• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.7039-7043
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• 2013

A liver fluke, Opisthorchis viverrrini (OV), is the major cause of the high incidence of cholangiocarcinoma in North-eastern Thailand. The prevalence of OV infection remains high in various parts of the country, especially in wetland rural areas where a large proportion of the community work in agriculture and continue the traditional practice of eating raw or uncooked cyprinoid fish products. The national control program seems to have had little impact in many of these areas, and it has been difficult to make precise assessments of the overall effectiveness of the program. Therefore there is a need for a community-based approach to prevent infection with the parasite, ideally involving as many players as possible. Here we document an attempt to assess the best means to prevention on the basis of a community intervention in three villages in north-east Thailand, with participation of representatives of Health Promotion Hospitals of the Ministry of Public Health with dedicated staff, but also school teachers, independent government sponsored village health volunteers, and housewives responsible for cooking and diet selection. An action plan was followed, allowing detailed discussions of practical proposals, their introduction and then repeated reflection and further proposals at the individual village level.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.359-369
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• 2007

Amoebophrya is an obligate endoparasitic eukaryotic dinoflagellate infecting host species and eventually killing them within a short period. Because of its host specificity and significant impacts on population dynamics of host species, it has long been proposed to be a potential biological agent for controlling harmful algal bloom (HAB). For several decades, the difficulties of culturing host - parasite systems have been a great obstacle to further research on the biology of Amoebophrya but recent success of several culture systems reactivates this research field. In this study, as a preliminary work for understanding the impacts of Amoebophrya on the population dynamics of host species, semimonthly occurrence of infected host dinoflagellates by Amoebophrya spp. had been observed in Jinhae Bay for two years and with a host - parasite system cultivated, host specificity of Amoebophrya spp. on several dinoflagellates was tested. Amoebophrya spp. were observed in the cellular organelle and cytoplasm of several species including Akashiwo sanguinea, Ceratium fusus, Dinophysis acuminata, Heterocapsa triquetra, Oblea sp., Prorocentrum minimum, P. triestinum, Scrippsiella spinifera, and S. trochoidea. Among them two host - parasite systems for an athecate dinoflagellate, A. sanguinea, and for a thecate dinoflagellate, H. triquetra, had been able to be successfully established as laboratary cultures. Cross-infection tests for 6 species of dinoflagellates in which Amoebophrya was observed or had been reported to exist confirmed high preference for host species of the parasite. Through the continuous research on Amoebophrya occurring in Korean coastal waters, we need to maintain various host - parasite culture systems, which will be very helpful for understanding its ecological role in marine food webs and for applying the species to biologically control harmful algal blooms.

• Parasites, Hosts and Diseases
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• v.28 no.1
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• pp.31-38
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• 1990

Cryptosporidium, a coccidian parasite first described by Tyzzer (1907) from a laboratory mouse, has become an important human enteric pathogen causing overwhelming diarrhea especially in immunocompromised patients such as AIDS. This parasite has been reported from over 20 countries and is recognized as a cosmopolitan species. In Korea, however, thEre has been no report on human as well as animal cryptosporidiosis. This study was performed so as to verify the presence of Cryptosporidium in Korea by activating the parasite from laboratory mice by immunosuppression. Total 65 conventionally.bred ICR mice including a control (5 mice) and 3 experimental groups (20 each) were used for this study. Group I was immunosuppressed with Prednisolone injection (1 mg IM, every other day) for 7 weeks. Group II (prednisolone injection and tetracycline administration) and Group III. (prednisolone injection and trimethoprim-sulfamethoxazole administration) were prepared to observe the effect of antibacterial agents on the activation of cryptosporidiosis. In fecal examinations of mice Cryptosporidium oocysts($4-6{\mu\textrm{m}}$ in size) were detected from 1 week after the start of immunosuppression and the mice began to die. In H-E stained tissue sections of the lower jejunum, numerous very small ($2~4{\;}{\mu\textrm{m}}$), dense, ovoid or spherical, slightly basophilic bodies were seen attached on the free border of mucosal epithelial cells. In scanning and transmission electron microscopic observations, these organisms were identified as various developmental stages of Cryptosperidium. The species is considered to be C. parvum. Cryptosporidiosis was activated not only in Group I but also in Group II and III, indicating no protective effects of the antibacterial agents used, although the mice in Group II and III lived longer than those in Group I. The present study confirmed that Cryptosporidium exists in laboratory mice bred in Korea, and predicts possible occurrence of human cryptosporidiosis in Korea.

• ALGAE
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• v.22 no.4
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• pp.287-295
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• 2007

Infection of free-living dinoflagellates by endoparasitic dinoflagellates of the genus Amoebophrya are thought to have significant impacts on host population dynamics and have long been proposed to be a potential biological agent for controlling harmful algal bloom (HAB). To understand the impact of Amoebophrya on particular host species, however, it is necessary to quantify aspects the parasites life cycle. Here we used cultures of Amoebophryahost systems from Jinhae Bay, Korea to determine, parasite generation time, and dinospore survival and infectivity. The proportion of host cells infected by Amoebophrya sp. changed sharply from 5% to 87% with increasing dinospore:host inoculation ratios. In the absence of H. triquetra, most free-living dinospores died within 72 hours and their ability to infect host cells decreased remarkably in a day. The relatively short free-living phase of Amoebophrya suggests that the spread of infections is most likely to occur during seasons of high host abundance, as that is when dinospores have the greatest chance of encountering host cells. Infection of host cells inoculated with dinospores during the day was higher than when inoculated during the night, suggesting that infection rates might be related to environmental light conditions and/or diurnal biological rhythm of host species. Total generation times of parasite strains from a thecate dinoflagellate Heterocapsa triquetra were nearly the same regardless of dinospore:host inoculation ratios, representing 54 ± 0.5 h in a 1:1 ratio and 55 ± 1.2 h in a 20:1 ratio. Dinospore production of Amoebophrya sp. infecting Heterocapsa triquetra was estimated to be 125 dinospores per a strain of Amoebophrya sp. There is a growing need to maintain a variety of host-parasite systems in culture and to examine their autecology under various environmental conditions. Such studies would be very helpful in understanding ecological role of these parasites, their overlooked importance in the flow of material and energy in marine ecosystem, and their practical use as biological control agents applied directly to areas affected by HAB.

• Parasites, Hosts and Diseases
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• v.47 no.3
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• pp.275-280
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• 2009

Trichuris trichiura, commonly referred to as a whipworm, has a worldwide distribution, particularly among countries with warm, humid climates. In Korea, trichuriasis was a highly prevalent soil-transmitted helminthiasis until the 1970s. However, the nationwide prevalence decreased to 0.02% in 2004 as a result of national control activities and improvement in the socioeconomic status of Koreans. Most infected individuals have no distinct symptoms, if lightly infected. The diagnosis is typically confirmed by detection of T. trichiura eggs on examination of a stool sample; few reports have described detection of the parasite during colonoscopy. Recently, we managed 4 patients with trichuriasis who were diagnosed by detection of the parasite on colonoscopy, and we reviewed the literature on the colonoscopic diagnosis of T. trichiura in Korea. We suggest that colonoscopy might be a useful diagnostic tool, especially when infected by only a few male worms with no eggs in the stool.

• Parasites, Hosts and Diseases
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• v.31 no.3
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• pp.223-230
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• 1993

Monoclonal antibodies (Ub) against merozoites and sporozoites of the protozoan parasite Cryptosporidium pcnjum were examined for potential modulation of cryptosporidial infections in vivo by daily oral Ub administration to oocyst-inoculated neonatal mice. Monoclonal-treated neonatal mice were sacrified four and eight days post infection (pi) . Differences in infection rates were observed among the treatment groups at the p < 0.05 level. Suckling mice treated daily with orally administered mixtures of mAbs( ascitic fluids) showed significantly reduced parasite loads compared to control mice at flour and eight days pi, while suckling mice receiving mAb Cmg-3 alone showed signiacant differences only at 4 days Pi., suggesting that passive transfer of mAb may be of value in controlling cryptosporidial infections.

• Parasites, Hosts and Diseases
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• v.55 no.2
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• pp.159-165
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• 2017

Vivax malaria reemerged in Korea in 1993 and the outbreak has been continued with fluctuating numbers of annual indigenous cases. Understanding the nature of the genetic population of Plasmodium vivax circulating in Korea is beneficial for the knowledge of the nationwide parasite heterogeneity and in the implementation of malaria control programs in the country. Previously, we analyzed polymorphic nature of merozoite surface protein-1 (MSP-1) and MSP-$3{\alpha}$ in Korean P. vivax population and identified the Korean P. vivax population has been diversifying rapidly, with the appearance of parasites with new genetic subtypes, despite the recent reduction of the disease incidence. In the present study, we developed simple PCR-RFLP methods for rapid subtyping of MSP-1 and MSP-$3{\alpha}$ of Korean P. vivax isolates. These PCR-RFLP methods were able to easily distinguish each subtype of Korean P. vivax MSP-1 and MSP-$3{\alpha}$ with high accuracy. The PCR-RFLP subtyping methods developed here would be easily applied to massive epidemiological studies for molecular surveillance to understand genetic population of P. vivax and to supervise the genetic variation of the parasite circulating in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.4
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• pp.555-561
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• 1994

This paper presents results from a study of the body composition and sensory characteristics of female weaner goat meat. A completely randomized $3{\times}3{\times}2$ factorial design was used. Factors were genotype (Thai native; TN, 75% TN $\times$ 25% Anglo-Nubian; AN and 50% TN $\times$ 50% AN), feeding {grazing only, low (1.0% BW/d) and high (1.5% BW/d) concentrate supplementation and parasite control (undrenched and drenched)}. It was shown that there was no effect of genotype on body components and dressing percentage. However, TN and 75% TN $\times$ 25% AN kids had significantly (p<0.05) higher muscle to bone ratios (4.20% and 4.20%, respectively) compared with 50% TN $\times$ 50% AN kids (3.88%). Kids on grazing only had significantly (p<0.01) higher muscle percentage (64.12%) than did kids in low (61.30%) and high (60.62%) supplementary feeding program, but there was no significant (p>0.05) difference between low and high supplementary feeding groups. Kids offered supplementary feeding had significantly (p<0.01) higher percentages of total fat, intermuscular fat, pelvic fat and kidney fat than those of grazing only. Kids offered supplementary feeding had significantly (p<0.05) higher muscle to bone ratios and significantly (p<0.01) higher muscle plus fat to bone ratios compared with those of grazing only. This may be due to significantly lower (p<0.01) bone contents (14.95, 14.17 and 16.8% for kids offered low and high supplementary feeding and grazing only, respectively. There was no significant difference in sensory characteristics of goat meat between genotypes or feeding groups.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.9
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• pp.1389-1396
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• 2007

Twelve swamp buffaloes and Brahman cattle heifers (6 animals each) were randomly assigned to two treatments, control (grazing only) and supplementation of cassava hay (CH) at 1-kg dry matter per head per day (DM/hd/d), in a $2{\times}2$ factorial arrangement according to a cross-over design. The cassava hay contained a high level of protein (19.5% of DM) and a strategic amount of condensed tannins (4.0% of DM). As a result it was revealed that supplementation of CH at 1-kg DM/hd/d significantly (p<0.05) improved the nutrition of both swamp buffaloes and Brahman cattle in terms of DM, organic matter (OM), protein and energy intake and digestibility, ruminal NH3-N and rumen ecology. Supplementation significantly (p<0.05) reduced weight losses in both species and improved the health, in terms of reduced number of parasite eggs in feces (p<0.05), of both buffaloes and cattle. There tended to be a difference in term of response to CH between the two species. The DM, OM, protein intake and digestibility and total digestible energy intake tended to be higher for buffaloes as compared to cattle. Moreover, the percentage reduction of parasite eggs tended to be higher for buffaloes as compared to cattle (57.6 and 45.0%, respectively). However, there were no significant interactions between species and treatments.

• Parasites, Hosts and Diseases
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• v.48 no.4
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• pp.291-295
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• 2010

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. In this work, Pf-subtilisin-like protease 2 (Pf-Sub2) 5' untranslated region (UTR) was analyzed and its transcriptional activity was estimated by luciferase expression. Fourteen TATA boxes were observed but only one Oct-1 and c-Myb were done. In addition, host HGF interaction with Pf-Sub2 was evaluated by co-transfection of HGF- and Pf-Sub2-cloned vector. Interestingly, -1,422/+12 UTR exhibited the strongest luciferase activity but -329 to + 12 UTR did not exhibit luciferase activity. Moreover, as compared with the control of unexpressed HGF, the HGF protein suppressed luciferase expression driven by the 5' untranslated region of the Pf-Sub2 promoter. Taken together, it is suggested that HGF controls and interacts with the promoter region of the Pf-Sub2 gene.