| Won-Ja Lee | 10 Articles |
Objectives
Ebola and Marburg viruses (EBOVs and MARVs, respectively) are causative agents of severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. In 2014, there was a major Ebola outbreak in various countries in West Africa, including Guinea, Liberia, Republic of Sierra Leone, and Nigeria. EBOV and MARV are clinically difficult to diagnose and distinguish from other African epidemic diseases. Therefore, in this study, we aimed to develop a method for rapid identification of the virus to prevent the spread of infection. Methods We established a conventional one-step reverse transcription-polymerase chain reaction (RT-PCR) assay for these pathogens based on the Superscript Reverse Transcriptase-Platinum <i>Taq</i> polymerase enzyme mixture. All assays were thoroughly optimized using <i>in vitro</i>-transcribed RNA. Results We designed seven primer sets of nucleocapsid protein (NP) genes based on sequences from seven filoviruses, including five EBOVs and two MARVs. To evaluate the sensitivity of the RT-PCR assay for each filovirus, 10-fold serial dilutions of synthetic viral RNA transcripts of EBOV or MARV NP genes were used to assess detection limits of viral RNA copies. The potential for these primers to cross react with other filoviruses was also examined. The results showed that the primers were specific for individual genotype detection in the examined filoviruses. Conclusion The assay established in this study may facilitate rapid, reliable laboratory diagnosis in suspected cases of Ebola and Marburg hemorrhagic fevers. Citations
Citations to this article as recorded by
To compare the epidemiological characteristics of dengue cases imported by travelers or immigration in both Korea and Japan, we determined dengue incidence and related risk factors. During 2006–2010, 367 and 589 imported dengue cases were reported in Korea and Japan, respectively. In Korea, the presumptive origins for the dengue infections were Southeast Asia (82.6%), Southern Asia (13.9%), Eastern Asia (1.1%), South America (0.3%), Central America (0.3%), Africa (0.3%), and other countries (1.6%). In Japan, the origins of the infections were Southeast Asia (69.8%), Southern Asia (20.0%), Eastern Asia (1.7%), South America (2.5%), Central America (1.2%), Africa (1.2%), Oceania (2.4%), and other countries (1.2%). In both countries, more dengue cases were reported for men than for women (<i>p</i> < 0.01), and those aged 20–30 years accounted for > 60% of the total cases. The frequency of imported cases in summer and autumn (∼70% of total cases) was similar in both countries. This study demonstrates that there is a similar pattern of imported dengue cases in Korea and Japan. Therefore, there is a risk of an autochthonous dengue outbreak in Korea, as indicated by the recent outbreak in Japan in 2014.
Citations
Citations to this article as recorded by
Current Ebola virus outbreak in West Africa already reached the total number of 1,323 including 729 deaths by July 31st. the fatality is around 55% in the southeastern area of Guinea, Sierra Leone, Liberia, and Nigeria. The number of patients with Ebola Hemorrhagic Fever (EHF) was continuously increasing even though the any effective therapeutics or vaccines has not been developed yet. The Ebola virus in Guinea showed 98% homology with Zaire Ebola Virus.Study of the pathogenesis of Ebola virus infection and assess of the various candidates of vaccine have been tried for a long time, especially in United States and some European countries. Even though the attenuated live vaccine and DNA vaccine containing Ebola viral genes were tested and showed efficacy in chimpanzees, those candidates still need clinical tests requiring much longer time than the preclinical development to be approved for the practical treatment.It can be expected to eradicate Ebola virus by a safe and efficient vaccine development similar to the case of smallpox virus which was extinguished from the world by the variola vaccine.
Citations
Citations to this article as recorded by
Objectives
The purpose of this study was to verify the feasibility of using the glyceraldehyde-3-phosphate dehydrogenase (GAP) promotor based <i>Pichia pastoris</i> expression system to produce tick-borne encephalitis virus (TBEV) virus-like particles (VLPs). Methods The complementary DNA encoding the TBEV prM signal peptide, prM, and E proteins of TBEV Korean strain (KrM 93) was cloned into the plasmid vector pGAPZɑA, then integrated into the genome of <i>P. pastoris</i>, under the control of the GAP promoter. Expression of TBEV VLPs was determined by Western blotting using monoclonal antibody against TBEV envelope (E) protein. Results Recombinant TBEV VLPs consisting of prM and E protein were successfully expressed using the GAP promoter-based <i>P. pastoris</i> expression system. The results of Western blotting showed that the recombinant proteins were secreted into the culture supernatant from the <i>P. pastoris</i> and glycosylated. Conclusion This study suggests that recombinant TBEV VLPs from <i>P. pastoris</i> offer a promising approach to the production of VLPs for use as vaccines and diagnostic antigens. Citations
Citations to this article as recorded by
Objectives
Several different methods are currently used to detect antibodies to Japanese encephalitis virus (JEV) in serum samples or cerebrospinal fluid. These methods include the plaque reduction neutralization test (PRNT), the hemagglutination inhibition (HI) test, indirect immunofluorescence assay (IFA), and enzyme-linked immunosorbent assay (ELISA). The purpose of this study was to compare the performance of each method in detecting vaccine-induced antibodies to JEV. Methods The study included 29 children who had completed a primary immunization schedule with an inactivated vaccine against JEV derived from mouse brain (<i>n</i> = 15) or a live attenuated SA14-14-2 vaccine (<i>n</i> = 14). Serum samples were collected between 3 months and 47 months after the last immunization. The serum samples were tested by performing the PRNT, HI test, in-house IFA, and commercial ELISA. The antibody detection rates were compared between tests. Results All 29 serum samples were positive with the PRNT, showing antibody titers from 1:20 to 1:2560. The HI test showed positive rates of 86.7% (13/15) and 71.4% (10/14) in the inactivated and live attenuated vaccine groups, respectively. The results of the IFA for immunoglobulin (Ig)G were positive in 53.3% (8/15) of children in the inactivated vaccine group and 35.7% (5/14) in the live attenuated vaccine group. Neither the IFA nor ELISA detected JEV IgM antibodies in any of the 29 children. Conclusion These results show that detection rates of vaccine-induced antibodies to JEV have a wide range (0–100%) depending on the testing method as well as the time since immunization and individual differences between children. These findings are helpful in interpreting serological test results for the diagnosis of Japanese encephalitis in situations where vaccines are widely administered. Citations
Citations to this article as recorded by
Objectives
This study aims to develop a high-sensitivity antibody diagnostic kit that will enable a rapid and accurate detection of <i>Cryptospofidium parvum</i> and <i>Giardia lamblia</i> in patients with diarrhea. Methods The cultivated <i>C. parvum</i> oocysts and <i>G. lamblia</i> 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 <i>C. parvum</i> and <i>G.lamblia</i> 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 <i>Cryptosporidium parvum</i> and <i>Giardia lamblia</i> was 125 oocysts/mL and 1250 cysts/mL, respectively. In addition, during testing they did not show cross-reactivity to viruses (<i>n</i> = 15), bacteria (<i>n</i> =17), and parasites (<i>n</i> = 9). Conclusion The rapid diagnostic antibody kit developed in this study, which specifically responds to <i>C. parvum</i> and <i>G. lamblia</i>, will be useful in detecting and monitoring diarrheal infections. Citations
Citations to this article as recorded by
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 <i>Giardia lamblia</i> was detected in fecal samples of 7 people using the polymerase chain reaction method. Although <i>G. lamblia</i> 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 <i>G. lamblia</i>, but its precise cause has not been clarified. Conclusion This outbreak resulting from <i>G. lamblia</i> is very meaningful as the first outbreak of an infection by a water-borne parasite in Korea. Citations
Citations to this article as recorded by
Objectives
Vivax malaria has reemerged and become endemic in Korea. Our study aimed to analyze by both longitudinal and cross-sectional genetic diversity of this malaria based on the <i>P vivax Merozoite Surface Protein</i> (<i>PvMSP</i>) gene parasites recently found in the Korean peninsula. Methods <i>PvMSP-1</i> gene sequence analysis from <i>P vivax</i> isolates (n = 835) during the 1996-2010 period were longitudinally analyzed and the isolates from the Korean peninsula through South Korea, the demilitarized zone and North Korea collected in 2008-2010 were enrolled in an overall analysis of MSP-1 gene diversity. Results New recombinant subtypes and severe multiple-cloneinfection rates were observed in recent vivax parasites. Regional variation was also observed in the study sites. Conclusion This study revealed the great complexity of genetic variation and rapid dissemination of genes in <i>P vivax.</i> It also showed interesting patterns of diversity depending, on the region in the Korean Peninsula. Understanding the parasiteninsula. Under genetic variation may help to analyze trends and assess the extent of endemic malaria in Korea. Citations
Citations to this article as recorded by
Objectives
The prevalence of <i>Clonorchis sinensis</i> 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 <i>C. sinensis</i>, 255 (0.8%) for <i>Heterophyes</i> spp., 36 (0.1%) for <i>Echinostoma</i> spp., 30 (0.1%) for <i>Trichuris trichiura</i>, 8 (0.03%) for <i>Ascaris lumbricoides</i>, 7 (0.02%) for <i>Gymnophalloide seoi</i>, and 50 (0.02%) for <i>Trichostrongylus orientalis</i>. Number of residents harbouring protozoan cysts in the faeces was 133 (1.3%) for <i>Entamoeba</i> spp. and 50 (0.2%) for <i>Giardia lamblia.</i> The positive rates of <i>C. sinensis</i> 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 <i>C. sinensis</i> 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 <i>C. sinensis</i> compared with the result of southern endemic areas of Korea in 2006. Citations
Citations to this article as recorded by
|
|
