• Parasites, Hosts and Diseases
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• 제53권1호
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• pp.59-64
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• 2015

This study was conducted to investigate the life history, morphology, and maturation of larval stages and adult worms of Fasciola gigantica in experimental mice. Lymnaea auricularia rubiginosa was used as the intermediate host, and Oryza sativa was used for encystment of the metacercariae, while Mus musculus was used as the definitive host for maturation study. Fresh eggs from the gall bladder of water buffaloes fully developed into embryonated ones and hatched out at days 11-12 after incubation at about $29^{\circ}C$. Free-swimming miracidia rapidly penetrated into the snail host, and gradually developed into the next larval stages; sporocyst, redia, and daughter redia with cercariae. Fully-developed cercariae were separated from the redia and shed from the snails on day 39 post-infection (PI). Free-swimming cercariae were immediately allowed to adhere to rice plants, and capsules were constructed to protect metacercariae on rice plants. Juvenile worms were detected in intestines of mice at days 3 and 6 PI, but they were found in the bile duct from day 9 PI. Juvenile and adult flukes were recovered from 16 mice experimentally infected with metacercariae, with the average recovery rate of 35.8%. Sexually mature adult flukes were recovered from day 42 PI. It could be confirmed that experimentally encysted metacercariae could infect and develop to maturity in the experimental host. The present study reports for the first time the complete life history of F. gigantica by an experimental study in Thailand. The obtained information can be used as a guide for prevention, elimination, and treatment of F. gigantica at environment and in other hosts.

• Parasites, Hosts and Diseases
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• 제29권4호
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• pp.325-338
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• 1991

경북 영양지역 주민들의 흡충류 감염실태와 제2중간숙주 담수어의 흡충류 피낭유충의 기생상을 규명하기 위해 역학조사를 시행하였다. 충란검사는 반정량적 formalin-ether 집란법에 의거하였고 흡충류 충란양성자는 Stoll씨 충란계산법으로 감염정도를 추정하였다. 흡충류 피낭유충의 기생상은 슬라이드 글라스 여박법과 인공소화법으로 조사하였다. 피검자 955명중 18.5%(177명)에서 요충군이 검출되었고 그 중 흡충류 충란은 간흡충 단독감염자 7.3%(70명), 이형흡충류 단독감염자 7.7%(74명), 간흡충과 이형흡충류 이중감염자 2.5%(24명), 간흡충과 경충 이중감형자 0.1%(15명), 및 간질 위감염자 0.1%(1명)으로 17.9%(171명)에서 검출할 수 있었다. 성별 간흡충 감염은 남성 675명중 12.6%(85명), 여성 280명중 3.6%(10명)으로 남성에서 유의적으로 높았다. 이형흡광류 감염 역시 남성 675명중 12.0%(81명), 여성 380명중 6.1%(17명)으로 남성에서 유의적으로 높았다. 감염정도도 우흡충 모두 남성에서 여성보다 높았다. 연령별로는 30세 이상군에서 30세 미만군보다 심한 감염정도를 나타내었다. 10∼19세군에서는 양 흡충류의 감염자가 없었다. 감염정도와 연령사이에는 유의한 연관을 인정할 수 없었다. 반변천에서 채집된 8종의 담수어중 횡천흡충 피습유충의 기생률과 고 정도는 각각 갈겨니에서 57.5%, 12.4개로 가장 높았고 동사리에서 6.8%, 0.2개로 가장 낮았으며 피래미에서 55.4%, 1.3개로 중간을 나타내었다. 간흡충 피낭유충은 몰개에서만 기생률 23.3%, 그 기생정도 2.1개로 나타났다. 이상의 성적으로 미루어 보아 경북 영양지역은 간흡충과 이형흡충류의 만연지임을 알 수 있었다.

• Journal of Preventive Medicine and Public Health
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• 제4권1호
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• pp.35-39
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• 1971

The authors examined the Ascaris eggs on the surface of the strawberries and in the soil of the strawberry yards. The results were as follows: 1. The number of Ascaris eggs detected from 870 strawberries grown on strawberry yards was 26, of which 17 eggs were found to be alive. 2. The mean number of Ascaris eggs detected in every 10gm of the soil of strawberry yards was 10.3. The Ascaris eggs were detected over 93% from the yards examined, which had been fertilized with both chemical fertilizer and night soil, or night soil only. 3. No Ascaris eggs was found from strawberries which were produced only with chemical fertilizer. 4. Ascaris eggs were detected 6 from 705 marketing strawberries studied, 3 of them developed to larval stage. 5. when the strawberries were washed by shaking 20 times after kept immersed in water for 10 minutes, the recovery rates of Ascaris eggs after first, 2nd, 3rd, 4th and 5th washing were 60, 87, 96, 99 and 100%, respectively. 6. Besides Ascaris eggs of hook worm and Fasciolidae were also found from the strawberries examined.

• Parasites, Hosts and Diseases
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• 제54권2호
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• pp.173-179
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• 2016

Echinostoma hortense (Digenea: Echinostomatidae) is one of the intestinal flukes with medical importance in humans. However, the mitochondrial (mt) genome of this fluke has not been known yet. The present study has determined the complete mt genome sequences of E. hortense and assessed the phylogenetic relationships with other digenean species for which the complete mt genome sequences are available in GenBank using concatenated amino acid sequences inferred from 12 protein-coding genes. The mt genome of E. hortense contained 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 non-coding region. The length of the mt genome of E. hortense was 14,994 bp, which was somewhat smaller than those of other trematode species. Phylogenetic analyses based on concatenated nucleotide sequence datasets for all 12 protein-coding genes using maximum parsimony (MP) method showed that E. hortense and Hypoderaeum conoideum gathered together, and they were closer to each other than to Fasciolidae and other echinostomatid trematodes. The availability of the complete mt genome sequences of E. hortense provides important genetic markers for diagnostics, population genetics, and evolutionary studies of digeneans.

• Parasites, Hosts and Diseases
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• 제56권5호
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• pp.453-461
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• 2018

The aim of this study is to delineate 'admixed hybrid' and 'introgressive' Fasciola genotypes present in the Fasciola population in Vietnam. Adult liver flukes collected from ruminants in 18 Provinces were morphologically sorted out by naked eyes for small (S), medium (M) and large (L) body shapes; and human samples (n=14) from patients. Nuclear ribosomal (rDNA) ITS1 and ITS2, and mitochondrial (mtDNA) nad1 markers were used for determination of their genetic status. Total 4,725 worm samples of ruminants were tentatively classified by their size: 6% (n=284) small (S)-, 13% (n=614) medium (M)-, and 81% (n=3,827) large (L)-forms. All the representative (n=120, as 40 each group) and 14 human specimens, possessed maternal mtDNA of only F. gigantica and none of F. hepatica. Paternally, all (100%) of the L-(n=40) and 77.5% (n=31) of the M-flukes had single F. gigantica rDNA indicating 'pure' F. gigantica. A majority (90%, n=36) of the S- and 15% (n=6) of the M-worms had single F. hepatica rDNA, indicating their introgressive; the rest (10%, n=4) of the S- and 7.5% (n=3) of the M-flukes had mixture of both F. gigantica and F. hepatica rDNAs, confirming their admixed hybrid genetic status. Fourteen human samples revealed 9 (64%) of pure F. gigantica, 3 (22%) of introgressive and 2 (14%) of admixed hybrid Fasciola spp. By the present study, it was confirmed that the small worms, which are morphologically identical with F. hepatica, are admixed and/or introgressive hybrids of Fasciola spp., and able to be the pathogens of human fascioliasis.