Publications by authors named "Pyo Yun Cho"

Acanthamoeba keratitis (AK) is an infectious ocular disease which is difficult to diagnose correctly and cure. Development of an effective and safe therapeutic drug for AK is needed. Our preliminary screening of more than 200 extracts from wild plants collected in Korea suggested the potential amoebicidal activity of (Cav.

View Article and Find Full Text PDF
Article Synopsis
  • Clonorchiasis, caused by the parasite Clonorchis sinensis, affects around 15 million people predominantly in East Asia.
  • Researchers expressed 607 proteins to identify potential antigens for diagnosing the infection, ultimately selecting 18 candidates based on how they reacted with infected human sera.
  • Among the tested proteins, CsAg17 showed the best performance with a sensitivity of 77.1% and specificity of 71.2%, making it a promising option for quick diagnostic tests for clonorchiasis.
View Article and Find Full Text PDF

Malaria remains one of the leading health burdens in the developing world, especially in several sub-Saharan Africa countries; and Uganda has some of the highest recorded measures of malaria transmission intensity in the world. It is evident that the prevalence of malaria infection, the incidence of disease, and mortality from severe malaria remain very high in Uganda. Although the recent stable political and economic situation in the last few decades in Uganda supported for a fairly good appreciation of malaria control, the declines in infection, morbidity, and mortality are not sufficient to interrupt transmission and this country is among the top 4 countries with cases of malaria, especially among children under 5 years of age.

View Article and Find Full Text PDF
Article Synopsis
  • Waterborne parasitic protozoa are major causes of diarrhea globally, often found in drinking water and recreational areas like pools and lakes.
  • A three-year study monitored oocysts and cysts in surface water from lakes, rivers, and water plants, examining 50 water samples, revealing contamination across all sites.
  • The study found 22% of samples contained oocysts and 32% had cysts, highlighting the need for monitoring protocols that consider changing contamination patterns over time and space.
View Article and Find Full Text PDF

Background: Accurate diagnosis of Plasmodium infection is crucial for prompt malaria treatment and surveillance. Microscopic examination has been widely applied as the gold standard for malaria diagnosis in most part of malaria endemic areas, but its diagnostic value has been questioned, particularly in submicroscopic malaria. In this study, the diagnostic performance of microscopic examination and nested polymerase chain reaction (PCR) was evaluated to establish optimal malaria diagnosis method in Myanmar.

View Article and Find Full Text PDF

The vivax malaria epidemic has persisted in South Korea since its reemergence in 1993. Although there has been a significant decrease in the number of malaria cases in recent years, vivax malaria is still a major public health concern. To gain in-depth insight into the genetic makeup of Korean Plasmodium vivax, we analyzed polymorphic patterns of two major antigens, merozoite surface protein-1 (MSP-1) and MSP-3α, in 255 Korean P.

View Article and Find Full Text PDF

Background: Plasmodium vivax apical membrane antigen-1 (PvAMA-1) is a leading candidate antigen for blood stage malaria vaccine. However, antigenic variation is a major obstacle in the development of an effective vaccine based on this antigen. In this study, the genetic structure and the effect of natural selection of PvAMA-1 among Korean P.

View Article and Find Full Text PDF

A complementary DNA (cDNA) encoding a glucose transporter of Clonorchis sinensis (CsGLUT) was isolated from the adult C. sinensis cDNA library. The open reading frame of CsGLUT cDNA consists of 1653 base pairs that encode a 550-amino acid residue protein.

View Article and Find Full Text PDF

Background: The bacteria Orientia tsutsugamushi is the causative agent of scrub typhus, mite-borne disease, which causes an acute febrile illness in patients. An epidemiologic study was conducted to understand the characteristics of scrub typhus in South Korea.

Findings: Reporting of tsutsugamushi disease is mandatory in South Korea since 1994.

View Article and Find Full Text PDF

In recent years, rapid diagnostic tests (RDTs) have been widely used for malaria detection, primarily because of their simple operation, fast results, and straightforward interpretation. The Asan EasyTest™ Malaria Pf/Pan Ag is one of the most commonly used malaria RDTs in several countries, including Korea and India. In this study, we tested the diagnostic performance of this RDT in Uganda to evaluate its usefulness for field diagnosis of malaria in this country.

View Article and Find Full Text PDF

To evaluate the seroprevalence against circumsporozoite protein (CSP) of Plasmodium vivax in sera of Korean patients, the central repeating domain (CRD) of CSP was cloned and analyzed. From the genomic DNA of patient's blood, 2 kinds of CSPs were identified to belong to a VK210 type, which is the dominant repeating of GDRA(D/A)GQPA, and named as PvCSPA and PvCSPB. Recombinantly expressed his-tagged PvCSPA or PvCSPB in Escherichia coli reacted well against sera of patients in western blot, with the detecting rate of 47.

View Article and Find Full Text PDF

Background: The merozoite surface protein-3β of Plasmodium vivax (PvMSP-3β) is one of the candidate antigens for blood stage malaria vaccine development. The polymorphisms in PvMSP-3β have been reported in certain P. vivax isolates.

View Article and Find Full Text PDF
Article Synopsis
  • * A total of 1,774 blood samples revealed an overall seroprevalence of 0.94%, with the highest rates in Paju-si (1.9%) and a gradual decrease in annual parasite incidence from 1.69 to 0.80 over the studied years.
  • * The findings suggest that antibody levels, particularly in Gimpo-si, correlate strongly with annual parasite incidence, highlighting the importance of seroprevalence data for understanding malaria
View Article and Find Full Text PDF

Background: Plasmodium vivax re-emerged in 1993. Although the number of infections has been steadily decreasing, it is likely to continue to affect public health until it is eradicated. The aim of this study is to measure anti-circumsporozoite protein (CSP) antibody and compare malaria prevalence.

View Article and Find Full Text PDF

The voltage-gated Ca(2+) channel β-subunit is a member of the membrane-associated guanylate kinase family and modulates kinetic properties of the Ca(2+) channels, such as their voltage-dependent activation and inactivation rates. Two cDNA clones were identified to encode each β-subunit isotype of the voltage-gated Ca(2+) channel of Clonorchis sinensis, CsCavβ1 and CsCavβ2, which consist of 606 and 887 amino acids, respectively. CsCavβ1 was found to be similar to the β-subunit containing two conserved serine residues that constitute the consensus protein kinase C phosphorylation site in the β-interaction domain (BID).

View Article and Find Full Text PDF

Microscopic examination of eggs of parasitic helminths in stool samples has been the most widely used classical diagnostic method for infections, but tiny and low numbers of eggs in stool samples often hamper diagnosis of helminthic infections with classical microscopic examination. Moreover, it is also difficult to differentiate parasite eggs by the classical method, if they have similar morphological characteristics. In this study, we developed a rapid and sensitive polymerase chain reaction (PCR)-based molecular diagnostic method for detection of Clonorchis sinensis eggs in stool samples.

View Article and Find Full Text PDF

Background: Transmission-blocking vaccines (TBVs), which target the sexual stages of malaria parasites to interfere with and/or inhibit the parasite's development within mosquitoes, have been regarded as promising targets for disrupting the malaria transmission cycle. In this study, genetic diversity of four TBV candidate antigens, Pvs25, Pvs28, Pvs48/45, and PvWARP, among Plasmodium vivax Korean isolates was analysed.

Methods: A total of 86 P.

View Article and Find Full Text PDF

Rapid in-field diagnosis is very important to prevent the outbreak of various infectious and contagious diseases. Highly sensitive and quantitative detection of diseases can be performed using fluorescent immunochemical assay with specific antigen-antibody binding and a good quality fluorophore. This can lead to the development of a small, portable, quantitative biosensor to transmit diagnostic results to a control center in order to systematically prevent disease outbreaks.

View Article and Find Full Text PDF

Plasmodium vivax Duffy binding protein (PvDBP) is a micronemal type I membrane protein that plays an essential role in erythrocyte invasion of merozoites. PvDBP is a prime blood stage vaccine candidate antigen against P. vivax, but its polymorphic nature represents a major obstacle to the successful design of a protective vaccine against vivax malaria.

View Article and Find Full Text PDF

The seroepidemiological status of toxoplasmosis was surveyed among the residents of Cheorwon-gun, Gangwon-do by means of ELISA using a crude extract antigen of Toxoplasma gondii. The sera of 1,661 adult residents (866 males and 795 females) were collected and checked for IgG antibody titers, which showed 17.0% positive rate (282 sera).

View Article and Find Full Text PDF

Seroepidemiological changes of Toxoplasma gondii infection among the residents of the islands of Gangwha-gun, Incheon for 2 years were surveyed and evaluated by ELISA using a crude extract antigen. In 2010, sera of 919 adult residents in Gyodong-myeon and 313 adults in Samsan-myeon were collected and checked for IgG antibody titers, which showed 14.5% (133 sera) and 19.

View Article and Find Full Text PDF

The onset, severity, and ultimate outcome of malaria infection are influenced by parasite-expressed virulence factors as well as by individual host responses to these determinants. In both humans and mice, liver injury follows parasite entry, persisting to the erythrocytic stage in the case of infection with the fatal strain of Plasmodium falciparum. Hepatic nuclear factor (HNF)-1α is a master regulator of not only the liver damage and adaptive responses but also diverse metabolic functions.

View Article and Find Full Text PDF

Clonorchis sinensis is the causative agent of the life-threatening disease endemic to China, Korea, and Vietnam. It is estimated that about 15 million people are infected with this fluke. C.

View Article and Find Full Text PDF

The onset, severity, and ultimate outcome of malaria infection are influenced by parasite-expressed virulence factors and individual host responses to these determinants. In both humans and mice, liver injury is involved after parasite entry, which persists until the erythrocyte stage after infection with the fatal strain Plasmodium falciparum (Pf). Hepatocyte growth factor (HGF) has strong anti-apoptotic effects in various kinds of cells, and also has diverse metabolic functions.

View Article and Find Full Text PDF

Antigenic proteins from Clonorchis sinensis have been previously purified and evaluated for their antigenicity to enable the serodiagnosis of clonorchiasis. Though they were of high specificity, molecularly defined proteins were reported to be less sensitive as single antigens than crude antigen. To resolve this issue, 11 clones were selected by immunoscreening an adult C.

View Article and Find Full Text PDF