• Parasites, Hosts and Diseases
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• v.30 no.4
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• pp.341-348
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• 1992

Because no reference on trombiculid mites (Acarina: Trombiculidae) in Cheju Island where tsutsugamushi disease is highly endemic had been available, studies on trombiculid mites in Cheju Island were implemented during the period of August 1991-Apil 1992, and the results obtained are summarized as follows: (1) The species and numbers of the field rodents collected were 143 Apodemus agrarius chejuensis (92.3%), 11 Crocidura lasiura (7. l%) and 1 Micromys minutus (0.6%) From total 12,075 chiggers harvested, 9 species of 4 genera in Trombiculidae were identified. (2) The predominant species through all seasons was 1. setum (43.3%), followed by 1. orientale (27.4%) and 1. scutellare (26.6%). However, in autumn when the most cases of tsutsugamushi disease occur, 1. scutellere was prominently predominant, having 79.8% of the collected chiggers. (3) Among 1,1421. scutellare examined for Rickettsia tsutsugpmushi by means of IFA test, 6 individuals were found positive showing 0.5% of infection rate. This is the first finding that 1. scutellere is the second vector species of tsutsugamushi disease in Korea. (4) Antibody positive rate of A. agrarius chejuensis sera were 31.2% (44/139), and 1 M. minutes serum was also found positive. The seropositive rates by season were not so significantly different. Key words: Tsutsugamushi disease, epidemiology, vector species, Cheju Island, Korea.

• Parasites, Hosts and Diseases
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• v.54 no.3
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• pp.253-259
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• 2016

In the era of (pre) elimination setting, the prevalence of malaria has been decreasing in most of the previously endemic areas. Therefore, effective cost- and time-saving validated pooling strategy is needed for detection of malaria in low transmission settings. In this study, optimal pooling numbers and lowest detection limit were assessed using known density samples prepared systematically, followed by genomic DNA extraction and nested PCR. Pooling strategy that composed of 10 samples in 1 pool, $20{\mu}l$ in 1 sample, was optimal, and the parasite density as low as $2p/{\mu}l$ for both falciparum and vivax infection was enough for detection of malaria. This pooling method showed effectiveness for handling of a huge number of samples in low transmission settings (<9% positive rate). The results indicated that pooling of the blood samples before DNA extraction followed by usual nested PCR is useful and effective for detection of malaria in screening of hidden cases in low-transmission settings.

• Parasites, Hosts and Diseases
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• v.51 no.4
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• pp.413-419
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• 2013

The mainstay therapy against leishmaniasis is still pentavalent antimonial drugs; however, the rate of antimony resistance is increasing in endemic regions such as Iran. Understanding the molecular basis of resistance to antimonials could be helpful to improve treatment strategies. This study aimed to recognize genes involved in antimony resistance of Leishmania tropica field isolates. Sensitive and resistant L. tropica parasites were isolated from anthroponotic cutaneous leishmaniasis patients and drug susceptibility of parasites to meglumine antimoniate (Glucantime$^{(R)}$) was confirmed using in vitro assay. Then, complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) and real-time reverse transcriptase-PCR (RT-PCR) approaches were utilized on mRNAs from resistant and sensitive L. tropica isolates. We identified 2 known genes, ubiquitin implicated in protein degradation and amino acid permease (AAP3) involved in arginine uptake. Also, we identified 1 gene encoding hypothetical protein. Real-time RT-PCR revealed a significant upregulation of ubiquitin (2.54-fold), and AAP3 (2.86-fold) (P<0.05) in resistant isolates compared to sensitive ones. Our results suggest that overexpression of ubiquitin and AAP3 could potentially implicated in natural antimony resistance.

• Journal of Preventive Medicine and Public Health
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• v.30 no.1 s.56
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• pp.17-29
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• 1997

To estimate the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection and to determine associated risk factors, a population-based seroepidemiologic study was carried out. In 1993, a health examination survey of the population was carried out in rural area known to have a high incidence of liver cancer. The study population were those who volunteered to participate in a health survey over 10 years of age. Examinees were interviewed by specially trained staffs. Sera from 1,033 study subjects were tested for hepatitis B surface antigen (HBsAg) by .everse passive hemagglutinin (RPHA) estimation and for hepatitis C virus antibody (anti-HCV) by 2nd generation passive hemagglutinin (PHA) estimation. The age and sex standardized prevalence of HBsAg was 6.3% which was similar to national average, but that of anti-HCV was 5.1% which was 4 to 5 times higher than that of blood donors or other health examinees in Korea. In a multivariate analysis, transfusion history, surgical operative history, and acupuncture history were not associated with HBsAg positivity. In contrast, acupuncture history (adjusted odds ratio[OR]=2.2 : 95% Confidence interval[CI] 1.0-4.7) and surgical operative history(adjusted OR=2.0 : 95% CI 1.0-4.1) were associated with anti-HCV positivity. The present study suggest that there is an highly endemic area of HCV infection in Korea and probably this endemicity is associated with a parenteral source of HCV infection other than blood transfusion.

• Journal of agricultural medicine and community health
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• v.14 no.1
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• pp.5-15
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• 1989

To compare the health status of rural and urban aged persons(over 65 years old) by an abnormality of a hematologic and some biochemical values as well as urinalysis and chest X-ray, following examinations were done on 8,756(male : 4,339: female 4,417) by hemoglobin, total cholesteol, GOT, and glucose, on 9,207(male: 4,467; female : 4.740) by urinalysis and on 9,148(male : 4,426: female : 4,722) by chest X-ray. The results are as follows: 1) The proportion of outlier of normal range of the GOT(over 40 unit) showed higher in rural aged persons(5.3%) than in urban aged(2.8%). There was no significant difference in both of urban and rual female, but the rural male(7.4 showed significantly higher than the urban male(3.9% ). 2) The proportion of abnormality of the total cholesterol value(over 260 mg/dl) was 7,0% in urban and 1.7% in rural aged persons. In the male, there was no significant difference in both urban(2.2%) and rural(1.4%), however the urban female(10.5%) showed significantly higher than the rural female(2.2%). 3) In the blood glucose level, the proportion of abnormality(over 120 mg/dl) showed 17.1% in urban and 19.3% in rural aged persons. The rural aged persons in both sexes(male : 18.1% : female : 20.7%) were relatively higher abnormality rates than those of the urban aged(male : 15. 3%: female : 18.4% ) respectively. 4) The proportion of abnormality of hemoglobin level(less than 12.0 g/dl in male: less than 11.0 g/dl in female) showed 7.1% in urban and 2.6%J in rural aged persons. The urban aged persons in both sexes(male : 8.3%: female 6.3%) were relatively higher abnormality rates than those of the rural aged(male : 3.0%: female : 2.2%) 5) In the urinalysis by urine stix(Korea Green Cross Co.), the positive rates of urine protein were 1.0% in urban and 0.5% in rural aged per-sons, and there was no any significant differences in both areas by sex. 6) The positive rates of urine glucose in urban aged persons(5.8'% : male : 7.3% : female : 4.7%). showed relatively higher than those of rural aged (3.4% : male : 3.9%: female : 2.8%). 7) The positive findings of pulmonary tuberculosis by indirect X-ray examination were observed in 7.7% of aged persons in both rural and urban areas respectively. However, the positive rates of male in both areas(urban : 12.8% ; rural : 10.0%) showed higher than those of female (urban 4.2% ; rural 5.0%).

• Korean Journal of Ichthyology
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• v.6 no.1
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• pp.28-38
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• 1994

The ichthyofauna was investigated in Tongbok Lake and its tributaries from October, 1992 to January, 1993. Twenty-nine species representing 23 genera and 10 families were collected. Twenty-eight species in 22 genera and 9 families were from the stream area, while sixtween species in 14 genera and 7 families were from the lake area. Among these 14 species were classified as endemic species in Korea. Dominent species in the stream area were Zacco temmincki(28.04%) and Z. platypus (16.76%), whereas the lake area was overwhelmingly dominated by Hypomesus olidus(55.22%) and Z. platypus(44.31%). In the stream area. species diversity indices, evenness indices and dominant indices were 1.056, 0.730 and 0.270, respectively. In the area, the indices for species diversity, evenness and dominance were 0.314, 0.261 and 0.739, and those of body weights were 0.361, 0.300 and 0.700, respectively.

• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.102-110
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• 1985

In order to determine the epidemiological pattern of the Paragonimus westermani, the infestation rates for the cercarial and metacer-carial larvae of digenetic trematodes in the snail and crayfish hosts, and the prevalence of Paragonimus westermani among the residents in the vicinity of the stream Namdae, Wyangpi, and Kwang, in the Ulchin county, Kyungpook Province were studied from March to October in 1984. The population density of the snails per square meter of the habitats ranged from 5 to 25, with an average of 15. Among the seven habitats, one, Ducheon, had snails infested with the cercariae of Paragonimus westermani, and the proportion of infested snails was very low, the average being 0.152 per thousand. Of six hundred and four crayfish examined, 113 or 18.7 per cent harboured the encysted larvae of Paragonimus westermani. A high infestation rate for the metacercariae in the crayfish was found in two habitats; 39.0 per cent in the Ducheon and 21. 6 per cent m the Sokwang. The prevalence of Paragonimus westermani among the residents in Ulchin county was relatively high, 25.8 per cent by the Paragonimus intradermal tests, and the difference in the rate of infection between males and females was found to be significant (t>2). The results obtained in this study indicate that endemic foci of Paragonimus westermani exist in Ulchin county and the prevalence of this lung fluke among the residents is relatively high.

• Parasites, Hosts and Diseases
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• v.55 no.2
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• pp.149-158
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• 2017

Variant surface antigens (VSAs) encoded by pir families are considered to be the key proteins used by many Plasmodium spp. to escape the host immune system by antigenic variation. This attribute of VSAs is a critical issue in the development of a novel vaccine. In this regard, a population genetic study of vir genes from Plasmodium vivax was performed in the Republic of Korea (ROK). Eighty-five venous blood samples and 4 of the vir genes, namely vir 27, vir 21, vir 12, and vir 4, were selected for study. The number of segregating sites (S), number of haplotypes (H), haplotype diversity (Hd), DNA diversity (${\pi}$ and ${\Theta}_w$), and Tajima's D test value were conducted. Phylogenetic trees of each gene were constructed. The vir 21 (S=143, H=22, Hd=0.827) was the most genetically diverse gene, and the vir 4 (S=6, H=4, Hd=0.556) was the opposite one. Tajima's D values for vir 27 (1.08530, P>0.1), vir 12 (2.89007, P<0.01), and vir 21 (0.40782, P>0.1) were positive, and that of vir 4 (-1.32162, P>0.1) was negative. All phylogenetic trees showed 2 clades with no particular branching according to the geographical differences and cluster. This study is the first survey on the vir genes in ROK, providing information on the genetic level. The sample sequences from vir 4 showed a clear difference to the Sal-1 reference gene sequence, whereas they were very similar to those from Indian isolates.

• Parasites, Hosts and Diseases
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• v.55 no.2
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• pp.167-174
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• 2017

China still has more than 30,000 patients of advanced schistosomiasis while new cases being reported consistently. D-dimer is a fibrin degradation product. As ascites being the dominating symptom in advanced schistosomiasis, the present study aimed to explore a prediction model of ascites with D-dimer and other clinical easy-achievable indicators. A case-control study nested in a prospective cohort was conducted in schistosomiasis-endemic area of southern China. A total of 291 patients of advanced schistosomiasis were first investigated in 2013 and further followed in 2014. Information on clinical history, physical examination, and abdominal ultrasonography, including the symptom of ascites was repeatedly collected. Result showed 44 patients having ascites. Most of the patients' ascites were confined in the kidney area with median area of $20mm^2$. The level of plasma D-dimer and pertinent liver function indicators were measured at the initial investigation in 2013. Compared with those without ascites, cases with ascites had significantly higher levels of D-dimer ($0.71{\pm}2.44{\mu}g/L$ vs $0.48{\pm}2.12{\mu}g/L$, P=0.005), as well ALB (44.5 vs 46.2, g/L) and Type IV collagen (50.04 vs $44.50{\mu}g/L$). Receiver operating characteristic curve analyses indicated a moderate predictive value of D-dimer by its own area under curve (AUC) of 0.64 (95% CI: 0.54-0.73) and the cutoff value as $0.81{\mu}g/L$. Dichotomized by the cutoff level, D-dimer along with other categorical variables generated a prediction model with AUC of 0.76 (95% CI: 0.68-0.89). Risks of patients with specific characteristics in the prediction model were summarized. Our study suggests that the plasma D-dimer level is a reliable predictor for incident ascites in advanced schistosomiasis japonica patients.

• The Journal of the Korean life insurance medical association
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• v.2 no.1
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• pp.34-36
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• 1985

Korea is an endemic area of chronic hepatitis in the world. Liver cirrhosis and liver cell carcinoma, presumed to be related to such chronic hepatitis, are the major causes of death in this country. The purpose of this study is disclosing the sources of chronic hepatitis in Korea establishing its histologic characteristics, disclosing the patterns of progression in chronic hepatitis, delineating its prognosis and finally speculating its etiology. The study group was composed of 183 patients with biopsy-proven acute icteric viral hepaticis, 32 patients with biopsy- proven anicteric hepatitis and 260 patients with biopsy- proven chronic hepatitis. These patients submitted to long-term follow-up by means of liver needle biopsy and/or clinicolaboratory evaluation. The period of follow-up ranged from two months to 18 years. The histological features of the initial biopsy specimens of chronic hepatitis permitted a division of the cases cases into the following five types: Type I. Persisting portal hepatitis : so called persisting hepatitis 43 Type II. Chronic inactive hepatitis with incomplete strand septal fibrosis. This type has thin fibrotic septation in addition to Type I with portal sclerosis 38 Type III. Chronic active periportal hepatitis(CAPH) : so called aggressive hepatitis, characterized by marked piecemeal necrosis. This type has been subdivided further into three groups: AB and C on the basis of histologic features. A CAPH without cirrhosis 15 B CAPH with cirrhosis 99 C CAPH with diffuse acinus type parenchymal nodules; characterized by rosette-forming micronodules 21 Type IV. Subacute hepatic necrosis; characterized by multilobular and/or bridging necrosis. 14 Type V. Persisting lobular hepatitis; characterized by spotty necrosis, which looks very similar to acute viral hepatitis. Such histologic changes should be persisted for more than six months 30 In Korea the main source of chronic hepatitis is the anicteric type. Of the chronic hepatitis observed in the hospital, Type IIIb was the most frequent in its incidence and occasionally exhibited development of hepatocellular carcinoma, but the mortality was highest in Type IIIc during the period of follow-up. Histologic characteristics of these five types suggest a spectrum of chronic hepatitis in Korea from an early and mild stage to advanced and fatal cirrhosis, which is occasionally associated with primary hepatic cell carcinoma. It seems that Type IV can be followed by flare-up of various stages of acute and chronic hepatitis with HBsAg and that many cases of liver cirrhosis prevalent in Korea occur through such an active process of Type IV. The etiology is not established, but in Korea it is mainly related to HBsAg.