522. [Google Scholar]
  21. Chai JY, Darwin Murrell K, Lymbery AJ, , 2005. Fish-borne parasitic zoonoses: status and issues. Int J Parasitol 35: 12331254. [Google Scholar]
  22. Jeong YI, Shin HE, Lee SE, Cheun HI, Ju JW, Kim JY, Park MY, Cho SH, , 2016. Prevalence of Clonorchis sinensis infection among residents along 5 major rivers in the Republic of Korea. Korean J Parasitol 54: 215219. [Google Scholar]
  23. Steinmann P, Yap P, Utzinger J, Du ZW, Jiang JY, Chen R, Wu FW, Chen JX, Zhou H, Zhou XN, , 2015. Control of soil-transmitted helminthiasis in Yunnan province, People’s Republic of China: experiences and lessons from a 5-year multi-intervention trial. Acta Trop 141: 271280. [Google Scholar]
  24. Ziegelbauer K, Speich B, Mausezahl D, Bos R, Keiser J, Utzinger J, , 2012. Effect of sanitation on soil-transmitted helminth infection: systematic review and meta-analysis. PLoS Med 9: e1001162. [Google Scholar]
  25. Hong ST, Chai JY, Choi MH, Huh S, Rim HJ, Lee SH, , 2006. A successful experience of soil-transmitted helminth control in the Republic of Korea. Korean J Parasitol 44: 177185. [Google Scholar]
  26. Jeandron A, Abdyldaieva G, Usubalieva J, Ensink JH, Cox J, Matthys B, Rinaldi L, Cringoli G, Utzinger J, , 2010. Accuracy of the Kato-Katz, adhesive tape and FLOTAC techniques for helminth diagnosis among children in Kyrgyzstan. Acta Trop 116: 185192. [Google Scholar]

Data & Media loading...

  • Received : 06 Feb 2017
  • Accepted : 30 May 2017
  • Published online : 24 Jul 2017

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error