Genotypes of Blastocystis sp. among elderly health checkup people in South Korea with a questionnaire on risk factors

Taehee Chang, Bong Kwang Jung, Hyejoo Shin, Sooji Hong, Seungwan Ryoo, Jeonggyu Lee, Seihee Han, Sun Min Park, Min Suk Rhee, Heejin Kimm, Sun Ha Jee, Jong Yil Chai

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Blastocystis sp. is a common zoonotic intestinal parasite of humans and animals, and has been classified into at least 17 distinct subtypes. Despite its potential impact on public health, the prevalence and subtype distribution of Blastocystis sp. have seldom been the study subject in South Korea. To determine the prevalence and subtype distribution of Blastocystis sp. and to obtain information on risk factors, we performed a cross-sectional study targeting elderly health checkup people, who visited Seoul Western Branch of the Korea Association of Health Promotion (KAHP) in October 2019. Stool samples were collected from 293 participants consisting of 128 males and 165 females with a mean age of 64.7 years (from 50 to 88 years) with a questionnaire on potential risk factors. All the samples were tested by PCR targeting the SSU rRNA gene of Blastocystis sp., and nucleotide sequences of positive samples were used to identify the subtypes. The overall prevalence of Blastocystis sp. was 9.2% (27/293). Among the positive samples, subtype 3 was predominant (59%; 16/27), followed by subtype 1 (41%; 11/27). No other subtypes were detected. In the univariable analysis, the age, sex, presence of digestive symptoms, source of drinking water, and history of drug intake were not significantly associated with Blastocystis sp. infection. Two parameters, including the Enterococcus hirae bacterial infection and the frequency of intake of cooked or boiled vegetables less than twice a week, showed statistical significance. However, the multivariable regression analysis revealed that only the latter parameter was statistically significant. The results suggested that subtypes 3 and 1 are the 2 major genotypes of Blastocystis sp. among elderly people in South Korea, and low frequency of consuming cooked or boiled vegetables is a potential risk factor.

Original languageEnglish
Pages (from-to)3297-3306
Number of pages10
JournalParasitology Research
Issue number9
Publication statusPublished - 2021 Sept

Bibliographical note

Funding Information:
The authors thank the staff of the Seoul Western Branch, Korea Association of Health Promotion, Seoul, South Korea, who helped with sample collection. We also appreciate the staff in the Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, South Korea, who helped with molecular analysis of Enterococcus spp.

Funding Information:
This study was supported by a grant from the Ministry of Food and Drug Safety, the Republic of Korea, in 2017–2019 (17162MFDS034).

Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.


  • Blastocystis sp
  • Molecular subtyping
  • Risk factor
  • South Korea

ASJC Scopus subject areas

  • Parasitology
  • General Veterinary
  • Insect Science
  • Infectious Diseases


Dive into the research topics of 'Genotypes of Blastocystis sp. among elderly health checkup people in South Korea with a questionnaire on risk factors'. Together they form a unique fingerprint.

Cite this