• Parasites, Hosts and Diseases
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• v.51 no.6
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• pp.621-627
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• 2013

Paragonimiasis is a food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. In Vietnam, research on Paragonimus and paragonimiasis has been conducted in northern and central regions of the country. Using a combination of morphological and molecular methods, 7 Paragonimus species, namely P. heterotremus, P. westermani, P. skrjabini, P. vietnamensis, P. proliferus, P. bangkokenis, and P. harinasutai, have been identified in Vietnam. Of these, the first 3, P. heterotremus, P. westermani, and P. skrjabini, are known to infect humans in other countries. However, in Vietnam, only P. heterotremus, found in some northern provinces, has been shown to infect humans. Even nowadays, local people in some northern provinces, such as Lai Chau and Yen Bai, are still suffering from P. heterotremus infection. In some provinces of central Vietnam, the prevalence and infection intensity of P. westermani metacercariae in freshwater crabs (the second intermediate hosts) are extremely high, but human cases have not been reported. Likewise, although P. skrjabini was found in Thanh Hoa Province, its pathogenicity to humans in Vietnam still remains uncertain. The results of molecular phylogenetic analyses of Vietnamese Paragonimus species provides new insights on the phylogeny and taxonomy of the genus Paragonimus. Comprehensive molecular epidemiological and geobiological studies on the genus in Vietnam and adjacent countries are needed to clarify the biodiversity and public health significance of the lung flukes.

• Applied Microscopy
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• v.27 no.4
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• pp.403-416
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• 1997

In order to observe the localization of the specific antigenic protein in the tissue of Paragonimus westermani metacercaria, immunogoldlabeling method was applied using IgG of the dog which were infected with Paragonimus westermani metacercaria and IgG of rabbits which were immunized with purified 23 kDa protein from metacercaria of the Paragenimus westermani. The metacercaria worm tissues obtained from Cambaroides similis were embedded in Lowicryl HM20 medium, treated with infected and immunized IgG and protein A gold complex (particle size; 12 nm) and observed by electron microscope. In the tissue antigen of Paragonimus westermani metacercaria, the content of excretory bladder which was highly dense electron density was constituted in the excretory bladder of the parenchymal tissue. In the metacercaria tissues antigen reacted with IgG of infected dog. Labeled gold particles distributed on the interstitial matrix of parenchymal cells, fibrous granules of parenchymal tissue and the content of excretory bladder. High antigenicity was observed on content of excretory bladder. It was found to be specifically distributed at the tissue of Paragonimus westermani metacercaria. In the tissues antigen reacted with IgG of immunized rabbit. Labeled gold particles randomly distributed on the interstitial matrix and fibrous granules of parenchymal tissue but in the content of excretory bladder of Paragonimus westermani metacercaria, gold particles were richly labeled. Therefore, the 23 kDa protein contained with Paragonimus westermani metacercaria was found protein which was specifically constituted at the content of excretory bladder of Paragonimum westermani metacercaria. The 23 kDa protein was commonly contained from of Paragonimus westermani metacercaria to adult and showed strong antigenicity against the immunized and infected IgG.

• Parasites, Hosts and Diseases
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• v.46 no.3
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• pp.179-182
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• 2008

As a part of a broader effort to determine the status of Paragonimus species infection in Lao PDR, an epidemiological survey was conducted on villagers and schoolchildren in Namback District between 2003 and 2005. Among 308 villagers and 633 primary and secondary schoolchildren, 156 villagers and 92 children evidenced a positive reaction on a Paragonimus skin test. Only 4 schoolchildren out of 128 skin test-positive cases had Paragonimus sp. eggs in their sputum, all of which was collected on 1 day. Several types of crabs, which were identified as the second intermediate host of the Paragonimus species, were collected from markets and streams in a paragonimiasis endemic area for the inspection of metacercariae. Among the examined crabs, only "rock crabs" (Indochinamon au) harbored Paragonimus sp. metacercariae, and it is speculated that the life cycle of Paragonimus sp. was maintained via rock crabs in Namback District, Lao PDR.

• Parasites, Hosts and Diseases
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• v.56 no.2
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• pp.189-194
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• 2018

To determine that Paragonimus sp. is actively transmitted in a tropical area of the Pacific region of Ecuador where human cases of pulmonary paragonimiasis have recently been documented, a total of 75 freshwater crabs were collected from 2 different streams in the Pedernales area of $Manab\acute{i}$ Province, Ecuador. All collected crabs were identified as Hypolobocera guayaquilensis based on morphological characteristics of the male gonopods. The hepatopancreas of each crab was examined by compressing it between 2 glass plates followed by observation under a stereomicroscope. Excysted Paragonimus metacercariae were detected in 39 (52.0%) crabs and their densities varied from 1 to 32 per infected crab. There was a positive relationship between crab size and metacercarial density. Sequences of the second internal transcribed spacer region of the ribosomal RNA gene of the Paragonimus metacercariae obtained in this study were identical to those of Paragonimus mexicanus deposited in the DDBJ/EMBL/GenBank database. Thus, the present study is the first to confirm that the crab species H. guayaquilensis is the second intermediate host of P. mexicanus in $Manab\acute{i}$ Province, Ecuador. Because this crab might be the possible source of human infections in this area, residents should pay attention to improper crab-eating habits related with a neglected parasitic disease, i.e., paragonimiasis.

• Journal of agricultural medicine and community health
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• v.6 no.1
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• pp.5-12
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• 1981

Paragonimus infection is prevalent in Korea, establishing several endemic foci. Kim(1969) reported an endemic area in Hyeonbuk Myeon. Yangyang-Gun, but thereafter no further epidemiologic study of Paragonimus infection was performed in the Gangweon-Do. Hoengseong-Gun is mountainous area which is located in the southwestern part of Gangweon-Do and borders with Hongcheon-Gun on the east, with Pyeongchang-Gun on the east, with Yeongweol-Gun and Weonseong-Gun on the south, and with Yangpyeong-Gun on west. The author carried out an epidemiologic study of Paragonimus infection by intradermal test with V.B.S antigen, and of intermediate host (crayfish) in Hoengseong-Gun, Gangweon-Do. The results are summarized as follows: 1. The positive skin test reaction to Paragonimus antigen was 14.5% from 2,807 examiness; 16.0% in male and 11.6% in female and no sex or age difference on the skin test positive reactions was noticed among the villages. 2. The positive skin test reactions were 31.3% in Gapcheon-Myeon, 20.5% in Cheongil-Myeon and 19.8% in Woocheon-Myeon. Primary school children in Byeongjibang-ri, Gapcheon-Myeon showed positive in 36.4%. 3. The prevalence by skin test reaction by social strata was 16.1% (226 out of 1,408) in primary school children, 12.8% out of 725) in middle school, 6.4% (11 out of 172) in high school students, and 15.3% (77 out of 502) in inhabitants of Heongseong-Gun. 4. Metacercarial positives of Paragonimus in crayfish were 20.9%. Through the survey results, it is postulated that Heongseong-Gun, Gangweon-Do is to be categorized as an endemic area of Paragonimus infection.

• Journal of Life Science
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• v.5 no.1
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• pp.20-25
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• 1995

기생충감영시 cytokine으로 활성화된 대식세포가 방어기전의 Effector cell로 작용할 때 분비하는 nitric oxide의 양 및 TNF-$\alpha$ 와 IFN-$\gamma$의 분비정도와 nitric oxide와의 상관관계 등을 알아보기 위하여 3종의 흡충류, Fasciola, paragonimus, Schistosma의 조항원 (100mg/ml)을 마우스 복강내에 주사　 후 24시간, 72시간, 9일간격으로 마우스의 대식세포(1X10$^{6}$/ml)를 분리하여 RPMI 배지 (10% FCS 첨가)에서 48시간 배양후 Nitric TNF-$\alpha$ 및 IFN-$\gamma$를 ELISA로 정량하여 다음과 같은 결과를 얻었다. Nitrite 생성정도는 Fasciola 조항원으로 24시간 감작시킨 대식세포에서 가장 높게 나타났으며 (140$\mu$M/ml) Paragonimus 항원군에서는 24시간에 최고치에 달하였다가(34 $\mu$M/ml) 시간이 경과함에 따라 점차 감소하였다. IFN-$\gamma$는 Paragonimus 항원군에서만 대조군에 비해 높았으며 9일경에 최고치를 보였다(475ng/ml). TNF-$\alpha$는 Schistosoma 항원군에서는 nitric oxide의 생성과 분비 양상이 일치하였다. 위의 결과에 의하면, 흡충류항원으로 감작된 마우스 대식세포의 nitric oxide 생성에 영향을 미치는 cytokine의 종류는 흥충류에 따라 차이를 보였으며, 이 중 Paragonimus 항원에 의해서는 IFN-$\gamma$의 분비가 촉진되는 것으로 나타났고, Schistosoma 의 경우에는 TNF-$\alpha$가 nitric oxide의 생성에 관계함을 알 수 있었다.

• Parasites, Hosts and Diseases
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• v.37 no.1
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• pp.55-57
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• 1999

During the period from October 1996 to November 1998, the infection status of Paragonimus westermani metacercariae in freshwater crayfish (Cambaroides similis) collected from Bogildo (islet), Wando-gun, Chollanam-do, which is known for an endemic area of P. westermani in Korea, were examined. The average infection rate of Paragonimus metacercariae in crayfish was 88.6%, and mean number of metacercariae per infected crayfish was 30.2. This metacercarial density was the highest in the group of weight in 7.1-9.0 g. These results suggest that the natural life cycle of P. westermani is still well-preserved in Bogildo.

• The Korean Journal of Malacology
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• v.1 no.1
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• pp.19-23
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• 1985

Collections of Semisulcospira snails and crayfishes were made to detect out larval trematodes in Bogil Islet, Wando-Gun, Chonra-Nam-Do, Korea in August, 1985. In addition, intradermal test to figure out the prevalence rate of paragonimiasis in the islanders was also carried out. The results are summarized as follows: 1) Nineteen out of 186 examinees(10.2%) showed positive reactions by intradermal test with Paragonimus antigen. 2) Forty four snails out of 182 snails collected were infected with trematode cercariae. These larvae were Metagonimus sp., Cercaria yoshidae, Cercaria incerta and Cercarianipponensis. 3) Metacercarial incidence of Paragonimus westermani in crayfish was 65.4%. Mean number of metacercariae per crayfish was 6.5.

• Journal of the korean veterinary medical association
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• v.5 no.1
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• pp.38-38
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• 1961

The first case in Korea of Paragonimus westermanni(Human lung fluke) in the cat is recorded with gross-histo-pathological findings.

• Parasites, Hosts and Diseases
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• v.29 no.1
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• pp.43-54
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• 1991

An in vitro immune effector mechanism against the target encysted metacercariae of Paragonimus westermani was demonstrated in the rat system. Peritoneal exudate cells, mainly macrophages from normal rats, showed adherence to and killing of encysted metacercariae of p. westermani in the presence of complement-independent serum from rats infected with Paragonimus metacercariae. These reactions were specific for the excysted metacercariae, as tissue-migrating juvenile worms were not affected. Damage of encysted metacercariae of p. westermani due to antibody and macrophages was assessed by morphological observation, by cell adherence reaction and by the use of vital dyes. frypan blue dye exclusion proved to be a reliable indicator of judging metacercarial viability. Electron microscopic studies demonstrated that macrophages reacted with fusty material on the tegumental surface and fine structures in the syncytium of the parasites. The tubular tunnels formed between the basement membrane and muscle layers of the damaged parasites were also noticeable. The relevance of these findings to cellular immunity in the early paragonimiasis was discussed.