Osong Public Health and Research Perspectives

Hyeng-Il Cheun

3 Articles

Development of a Diagnostic Kit to Detect Cryptosporidium parvum and Giardia lamblia: Hyeng-Il Cheun, Byung-Suk Chung, Da-Won Ma, Bo-La Goo, Shin-Hyeong Cho, Mi-jung Ji, Won-Ja Lee; Osong Public Health Res Perspect. 2013;4(3):146-151. Published online June 30, 2013; DOI: https://doi.org/10.1016/j.phrp.2013.04.006

Abstract PDF: Objectives
This study aims to develop a high-sensitivity antibody diagnostic kit that will enable a rapid and accurate detection of Cryptospofidium parvum and Giardia lamblia in patients with diarrhea.
Methods
The cultivated C. parvum oocysts and G. lamblia cysts in each calf and dog were injected to mice to obtain antibodies, which were titrated. Spleen cells of the immunized mouse were separated and blended with myelomas to produce hybrid cell lines that form monoclonal antibodies. Using ELISA method, antibodies that specifically respond to C. parvum and G.lamblia were then selected. The cells were injected into the abdominal cavity of a BALB/c mouse to isolate hydrops abdominis containing high level of antibodies. The IgG antibody was purified using protein G gel.
Results
The detection limit of monoclonal antibodies for Cryptosporidium parvum and Giardia lamblia was 125 oocysts/mL and 1250 cysts/mL, respectively. In addition, during testing they did not show cross-reactivity to viruses (n = 15), bacteria (n =17), and parasites (n = 9).
Conclusion
The rapid diagnostic antibody kit developed in this study, which specifically responds to C. parvum and G. lamblia, will be useful in detecting and monitoring diarrheal infections.

The First Outbreak of Giardiasis with Drinking Water in Korea: Hyeng-Il Cheun, Cheon-Hyeon Kim, Shin-Hyeong Cho, Da-Won Ma, Bo-La Goo, Mun-Su Na, Seung-Ki Youn, Won-Ja Lee; Osong Public Health Res Perspect. 2013;4(2):89-92. Published online April 30, 2013; DOI: https://doi.org/10.1016/j.phrp.2013.03.003

Abstract PDF: Objectives
To identify the pathogen of the diarrhea outbreak in a village in Jeollabuk province in Korea in April 2010.
Methods
DNA extraction was performed from the 120 L of collected water, which was centrifuged at 10,000 x g for 30 min. PCR reactions were conducted in a total of 25 ul, which included PCR premix (GenDEPOT, Barker, TX, USA), 2 ul (∼100 ng) of extracted DNA, and 10 pmol of each primer.
Results
Nine people out of 25 had a symptom of abdominal pain accompanied by diarrhea after they used stored valley water in a water tank as a provisional water supply source without chlorine sterilization. Among them Giardia lamblia was detected in fecal samples of 7 people using the polymerase chain reaction method. Although G. lamblia was also detected from water provided by the provisional water supply system stored in the water tank and used as drinking water, it was not detected in the water tank itself. This water-borne outbreak is considered to have occurred when the provisional water supply tube was destroyed under a building construction and contaminated by G. lamblia, but its precise cause has not been clarified.
Conclusion
This outbreak resulting from G. lamblia is very meaningful as the first outbreak of an infection by a water-borne parasite in Korea.

Prevalence of Clonorchis sinensis Infections Along the Five Major Rivers in Republic of Korea, 2007: Hyun-Kyung Kim, Hyeng-Il Cheun, Byung-Suk Cheun, Ki-Yeon Lee, Tong-Soo Kim, Sang-Eun Lee, Won-ja Lee, Shin-Hyeong Cho; Osong Public Health Res Perspect. 2010;1(1):43-49. Published online December 31, 2010; DOI: https://doi.org/10.1016/j.phrp.2010.12.010

Abstract PDF: Objectives
The prevalence of Clonorchis sinensis infection was investigated among residents of the five major river basins, that is, Hangang, Nakdonggang, Seomjingang, Yeongsangang, and Geumgang River basins in Korea.
Methods
From January to December 2007, a total of 31,268 stool samples were collected from 29 localities and examined by the formalin-ether sedimentation technique.
Results
Intestinal parasite eggs and/or protozoan cysts were detected from 2957 (9.5%) inhabitants. Number of residents harbouring helminth eggs in the faeces was 2542 (8.1%) for C. sinensis, 255 (0.8%) for Heterophyes spp., 36 (0.1%) for Echinostoma spp., 30 (0.1%) for Trichuris trichiura, 8 (0.03%) for Ascaris lumbricoides, 7 (0.02%) for Gymnophalloide seoi, and 50 (0.02%) for Trichostrongylus orientalis. Number of residents harbouring protozoan cysts in the faeces was 133 (1.3%) for Entamoeba spp. and 50 (0.2%) for Giardia lamblia. The positive rates of C. sinensis in Nakdonggang, Seomjingang, Yeongsangang, Geumgang, and Hangang River basins were 12.2%, 9.5%, 3.3%, 3.0%, and 1.0%, respectively. The egg positive rate of C. sinensis was higher in male (10.6%) than in female (6.1%), and the age group of 50s had the highest positive rate (10.4%).
Conclusion
The result of this study revealed little decrease in positive rate of C. sinensis compared with the result of southern endemic areas of Korea in 2006.

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