The present study was undertaken to know the infection status of Cryptosporidium parvum among the residents of Chorwon-gun, Kangwon-do in 1993. Total 461 fecal samples were collected from the inhabitants residing in Chorwon-gun during the period of August 12 to September 14, 1993. Fecal smears were prepared by formalin-ether sedimentation, and examined after modified acid fast staining. Of the 461 fecal samples, 9 (1.9%) were positive for C. parvum oocysts. The positive cases were limited to thirties (4) patients, forties (3), and sixties (2), and no oocyst was detected in other age groups. The oocyst positive rate for male was 1.4% and that of female was 2.6%.
Adolescent ; Adult ; Age Factors ; Aged ; Animals ; Child ; Cryptosporidiosis/epidemiology ; Cryptosporidiosis/parasitology ; Cryptosporidium parvum/isolation & purification ; Feces/parasitology ; Female ; Human ; Korea/epidemiology ; Male ; Middle Aged ; Parasite Egg Count ; Sex Factors

Arthropod antigens are main causative agents which induce allergic responses in humans. However, little information is known about the prevalence of specific arthropod allergens in Koreans with allergic diseases. The current study was designed to determine the positive rates of arthropod antibodies by the Korean inhalant panel of MAST-CLA. One hundred sixty patients, who were diagnosed with allergic rhinitis from an out-patient center at the Soonchunhyang University Chunan Hospital, were studied between August 1998 to July 2000. The overall positive rate, at least more than one specific antibody of arthropods such as Dermatophagoides farinae (Df), Dermatophagoides pteronyssinus (Dp), and cockroach mix (Cm), was 46.9%. Each positive rate of Df, Dp, and Cm was 45.0%, 43.1%, and 8.8%, respectively. A significant agreement among arthropod allergens was observed (Df and Dp: 95.6%, Kappa = 0.911, P < 0.001). Our data supported the fact that arthropods were the most common allergens in Korean patients with allergic rhinitis; however, the MAST-CLA should be modified to increase specificity of arthropod allergens.
Adolescent ; Adult ; Allergens/immunology ; Animals ; Antibodies/analysis ; Arthropods/immunology ; Child ; Female ; Human ; Korea/epidemiology ; Male ; Prevalence ; Rhinitis, Allergic, Perennial/epidemiology ; Rhinitis, Allergic, Perennial/immunology ; Support, Non-U.S. Gov't

We report a case of gastric pseudoterranoviasis proven by gastrofiberscopy on Dec. 13, 1994. The 34-year-old male patient, residing in Chungju-shi, was admitted to Konkuk University Hospital complaining of prickling epigastric pain. The symptoms suddenly attacked him two days after eating raw marine fish at Chonan-shi. By the gastrofiberscopic examination, a long white-yellowish nematode was found from the fundus region of stomach. The worm was 34.50 x 0.84 mm in size, and was identified as a 3rd stage larva of Pseudoterranova decipiens judging from the position of the intestinal cecum. This is the 12th confirmed case of human pseudoterranoviasis in Korea.
Adult ; Animals ; Anisakiasis/parasitology ; Ascaridoidea/isolation & purification ; Gastric Mucosa/parasitology ; Gastroscopy ; Human ; Korea ; Larva ; Male ; Stomach Diseases/parasitology

To evaluate the factors that determine the transmission level of vivax malaria using vectorial capacity, entomological surveys were conducted from June to August, 2000. From 6 nights of human-bait collection in Paju, the human biting rate (ma) was counted as 87.5 bites/man/night. The parity of Anopheles sinensis from human baiting collections fluctuated from 41% to 71% (average 48.8%) of which the rate gradually increased as time passed on: 35.2% in Jun.; 55.0% in July; 66.2% in Aug. From this proportion of parous, we could estimate the probability of daily survival rate of An. sinensis to be 0.79 assumed with 3 days gonotrophic cycle and the expectancy of infective life through 11 days could be defined as 0.073. Blood meal analysis was performed using ELISA to determine the blood meal source. Only 0.8% of blood meals were from human hosts. We could conclude that An. sinensis is highly zoophilic (cow 61.8%). Malaria is highly unstable (stability index < 0.5) in this area. From these data, vectorial capacity (VC) was determined to be 0.081. In spite of a high human biting rate (ma), malaria transmission potential is very low due to a low human blood index. Therefore, we could conclude that malaria transmission by An. sinensis is resulted by high population density, not by high transmission potential. For this reason, we need more effort to decrease vector population and vector-human contact to eradicate malaria in Korea.
Animals ; Anopheles/parasitology ; Human ; Insect Vectors ; Korea ; Malaria, Vivax/parasitology ; Malaria, Vivax/transmission ; Parity ; Plasmodium vivax/pathogenicity ; Plasmodium vivax/physiology ; Population Density

The objectives of the present study were to (1) determine the susceptibility of Anopheles sinensis to Korean isolates of Plasmodium vivax, (2) establish a method to collect large quantities of P. vivax sporozoites for use as antigen in seroepidemiological studies, and (3) investigate the characteristics of Korean isolates of P. vivax sporozoites. Females of Anopheles sinensis were collected at non-epidemic area, Seokwha-ri, Cheongwon-gun and Chungcheongbuk-do using tent-trap methods coupled with dry ice. The females were artificially infected with gametocytes of P. vivax using blood obtained from P. vivax malaria patients. Individual mosquitoes were infected using either a parafilm-covered glass feeding apparatus or were allowed to feed on naturally infected volunteers. Mosquitoes were sacrificed between 16 and 18 days post-feeding and an enzyme-linked immunosorbent assay (ELISA) was used to detect sporozoites. Four (33.4%) of 12 mosquitoes, which were fed on naturally infected volunteers directly, were positive for sporozoites. In cases, the mosquitoes allowed to feed on whole blood which were extract from three different patients with heparin treated vacuutainers using a parafilm-covered glass apparatus. Two of 55 (3.6%) were positive which blood sample was maintained at room temperature for 8 hours, 1 of 68 (1.5%) was positive which blood was maintained at 4 degrees C for 24 hours and 1 of 47 (2.3%) was positive at 4 degrees C for 48 hours. The mean number of sporozoites was estimated about 818 (n = 8; range of 648-1,056) based on optical density values of ELISA.
Animals ; Anopheles/parasitology ; Enzyme-Linked Immunosorbent Assay ; Human ; Korea ; Plasmodium vivax/isolation & purification ; Plasmodium vivax/pathogenicity ; Support, Non-U.S. Gov't

Western blot analysis was performed to diagnose vivax malaria using stage-specific recombinant antigens. Genomic DNA from the whole blood of a malaria patient was used as templates to amplify the coding regions for the antigenic domains of circumsporozoite protein (CSP-1), merozoite surface protein (MSP-1), apical merozoite antigen (AMA-1), serine repeat antigen (SERA), and exported antigen (EXP-1) of Plasmodium vivax. Each amplified DNA fragment was inserted into a pGEX-4T plasmid to induce the expression of GST fusion protein in Escherichia coli by IPTG. The bacterial cell extracts were separated on 10% SDS-PAGE followed by western blot analysis with patient sera which was confirmed by blood smear examination. When applied with patient sera, 147 (91.9%) out of 160 vivax malaria, 12 (92.3%) out of 13 falciparum malaria, and all 9 vivax/falciparum mixed malaria reacted with at least one antigen, while no reactions occurred with 20 normal uninfected sera. In the case of vivax malaria, CSP-1 reacted with 128 (80.0%) sera, MSP-1 with 102 (63.8%), AMA-1 with 128 (80.0%), SERA with 115 (71.9%), and EXP-1 with 89 (55.6%), respectively. We obtained higher detection rates when using 5 antigens (91.9%) rather than using each antigen solely (55.6-80%), a combination of 2 (76.3-87.5%), 3 (85.6-90.6%), or 4 antigens (89.4-91.3%). This method can be applied to serological diagnosis, mass screening in endemic regions, or safety test in transfusion of prevalent vivax malaria.
Animals ; Antigens, Protozoan/blood ; Biological Markers/blood ; Blotting, Western ; Human ; Life Cycle Stages/immunology ; Malaria, Vivax/diagnosis ; Mass Screening ; Plasmodium vivax/immunology ; Recombinant Proteins/blood ; Serologic Tests/methods ; Support, Non-U.S. Gov't

We conducted both the small subunit ribosomal DNA (SSU rDNA) polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and mitochondrial (mt) DNA RFLP analyses for a genetic characterization of Acanthamoeba isolates from contact lens storage cases of students in Seoul, Korea. Twenty-three strains of Acanthamoeba from the American Type Culture Collection and twelve clinical isolates from Korean patients were used as reference strains. Thirty-nine isolates from contact lens storage cases were classified into seven types (KA/LS1, KA/LS2, KA/LS4, KA/LS5, KA/LS7, KA/LS18, KA/LS31). Four types (KA/LS1, KA/LS2, KA/LS5, KA/LS18) including 33 isolates were regarded as A. castellanii complex by riboprints. KA/LS1 type was the most predominant (51.3%) in the present survey area, followed by KA/LS2 (20.9%), and KA/LS5 (7.7%) types. Amoebae of KA/LS1 type had the same mtDNA RFLP and riboprint patterns as KA/E2 and KA/E12 strains, clinical isolates from Korean keratitis patients. Amoebae of KA/LS2 type had the identical mtDNA RFLP patterns with A. castellanii Ma strain, a corneal isolate from an American patient as amoebae of KA/LS5 type, with KA/E3 and KA/E8 strains from other Korean keratitis patients. Amoebae of KA/LS18 type had identical patterns with JAC/E1, an ocular isolate from a Japanese patient. Three types, which remain unidentified at species level, were not corresponded with any clinical isolate in their mtDNA RFLP and riboprint patterns. Out of 39 isolates analyzed in this study, mtDNA RFLP and riboprint patterns of 33 isolates (84.6%) were identical to already known clinical isolates, and therefore, they may be regarded as potentially keratopathogenic. These results suggest that contact lens wearers in Seoul should pay more attention to hygienic maintenance of contact lens storage cases for the prevention of Acanthamoeba keratitis.
Acanthamoeba/classification ; Acanthamoeba/genetics ; Acanthamoeba/isolation & purification ; Acanthamoeba Keratitis/parasitology ; Acanthamoeba Keratitis/prevention & control ; Animals ; Contact Lenses/parasitology ; DNA, Mitochondrial/genetics ; DNA, Protozoan/genetics ; Human ; Korea ; Students

Randomly selected 435 clones from Acanthamoeba healyi cDNA library were sequenced and a total of 387 expressed sequence tags (ESTs) had been generated. Based on the results of BLAST search, 130 clones (34.4%) were identified as the genes encoding surface proteins, enzymes for DNA, energy production or other metabolism, kinases and phosphatases, protease, proteins for signal transduction, structural and cytoskeletal proteins, cell cycle related proteins, transcription factors, transcription and translational machineries, and transporter proteins. Most of the genes (88.5%) are newly identified in the genus Acanthamoeba. Although 15 clones matched the genes of Acanthamoeba located in the public databases, twelve clones were actin gene which was the most frequently expressed gene in this study. These ESTs of Acanthamoeba would give valuable information to study the organism as a model system for biological investigations such as cytoskeleton or cell movement, signal transduction, transcriptional and translational regulations. These results would also provide clues to elucidate factors for pathogenesis in human granulomatous amoebic encephalitis or keratitis by Acanthamoeba.
Acanthamoeba/cytology ; Acanthamoeba/genetics ; Acanthamoeba/pathogenicity ; Amebiasis/parasitology ; Animals ; DNA, Protozoan/genetics ; Expressed Sequence Tags ; Gene Library ; Human ; Protozoan Proteins/genetics ; Sequence Analysis, DNA ; Signal Transduction ; Support, Non-U.S. Gov't

The present study was designed to investigate polymorphism in Duffy binding protein (DBP) gene of Plasmodium vivax isolates of Korea. Thirty samples were obtained from P. vivax patients in Yonchon-gun, Kyonggi-do in 1998. The PCR products of the samples were subjected to sequencing and hybridization analyses of the regions II and IV of P. vivax DBP gene. Two genotypes, SK-1 and SK-2, were identified on the basis of amino acid substitution and deletion. The genotype of 10 isolates was SK-1 and that of 20 isolates was SK-2. Most of the predicted amino acids in the region II of DBP gene were conserved between the Korean isolates and Belem strain except for 4-5 amino acid substitutions. In the region IV of DBP, a 6-bp insert that was shown in the Sal-1 allele type was found in SK-1, and a 27-bp insert that was shown in the Papua New Guinea allele type was found in SK-2. In conclusion, the present findings suggest that two genotypes of P. vivax coexist in the endemic area of Korea.
Amino Acid Sequence ; Animals ; Antigens, Protozoan ; Base Sequence ; Carrier Proteins/analysis ; Carrier Proteins/chemistry ; Carrier Proteins/genetics ; DNA, Protozoan/genetics ; Genotype ; Human ; Korea ; Malaria, Vivax/parasitology ; Molecular Sequence Data ; Plasmodium vivax/genetics ; Plasmodium vivax/isolation & purification ; Polymerase Chain Reaction ; Polymorphism (Genetics) ; Protozoan Proteins ; Receptors, Cell Surface/analysis ; Receptors, Cell Surface/chemistry ; Receptors, Cell Surface/genetics ; Support, Non-U.S. Gov't

A cDNA of 1.1 kb comprising the gene encoding the peroxiredoxin of Toxoplasma gondii (TgPrx) has been cloned. The open reading frame of 591 bp was translated into a protein of 196 amino acids with a molecular mass of 25 kDa. Conserved 2 cysteine domains of Phe-Val-Cys-Pro and Glu-Val-Cys-Pro indicated TgPrx belonged to 2-Cys Prx families. TgPrx showed the highest homology with that of Arabidopsis thaliana by 53.9% followed by Entamoeba histolytica with 39.5% by the amino acid sequence alignment. Polyclonal antibody against recombinant TgPrx detected 25 kDa band in T. gondii without binding to host cell proteins. TgPrx was located in the cytoplasm of T. gondii extracellularly or intracellularly by immunofluorescence assay. The expression of TgPrx was increased as early as 30 min after the treatment with artemisinin in the intracellular stage, while no changes in those of host Prx I and TgSOD. This result implies that TgPrx may function as an antioxidant protecting the cell from the attack of reactive oxygen intermediates. It is also suggested that TgPrx is a possible target of chemotherapy.
Amino Acid Sequence ; Animals ; Antioxidants ; Artemisinins ; Base Sequence ; Cloning, Molecular ; Cysteine/metabolism ; Molecular Sequence Data ; Nucleic Acid Amplification Techniques ; Peroxidases/chemistry ; Peroxidases/genetics ; Peroxidases/physiology ; Sesquiterpenes/pharmacology ; Support, Non-U.S. Gov't ; Toxoplasma/enzymology