• Journal of Environmental Health Sciences
• /
• v.28 no.5
• /
• pp.102-105
• /
• 2002

The gills of seven black rockfish, Sebastes melanops collected from Hatfield Marine Science Center Aquarium during September 19-October 3,2001 were examined for parasites attached to the gills. The species of Sebastes melanops were Microcotyle sebastis baled on the number of clamps and testes. The prevalence of 42.9％ was recorded for host and fourteen worms of three black rockfish were recovered. Mean intensity of infection of Microcotyle sebastis individuals per infected host for black rockfish was 2.0(range 1-11). Monogenea helminth sites were mainly consist of second and third gill arch's filaments of black rockfish. The results revealed that surface area of the 2nd and 3rd pair of gills might affect the distribution of Microcotyle sebastis.

• BMB Reports
• /
• v.49 no.11
• /
• pp.590-597
• /
• 2016

Parasitic diseases remain an unarguable public health problem worldwide. Liver fluke Clonorchis sinensis is a high risk pathogenic parasitic helminth which is endemic predominantly in Asian countries, including Korea, China, Taiwan, Vietnam, and the far eastern parts of Russia, and is still actively transmitted. According to the earlier $8^{th}$ National Survey on the Prevalence of Intestinal Parasitic Infections in 2012, C. sinensis was revealed as the parasite with highest prevalence of 1.86% in general population among all parasite species surveyed in Korea. This fluke is now classified under one of the definite Group 1 human biological agents (carcinogens) by International Agency of Research on Cancer (IARC) along with two other parasites, Opisthorchis viverrini and Schistosoma haematobium. C. sinensis infestation is mainly linked to liver and biliary disorders, especially cholangiocarcinoma (CCA). For the purposes of this mini-review, we will only focus on C. sinensis and review pathogenesis and carcinogenesis of clonorchiasis, disease condition by C. sinensis infestation, and association between C. sinensis infestation and CCA. In this presentation, we briefly consider the current scientific status for progression of CCA by heavy C. sinensis infestation from the food-borne trematode and development of CCA.

• Journal of fish pathology
• /
• v.10 no.2
• /
• pp.137-142
• /
• 1997

A monogenean gill parasite, Prosomicrocotyla gotoi, and a digenean intestinal fluke. Opecoelus sphaericus, were found from greenilngs (Hexagrammos otakii) captured at the Korean southern sea. P. gotoi was characterized by having two separated frills of opisthaptor and distinguished from P. chirii in testis and clamp numbers. O. sphaericus had three pairs of finger-like marginal appendages on the ventral sucker and the parasite was distinguished from O. nipponicus in the location pattern of testes. These two helminth species were the first recording species in Korea.

• Parasites, Hosts and Diseases
• /
• v.43 no.4 s.136
• /
• pp.141-147
• /
• 2005

A practical and convenient method of rearing Eucyclops serrulatus in a microculture environment is described. A complete life cycle of E. serrulatus was maintained in a narrow space on a microscope slide glass on which a cover glass of $22{\times}40mm$ in size was mounted at a height of 0.8mm. The culture medium was constituted by bottled mineral water boiled with grains of Glycine max (soybean). Chilomonas paramecium, a free-living protozoan organism, was provided as live food. Growth of nauplii hatched from eggs to the first stage of copepodite took an average of 7.7 days, and the growth of copepodite 1 to the egg-bearing adult female took an average of 20.1 days in the microculture cell with an average life time of 44.7 days. Continuous passage of cope pods was successfully maintained as long as sufficient medium and food were provided. The microculture method enables an in situ microscopic observation on the growth and developmental process of helminth larvae experimentally infected to copepods as well as of copepod itself. Furthermore, it does not require anesthetization and, therefore, minimize the amount of stress exposed to cope pods during the handling process.

• Parasites, Hosts and Diseases
• /
• v.52 no.5
• /
• pp.569-573
• /
• 2014

In a paleo-parasitological analysis of soil samples obtained from V-shaped pits dating to the ancient Baekje period in Korean history, we discovered Ascaris lumbricoides, Trichuris trichiura, and Clonorchis sinensis eggs. In light of the samples' seriously contaminated state, the V-shaped pits might have served as toilets, cesspits, or dung heaps. For a long period of time, researchers scouring archaeological sites in Korea have had difficulties locating such structures. In this context then, the present report is unique because similar kind of the ancient ruins must become an ideal resource for successful sampling in our forthcoming paleoparasitological studies.

• Parasites, Hosts and Diseases
• /
• v.51 no.6
• /
• pp.663-667
• /
• 2013

Free-grazing ducks play a major role in the rural economy of Eastern Asia in the form of egg and meat production. In Thailand, the geographical location, tropical climate conditions and wetland areas of the country are suitable for their husbandry. These environmental factors also favor growth, multiplication, development, survival, and spread of duck parasites. In this study, a total of 90 free-grazing ducks from northern, central, and northeastern regions of Thailand were examined for intestinal helminth parasites, with special emphasis on zoonotic echinostomes. Of these, 51 (56.7%) were infected by one or more species of zoonotic echinostomes, Echinostoma revolutum, Echinoparyphium recurvatum, and Hypoderaeum conoideum. Echinostomes found were identified using morphological criteria when possible. ITS2 sequences were used to identify juvenile and incomplete worms. The prevalence of infection was relatively high in each region, namely, north, central, and northeast region was 63.2%, 54.5%, and 55.3%, respectively. The intensity of infection ranged up to 49 worms/infected duck. Free-grazing ducks clearly play an important role in the life cycle maintenance, spread, and transmission of these medically important echinostomes in Thailand.

• Parasites, Hosts and Diseases
• /
• v.46 no.1
• /
• pp.1-15
• /
• 2008

Introduction of double-stranded RNA (dsRNA) into some cells or organisms results in degradation of its homologous mRNA, a process called RNA interference (RNAi). The dsRNAs are processed into short interfering RNAs (siRNAs) that subsequently bind to the RNA-induced silencing complex (RISC), causing degradation of target mRNAs. Because of this sequence-specific ability to silence target genes, RNAi has been extensively used to study gene functions and has the potential to control disease pathogens or vectors. With this promise of RNAi to control pathogens and vectors, this paper reviews the current status of RNAi in protozoans, animal parasitic helminths and disease-transmitting vectors, such as insects. Many pathogens and vectors cause severe parasitic diseases in tropical regions and it is difficult to control once the host has been invaded. Intracellularly, RNAi can be highly effective in impeding parasitic development and proliferation within the host. To fully realize its potential as a means to control tropical diseases, appropriate delivery methods for RNAi should be developed, and possible off-target effects should be minimized for specific gene suppression. RNAi can also be utilized to reduce vector competence to interfere with disease transmission, as genes critical for pathogenesis of tropical diseases are knockdowned via RNAi.

• Parasites, Hosts and Diseases
• /
• v.22 no.2
• /
• pp.215-222
• /
• 1984

During February 1982 to September 1983, a total of 105 domestic ducks (Anas platyrhynchos var. domestica Linnaeus) were collected from Ichon Gun, Pusan City, Chunchon City, Yanggu Gun, Taejeon City and unknown areas in Korea. In the results, six trematode and one nematode species of helminth parasites were obtained and described as follows: Amphimerus anatis Yamaguti, 1933, Echinostoma miyagawai Ishii, 1932, Echinochasmus japonicus Tanabe, 1926, Cryptocotyle sp., Notocotylus attenuatus (Rudolphi, 1809) Kossack, 1911, Apatemon sp. and nematode species, Heterakis gallinarum Schrank, 1788. From this collection, Amphimerus anatis Yamaguti, 1933, Echinochasmus japonicus Tanabe, 1926, genus Cryptocotyle Liihe, 1899 and genus Apatemon Szidat, 1928 were firstly recorded in Korea.

• Parasites, Hosts and Diseases
• /
• v.24 no.2
• /
• pp.209-212
• /
• 1986

The present study was undertaken to evaluate the present status of intestinal parasitic infection in Seoul area, Korea. During the period from June 1985 to July 1986, a total of 5,251 stool samples were collected in Department of Clinical Pathology, Hanyang University Hospital and examined by formalin-ether sedimentation technique once for helminth ova and protozoan cysts. The results were summarized as follows: 1. The overall egg positive rate of intestinal helminthes was 2.53%; and 1.43% for Clonorchis sinensis, 0.7% for Trichuris trichiura, 0.13% for Metagonimus yokogawai, 0.06% for hookworm, and 0.02% for Ascaris lumbricoides, Diphyllobothrium latum and Hymenolepis nana, respectively. 2. The overall cyst positive rate of intestinal protozoa was 1.07%. Cyst positive rate was 0.06% for Entamoeba histolytica and 0.13% for Giardia lamblia, respectively. 3. Higher prevalence of intestinal parasitic infection was observed in male and in $21{\sim}50$ year-old groups. 4. The highest prevalence of Clonorchis sinensis infection was observed in 40th age group (3.4%), and male (2.3%) was more infected than female (0.7%) in general.

• Parasites, Hosts and Diseases
• /
• v.55 no.5
• /
• pp.569-573
• /
• 2017

The present study was performed to reveal the current status and risk factors of Strongyloides stercoralis infections in the villages of Kenethao district, Xayaburi Province, Lao PDR. Fecal specimens were collected and examined for S. stercoralis using Koga-agar plate culture technique. Among 516 individuals, the prevalence of S. stercoralis and hookworm infection was 44.2% and 17.1%, respectively. Co-infection was detected in 13.2% of the cases. The prevalence did not significantly differ between males and females (P=0.193). However, the prevalence of S. stercoralis infection increased significantly with age (P=0.041). Of the risk factors examined, both performing farming activities (P=0.001) and walking barefoot when going outside of the house (P=0.003) showed significant correlations with S. stercoralis infections. Our results suggest that S. stercoralis is highly endemic in this area. The National Helminth Control Program of Lao PDR should take actions to control S. stercoralis infection. In addition, provision of health education about the benefits of wearing shoes would be important for reducing infection in the study area. Moreover, the application of high-sensitivity diagnostic approaches is needed to obtain the true impact of S. stercoralis infections in all rural communities in order to provide surveillance activities in Lao PDR.