• Parasites, Hosts and Diseases
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• 제62권1호
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• pp.145-150
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• 2024

It is uncertain when the head collar and collar spines of Isthmiophora hortensis (Digenea: Echinostomatidae), a zoonotic echinostome species in Far Eastern Asia, develop during its larval stages. In this study, the appearance of the head collar and collar spines was studied using light and scanning electron microscopy in cercariae and metacercariae experimentally obtained from freshwater snails (Lymnaea pervia) and tadpoles (Rana nigromaculata), respectively. The cercariae were shed from the snail on day 30 after exposure to laboratory-hatched miracidia. Metacercariae were obtained from the experimental tadpoles at 3, 6, 12, 15, 20, 24, 26, and 30 h after exposure to the cercariae. The head collar was already visible in the cercarial stage, although its degree of development was weak. However, collar spines did not appear in the cercarial stage and even in the early metacercarial stage less than 24 h postinfection in tadpoles. Collar spines became visible in the metacercariae when they grew older than 24 h. It was concluded that the head collar of I. hortensis developed early in the cercarial stage, but the development of collar spines did not occur until the worms became 24-h-old metacercariae in our experimental setting. Counting the number of collar spines was concluded as an unfeasible diagnostic method for I. hortensis cercariae when they are shed from the snail host.

• 한국패류학회지
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• 제17권1호
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• pp.57-61
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• 2001

The present study examines the potential involvement of Biomphalaria glabrata, a known molluscan intermediate host of Schistosoma mansoni, in the life cycle of Echinostoma cinetorchis, one of the echinostomes that are ubiquitous parasites of vertebrates and are of importance in human and veterinary medicine and wildlife diseases. Echinostomes can be maintained easily and inexpensively in the laboratory and provide good models for biological research ranging from the molecular to the organismal. In the present study, no echinostome cercariae were released from the B. glabrata experimentally infected with E. cinetorchis miracidia, whereas all the Biomphalaria snails infected with E. cinetorchis cercariae were found to be infected with the metacercariae. This is the first report that B. glabrata can experimentally serve as the second intermediate host of E. cinetorchis, and that it might be employed as one of the target molluscs for establishing a biological research model with E. cinetorchis in the laboratory.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2000년도 춘계수산관련학회 공동학술대회발표요지집
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• pp.502-502
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• 2000

Corbicula fluminea Muller 1884 is the commonest freshwater bivalve in Asian countri including Korea. This clam is easily found in the freshwater systems, and edible as a food source in Korea. This study was aimed to confirm natural infection of C. fluminea collected from various localities with Echinostoma cinetorchis, an important hum intestinal fluke in Korea. (omitted)

• Parasites, Hosts and Diseases
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• 제39권3호
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• pp.247-253
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• 2001

Three freshwater snail species of the family Lymnaeidae have been reported from Korea, Radix auricularia coreana, Austropeplea ollula and Fossaria truncatula. Out of 3 lymnaeid snail species, A. ollula was naturally infected with the Echinostoma cinetorchis cercariae (infection rate : 0.7%). In the experiments with the laboratory-bred snails, F. truncatula as well as A. ollula was also susceptible to the E. cinetorchis miracidia with infection rates of 25% and 40%, respectively. All of three lymnaeid snail species exposed to the E. cinetorchis cercariae were infected with the E. cinetorchis metacercariae. It is evident that A. ollula acts as the first molluscan intermediate host of E. cinetorchis in Korea, and F. truncatula may be a possible candidate for the first intermediate host of this intestinal fluke. Also, three lymnaeid snail species targeted were experimentally infected with E. cinetorchis metacercariae.

• 한국어병학회지
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• 제1권1호
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• pp.31-37
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• 1988

해산이매패(海産二枚貝)의 흡충류감염종(吸蟲類感染種)과 패류(貝類)의 병해(病害)를 조사할 목적으로 서해안(西海岸) 금강하구(錦江河口) 내초도산(內草島産) 동죽, 가무락 조개 및 맛조개에서 극구흡충과(棘口吸蟲科)의 피낭유충(被囊幼蟲)을 검출(檢出)하였고, 맛조개에서 검출된 피양유충(被襄幼蟲)을 괭이갈매기에 감염(感染)시켜 16일(日)만에 성충(成蟲)을 얻었다. 1. 동죽 및 가무락조개에서는 Himasthla kusasigi의 피낭유충을 검출(檢出)하였으며, 기생율(寄生率)은 각각 70.4%, 85.7% 이었다. 2. 조직부위별(組織部位別) Himasthla kusasigi의 기생율(寄生率)은 족부(足部) 40.4%, 77.3%, 아가미 17.0%, 12.4%, 외투막 12.6%, 10.3% 순으로 기생(寄生)되었다. 3. 맛조개에서 Acanthoparyphium속(屬) 흡충(吸蟲)의 피낭유충(被囊幼蟲)을 검출(檢出)하였으며, 기생율(寄生率)은 63%, 조직부위별 기생율은 foot, mantle, gill 순(順)으로 기생(寄生) 되었다. 4. 맛조개에서 검출(檢出)된 피낭유충(幼蟲)을 괭이갈매기에 감염(感染)시켜 16일만에 성충(成蟲)을 분리하여 충체(蟲體)의 내부(內部)구조를 조사한바 Acanthoparyphium tyosenensis Yamaguti, 1938로 동정(同定) 되었다. 5. 동죽 및 가무락조개는 Himathla kusasigi의 새로운 중간숙주(中間宿主)로 추가되며, 본인(本人)(1968)등(等)이 개량조개에서 검출보고(檢出報告)한 Echinostoma속 흡충(吸蟲)은 Acanthoparyphium tyosenensis흡충(吸蟲)의 유충(幼蟲)임이 밝혀졌다.

• Animal Systematics, Evolution and Diversity
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• 제16권1호
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• pp.125-131
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• 2000

민물도요(Calidris alpina sakhalina)의 장에서 echinostome에 속하는 Himasthla(Dietz,1909) 속의 국내 미기록종을 발견하고 형태 및 분류학적 연구를 시도하였다. 새들은 경기도 강화군 여차리 일대에서 새 그물을 사용하여 포획하였다. 잡은 새들의 장에서 기생충을 분리하여 생리 식염수로 씻고 고정한 후, acetocarmine으로 연색한 후 현미경으로 관찰하였다. 발견된 Himasthla kusasigi(Yamaguti, 1939)는 작고, 길쭉한 형태로 전장 5.27mm 정도 였으며 31개의 가시가 달린 두관(0.27 mm) 을 갖고 있었다. 구홉반($0.057{\times}0.0684mm$)은 복홉반 보다 작았다. 복홉반($0.35{\times}0.29mm$)은 몸쪽 앞부분에 가깝게 위치하였다. 충체는 타원형의 전고환($0.47{\times}0.30mm$), 후고환($0.59{\times}0.27mm$) 두개의 고환을 갖고 있었다. 고환들은 충체 뒤쪽에 가깝게 위치하였다. 자궁은 길고 구불구불하였으며 충체 길이의 2/3 정도를 차지하였다. 난소($0.13{\times}0.14mm$)는 작고 둥글었다. 난소 아래에는 작고 둥근 수정낭이 보였다.

• Parasites, Hosts and Diseases
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• 제58권1호
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• pp.67-72
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• 2020

Human infection with Echinostoma aegyptica Khalil and Abaza, 1924 (Trematoda: Echinostomatidae) is extremely rare. In this study, we confirmed E. aegyptica infection in 5 riparian residents living along the Mekong River in Savannakhet Province, Lao PDR. The patients revealed eggs of Opisthorchis viverrini/minute intestinal flukes, echinostomes, and other parasites in fecal examinations using the Kato-Katz technique. Following treatment with praziquantel 30-40 mg/kg and pyrantel pamoate 10-15 mg/kg in a single dose and purging with magnesium salts, adult specimens of various helminth species were collected. Among the trematodes, echinostome flukes of 4.5-7.6 mm in length (n = 134; av. 22.3 specimens per case) were of taxonomic interest and subjected in this study. The flukes were morphologically characterized by having total 43-45 collar spines arranged in 2 alternating rows (corner spines usually 5 on each side) and compatible with previous descriptions of E. aegyptica. The patients were mixed-infected with other helminths, so specific clinical manifestations due to this echinostome fluke were difficult to determine. The present paper describes for the first time human E. aegyptica infections in Lao PDR. This is the second report of human infection (2nd-6th cases) with E. aegyptica in the world following the first one from China.

• Parasites, Hosts and Diseases
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• 제59권1호
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• pp.35-45
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• 2021

Adult echinostomes having 37 collar spines collected from the intestine of Pitalah ducks in Aceh Province, Indonesia in 2018 were morphologically and molecularly determined to be Echinostoma miyagawai Ishii, 1932 (Digenea: Echinostomatidae). Among 20 ducks examined, 7 (35.0%) were found to be infected with this echinostome, and the number of flukes collected was 48 in total with average 6.9 (1-17) worms per duck. The adult flukes were 7.2 (6.1-8.5) mm in length and 1.2 (1.0-1.4) mm in width (pre-ovarian or testicular level) and characterized by having a head collar armed with 37 collar spines (dorsal spines arranged in 2 alternating rows), including 5 end group spines, and variable morphology of the testes, irregularly or deeply lobed (3-5 lobes) at times with horizontal extension. The eggs within the worm uterus were 93 (79-105) ㎛ long and 62 (56-70) ㎛ wide. These morphological features were consistent with both E. miyagawai and Echinostoma robustum, for which synonymy to each other has been raised. Sequencing of 2 mitochondrial genes, cox1 and nad1, revealed high homology with E. miyagawai (98.6-100% for cox1 and 99.0-99.8% for nad1) and also with E. robustum (99.3-99.8% for nad1) deposited in GenBank. We accepted the synonymy between the 2 species and diagnosed our flukes as E. miyagawai (syn. E. robustum) with redescription of its morphology. Further studies are required to determine the biological characteristics of E. miyagawai in Aceh Province, Indonesia, including the intermediate host and larval stage information.

• Parasites, Hosts and Diseases
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• 제55권1호
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• pp.47-54
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• 2017

The prevalence of cercarial infection in freshwater snails and their evolutionary trends were studied in Nakhon Nayok province, Thailand. A total of 2,869 individual snails were examined for parasitic infections. The results showed that 12 snail species were found to host larval stages of trematodes with an overall prevalence of 4.7%. The infected specimens included 7 types at the cercarial stage; cercariae, megalurous cercariae, echinostome cercariae, furcocercous cercariae, parapleurolophocercous cercariae, virgulate cercariae, and xiphidiocercariae. Regarding molecular identification, ITS2 sequence data of each larval trematode were analyzed, and a dendrogram was constructed using the neighbor-joining method with 10,000 replicates. The dendrogram was separated into 6 clades (order/family), including Echinostomatida/Echinostomatidae, Echinostomatida/Philophthalmidae, Opisthorchiida/Heterophyidae, Plagiorchiida/Prosthogonimidae, Plagiorchiida/Lecithodendriidae, and Strigeatida/Cyathocotylidae. These findings were used to confirm morphological characteristics and evolutionary trends of each type of cercariae discovered in Nakhon Nayok province. Furthermore, this investigation confirmed that the ITS2 data of cercariae could be used to study on phylogenetic relationships or to determine classification of this species at order and/or family level when possible.

• Parasites, Hosts and Diseases
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• 제39권4호
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• pp.329-332
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• 2001

More than 1,500 clams of Corbicula fluminea, the most favorable food source of freshwater bivalves in Korea, were collected from 5 localities to examine cercarial and metacercarial infection with Echinostoma cinetorchis. Although 3 clams infected with suspicious E. cinetorchis metacercariae out of 200 specimens collected at Kangjin, Chollanam-do were detected, no cercarial and metacercarial infections with E. cinetorchis were observed in field-collected Corbicula specimens. In the susceptibility experiments with laboratory-reared clams, those infected with miracidia of E. cinetorchis did not release their cercariae up to 60 days after infection. To confirm the identity of second intermediate host of E. cinetorchis experimentally, a total of 30 clams were exposed to the cercariae from Segmentina hemisphaerula that had been infected with miracidia of E. cinetorchis. The clams were susceptible to cercariae of E. cinetorchis with an infection rate of 93.3%. Metacercariae from clams taken more than 7 days after cercarial exposure were fed to rats (S/D strain), and adult worms of E. cinetorchis, characterized by 37-38 collar spines on the head crown, were recovered from the ileocecal regions. This is the first report of C. fluminea as a possible second intermediate host of E. cinetorchis.