• Parasites, Hosts and Diseases
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• v.27 no.3
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• pp.197-202
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• 1989

This study was performed to observe the susceptibility of dogs and cats as definitive hosts of Paragonimus ilektsuenensis. The metacercariae of this luke were obtained from Sesarma dehaani collected at a focus near the mouth of Sumjin river in November, 1986 and February, 1987. The larvae isolated from the crabs were introduced Per os into 7 albino rats, 2 dogs and 3 cats. The adults were recovered from the experimental animals, End they were morphologically observed and measured. The results were as follows: 1. The recovery rate of adult worms at 42 days after infection was 53.3% from three albino rats, 21.0% from a dog and 12.7% from two cats. Most of the worms were recovered from the worm capsules in the lungs. 2. The size of worms recovered from albino rats, a dog, and cats 42 days after infection aver-aged $6.3{\times}3.2mm,{\;}6.3{\times}3.0mm,{\;}or{\;}6.2{\times}3.5mm$, respectively. There were little differences in the morphology of worms by different experimental animals. 3. The size of eggs from a dog was $88.9{\times}49.3{\mu\textrm{m}}$, and that from cats was $84.3{\times}53.7{\mu\textrm{m}}$ on average. Dogs and cats were good definitive hosts of p. iloktsuenensis. This fact suggests that human infection by this luke may be possible if the metacercariae were ingested.

• Korean Journal of Veterinary Research
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• v.33 no.4
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• pp.679-691
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• 1993

As a series of studies to investigate the effect of immunosuppression on Ascaris suum infection in undefinitive hosts, a delicate relationship between host and parasite, rabbits were divided into experiment 1(control group) and experiment 2(immnunosuppressive group treated with prednisolone acetate) and inoculated with a single dose of 5,000 embryonated A suum eggs. The recovery rates, sizes and morphology of the larvae and immunological responses in the rabbits were chronologically monitored according to somatic migration. In both experiments, the larvae failed to develop into the adults, but young adults in the experiment 2 grew somewhat faster and survied later than those in the experiment 1. The mast cells of small intestinal mucosa and mesenteric lymph nodes and the goblet cells of small intestinal mucosa in the worm detected cases of experiment 2 decreased remarkably in number comparing with those of experiment 1. Considering the experimental results. the expulsion mechanism of somatic migrant larvae may he related to the temporary increasing tendency of the mast cells, the goblet cells, T-cells of mesenteric lymph nodes and spleens, eosinophils in peripheral blood, degranulation rates of peritoneal mast cells and the migration inhibition rates of leucocytes. In addition, patent infection of A suum in the rabbits was not obviously observed despite of immunosuppression by prednisolone acetate.

• Parasites, Hosts and Diseases
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• v.59 no.4
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• pp.341-353
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• 2021

Acanthoparyphium shinanense n. sp. (Digenea: Echinostomatidae) is described from chicks experimentally infected with the metacercariae encysted in 2 brackish water clam species, Ruditapes philippinarum and Coecella chinensis, in the Republic of Korea. The metacercariae were round to oval, armed with 23 collar spines, and 0.216 (0.203-0.226) mm in diameter. From 5 chicks experimentally infected each with 200 metacercariae, 34 juvenile (5-day-old worms) and 104 adult flukes (7-day-old worms) were harvested from their small intestines, with the average worm recovery rate of 13.8%. The adult flukes were 3.18 (2.89-3.55) mm long and 0.68 (0.61-0.85) mm wide, with an elongated, posteriorly tapering body, and a prominent head collar armed with 23 collar spines arranged in a single uninterrupted row. The posterior testis of A. shinanense was longitudinally elongated, which is similar to Acanthoparyphium spinulosum Johnston, 1917 but unique from the other closely related species, including Acanthoparyphium tyosenense Yamaguti, 1939, Acanthoparyphium kurogamo Yamaguti, 1939, and Acanthoparyphium marilae Yamaguti, 1934. The eggs of A. shinanense were larger than those of A. spinulosum, and the anterior extent of 2 lateral groups of vitellaria was slightly more limited in A. shinanense than in A. spinulosum. Molecular analysis of nuclear and mitochondrial genes revealed low homology with A. spinulosum from USA (96.1% in 5.8S rRNA) and Ukraine (97.9% in 28S rRNA), Acanthoparyphium n. sp. from USA (98.0% in 28S rRNA), and Acanthoparyphium sp. from Australia, Kuwait, and New Zealand. Biological characteristics, including its first intermediate host and natural definitive hosts, as well as its zoonotic capability, should be elucidated.

• Journal of Sericultural and Entomological Science
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• v.15 no.2
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• pp.15-20
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• 1973

This will be second publication regard with silkworm selection using anesthetic followed by previous report. This treatise investigated for nacorsis recovery concerned with silkworm health through more directions than the previous paper. After the author has found a possibility of silkworm seperation through nacorsis recovery, he has recommended to use Balance Health (BH) value system to evaluate or identify silkworm health and to produce better homogeneous silkworm eggs. Also, the author has continued the observation for the next generation how once nacortized parents affect to their family. The obtained results are summarized as followings. 1. Basic investigation a) Hybrid silkworm variety recovers from nacorsis earlyer than pure line because it is stronger. b) Strong pure line variety recovers from nacorsis earlyer than weak one because it is stronger. c) Male worm recovers from nacorsis earlyer than female worm because it is stronger. 2. Establishment of Balance Health(BH) value system. In order to identify each seperated group by nacorsis and their family, the following Balance Health (BH) value indicating system was established.(Table Omitted) 3. In order to select better silkworm during breeding service, the BH value indicating system is strongly recommended. That is, in case BH value is smaller than four, it would be strong group or in case BH value is larger than four, it would be weak group. 4. Once nacortized parents do not harm any nature for next generation regardless P$_1$ or F$_1$ production. 5. The seperation through nacorsis may delay retrograde phenomenon some years than other case, so, this system should be used for pure line production every year. 6. It is recommended to nacortize silkworm for five minutes on breeding purpose, but two and half minutes on pure lines reproduction at fifth instar. 7. This report has been discussed in relation to practical industry promotion aspects, but there are many subjects to be solved from academical aspect in future

• Parasites, Hosts and Diseases
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• v.27 no.3
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• pp.187-196
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• 1989

The effects of gamma irradiation on the survival and development of C. sinensis metacercariae were studied to evaluate the feasibility of irradiation as a control measure for clonorchiasis. Pseudorasbora parve were collected at an endemic river of clonorchiasis and were used for irradiation of the fluke in three schemes. The first (Scheme 1) was irradiation of the isolated metacercariae from the fish followed by infection to experimental rats. The second (Scheme 2) was irradiation of the fish, and then the metacercariae were isolated and in(ected to rats. The third (Scheme 3) was irradiation on the rat livers after infection with normal metacercariae. Irradiation doses varied from 5 to 100 Gy for Schemes 1 and 2, and 10 to 25 Gy for Scheme 3. The rats were sacrificed 2 to 6 weeks after infection. In Scheme 1, the metacercariae irradiated at 50 Gy failed to survive in the rats after 2 or 6 weeks. However, 1 to 44% of the metacercariae irradiated at 5∼30 Gy survived. The estimated LD50 of Scheme 1 was 16.5 Gy. The flukes irradiated in Scheme 2 survived better than those in Scheme 1. The average worm recovery rate in 50 Gy was 28%(7∼39% individually). Increasing the dose up to 100 Gy brought a remarkably low survival rate of an average 1%(0∼3% individually). The LD50 of Scheme 2 was 47.5 Gy. Worm recovery rates in the 10 Gy group of Scheme 3 were 21∼39%, and those in the 25 Gy group were 2% and 34%. Although the metacercariae were irradiated, all of the recovered worms were morphologically normal. Only the worms irradiated with 10 Gy or 25 Gy after 9 days from infection in Scheme 3 showed underdeveloped testes and seminal receptacle. The present results suggest that irradiation of the fish by 100 Gy could be adopted as a control measure for clonorchiasis.

• Parasites, Hosts and Diseases
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• v.33 no.4
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• pp.297-304
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• 1995

To evaluate the feasibility of irradiation as a control measure for metagonimiasis, the metacercariae of Metagonimus yokogcwni were irradiated with gamma ray, either after isolation from the sweetfish (Plecoglossus cltivelis) or in situ of the fish, and their survival and development in rats were observed at 7 days post-infection. The radiation dose varied from 5 to 100 Gy for the metacercaria-irradiation group and from 5 to 500 Gy for fish-irradiation group. The results showed that the worm recovery rate from the irradiation groups decreased as the radiation dose was increased. Higher doses of radiation were required for the fish-irradiation group to obtain the same results as the metacercaria-irradiation group. The LD50 of the metacercaria-irradiation group was 4.5 Gy, whereas that of the fish-irradiation group 6.2 Gy A few number of worms which survived until 7 days in rats were severely retarded especially in the growth of their reproductive organs, j.e., complete or partial failure in the development of testes and formation of uterine eggs . The present study revealed that irradiation of sweetfish by 200 Gy is effective to control infectivity as well as development of M. vokogawai metacercariae in rats.

• Parasites, Hosts and Diseases
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• v.29 no.1
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• pp.9-20
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• 1991

The present study intended to evaluate the influences of MetagonimMi yokogawai on the activities of brush border membrane bound enzymes of the small intestine. Mice were infected with 500 metacercariae respectively, and the worm recovery, morphological changes and enzyme activities were observed chronologically. A part of them were followed after the treatment. Recovered worms decreased in number continuously after the infection, and they were less than 10% after 2 weeks and almost Bero after 28 weeks. Villous atrophy and stromal inflammation were found at two locations of the proximal jejunum from 2 weeks to 4 weeks after the infection. The enzymes, alkaline phosphatase, leucine aminopeptidase and disaccharidases (sucrase, lactase, maltase, and trehalase), showed lowered activities in the duodenum and proximal jejunum of the infected mice but they increased in the distal jejunum for the first two weeks. From three weeks after the infection, the activities were gradually recovered. In one week treated mice, they recovered the activities at 2 weeks from the treatment, but there found no differences of the activities between the 3 week treated group and infected controls. The present data reveal that M. yckogawai infection induces degenerative changes of the host's intestinal mucosa not only morphologically but functionally during the initial phase of infection. The lowered enzyme activities in acute metagonimiasis should be associated with malabsorption and diarrhea.

• Parasites, Hosts and Diseases
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• v.28 no.1
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• pp.1-10
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• 1990

To establish an animal model of intracranial sparganosis, the fate and behavior of the experimentally inoculated spargana were observed. A total of 102 scolices of spargana were injected into 22 cat brains, and the cats were sacrificed at 2 weeks, 1 month, 3 months and 6 months after the inoculation. Neurosparganosis was established in 77% of the cats. Of 43 recovered worms,19 (44%) were located in the subdural or subarachnoid space,16 (37%) in the brain Parenchyme, and 2 (5%) in the lateral ventricle. One was detected at the diploic space of the skull and 5 were outside the cranial cavity. All but one were alive, and had grown tails. They were distributed in the brain parenchyme randomly. There was no place which they could not invade. No adult was found in the intestine. Cerebrospinal fluid (CSF) was collected before inoculation, 1 week, 2 weeks, 1 month, 3 months and 6 months after inoculation. The level of anti-sparganum IgG antibody in CSF measured by ELISA began to increase above the criteria of positivity 1 month after inoculation. Three months after inocula- tion, the values markedly increased. The present findings reveal that intracranial inoculation of spargana into the brains of cats would be a good animal model of experimental neurosparganosis.

• Parasites, Hosts and Diseases
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• v.30 no.4
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• pp.237-244
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• 1992

In order to observe the infectivity, growth and development and adult morphology of Metorchis orientalis, a total of 40 chicks were experimentally infected with 100 metacercariae respectively, collected from Pseuderasbora larva. The worms of various developmental stages were recovered from chicks at 1.5, 3, 5, 7, 9, 11, 1:k and 21 days after infection, and they were prepared for morphological observations and measurements. All of the worms were found in the gallbladders of chicks, and their recovery rate was 32% in average. The growth of the body was rapid from 9 to 11 days after infection. The genital primordia appeared in 1.5 and 3-day old worms, and ovary and testes were first observed in 5-day old worms. Thereafter, genital organs gradually matured and completed up to 11 days after infection. The adult worm was leaf-like, and possessed a con- voluted tubular seminal vesicle, an ovoid ovary, a sac-like seminal receptacle, 2 lobed-testes and follicular vitellaria. Eggs were $31.9{\times}15.3{\;}\mu\textrm{m}$ in average size, ellipsoid to elliptical in shape and possessed abopercular thickenings. From the above results, it is concluded that M. orientalis grows in sigmoid pattern in chicks, and their genital organs fully matul.e between days 9 and 11. It is also confirmed that a chick is a new definitive host of M. orientalis.

• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.41-46
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• 1985

The therapeutic effects of praziquantel on Fibricola seoulensis infection were studied by experimental infection of albino rats with the metacercariae obtained from the snakes. Total 51 albino rats were infected each with 500 or 1, 000 meta cercariae in number through intragastric tubes. One or four weeks la er the rats were treated with 1, 5, 10 or 20 mg/kg single dose of prazipuantel and sacrificed after 3 days or 10-120 minutes to search for the worms in their small intestine. The worm recovery rate at 3 days after the treatment was 10.7 % in 1 mg/kg dose group and o. 03~0.2% in 5, 10 and 20 mg/kg groups, while that of untreated control was 51. 3%. The minimum effective dose to treat F. seoulensis infection in the rats is considered to be 5 mg/kg in single dose. By observing the distribution pattern of worms in the small intestine after the treatment, dislodgement of the worms from the duodenum, their normal habitat, to the lower portions was recognizable within as early as 10 minutes. The majority of worms was found to have descended to the ileo-caecal portion after 60-120 minutes.