• 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.

• Parasites, Hosts and Diseases
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• v.27 no.2
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• pp.119-130
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• 1989

An experimental pathological study was performed to observe the effect of prasiquantel treat- ment on the pulmonary lesions of the rat lung cuke, Paragonimus ilektsuenensis. The metacercariae were obtained from the freshwater crab, Sesarma dehaani, and 40 rats (wistar) were fed each with 10 metacercariae. On 20 rats prasiquantel treatment ($100mg/kg/day{\times}5$ days) was done at 5 weeks after the infection while remaining 20 rats were kept untreated for use as controls. The drug.treated rats and the untreated ones were sacrificed 3, 7, 14, 21 or 28 days later for the observation of lung pathology. The rats infected with P. iloktsuenensis showed remarkable pulmonary changes; gross features of hemorrhagic and nodular worm capsules protruded on to the surface of the lung, and histologically local atelectasis, inflammatory cell infiltration, and egg granuloma around the worm capsules each containing one or two worms. Praziquantel treatment of the rats was shorn to be highly effective in killing the worms and to lead them to degenerate, as early as in 3 days post-treatment. Almost all worms in the lung were dead and absorbed by the host cells in 21 days post-treatment, except a few living ones seen in a rat of 14-day post-treatment group. In most of the rats treated the pulmonary lesions showed the signs of resolution; regression of worm capsules with mummification of worms, decrease of inflammatory cell infiltration, improvement in the degree of atelectasis, and decreases in the frequency and size of the egg granuloma. From the results it is concluded that prasiquantel is highly effective for the treatment of rat P. iloktsuenensis infection in the lung, not only by its direct killing effect of the worms but also due to the excellent resolution capacity of the pulmonary tissues.

• Parasites, Hosts and Diseases
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• v.50 no.4
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• pp.349-352
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• 2012

A 94-year-old female with end-stage renal disease presents with fever, fatigue, and hematochezia. She had previously resided in Hunan Province, China, and Myanmar, and she immigrated to Taiwan 30 years ago. Colonoscopy revealed a colonic ulcer. Biopsy of the colonic ulcer showed ulceration of the colonic mucosa, and many Paragonimus westermani-like eggs were noted. Serum IgG antibody levels showed strong reactivity with P. westermani excretory-secretory antigens by ELISA. Intestinal paragonimiasis was thus diagnosed according to the morphology of the eggs and serologic finding. After treatment with praziquantel, hematochezia resolved. The present case illustrates the extreme manifestations encountered in severe intestinal paragonimiasis.

• Journal of Environmental Health Sciences
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• v.44 no.2
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• pp.196-203
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• 2018

Objectives: The purpose of this study was to assess environmental risk on the emerging contaminants of concern, such as ivermetin, parziquantel, tamiflu and triclosan. Furthermore, we tried to provide a more efficient management practice and a basis for future studies of risk assessment on those substances. Methods: Predicted no effect concentration (PNEC) and predicted environmental concentration (PEC) were determined through modeling and literature reviews. Environmental risk assessment was evaluated by calculating HQ (hazard quotient) by a comparison of PEC (or measured environmental concentration (MEC)) and PNEC. Results: HQ value of tamiflu calculated from MEC was 1.9E-03. For ivermectin and triclosan, the HQ values were not available because these were not detected in the aquatic environment. The toxicity of ivermectin and triclosan showed a very low value, indicating a high level of HQ. However, praziquantel can be categorized into the material that do not require management since they have less than HQ 1. Conclusion: Based on the results of the initial risk assessment, it is assumed that the ivermectin and triclosan have potential to cause direct adverse effects on the aquatic environment. To conduct an accurate environmental risk assessment, the further study on PEC estimation of such contaminants should be actively carried out.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.43-50
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• 1984

Two cases of human infection by Stellantchasmus falcatus (Heterophyidae) were identified by collection of adult worms during the treatment of some tapeworm infections in Korea. The cases were 24 (Case 1) and 55-year old (Case 2) males residing in Seoul. The Case 1 had gastrointestinal troubles such as diarrhea and abdominal pain, and heart problems such as palpitation and arrhythmia, revealing the eggs of Diphyllobothrium latum in the feces. The Case 2 complained indigestion and discharge of tapeworm (Taenia saginata) segments. Praziquantel at the dose of 15-20mg/kg body weight and 30 g magnesium salt were given to them for treatment of the tapeworm infections and the discharged strobilae were identified. However, concommitantly with the tapeworms, 188 and 5 specimens of S. falcatus were collected from Case 1 and Case 2 respectively through stereomicroscopy of the diarrheal stools. The Case 1 was infected also with 3 other kinds of heterophyid flukes. They said to have eaten raw brackish water fish such as mullets which are considered to be the source of heterophyid fluke infections.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.61-65
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• 1984

A mass fecal examination was performed in Seoul, Korea from December 1983 to March 1984 and 15 egg positive cases of Fibricola seoulensis were discovered. They were treated with praziquantel($Distocide{\circledR}$) 20mg/kg single dose and magnesium salt for purgation. The adult worms of F. seoulensis were collected from 6 of them. The number of the flukes ranged 1-78 by the case. The cases had no clinical manifestation at all. They were all Korean males in twenties, and had the histories of eating the roast or raw snakes or frogs. Fibricoliasis is expected to be prevalent among the snake-eaters in Korea. Further cases will be detected by sedulous differentiation of thinshelled immature operculated eggs of 0.08~0.102mmn length. Praziquantel seems to be an excellent chemotherapeutic for fibricoliasis.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.7011-7016
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• 2013

Background: The liver fluke, Opisthorchis viverrini, and the associated incidence of subsequent cholangiocarcinoma (CCA) are still a public health problem in Thailand, and praziquantel (PZQ) remains the antihelminthic drug of choice for treatment. Evidence in hamsters shows that repeated infection and PZQ treatments could increase the risk of CCA. However, the existing evidence in humans is inconclusive regarding increased risk of CCA with frequency of PZQ intake. Objectives: To investigate the relationship between number of repeated PZQ treatments and CCA in patients with O viverrini infection. Materials and Methods: The reviewed studies were searched in EMBASE, MEDLINE, ProQuest, PubMed and SCOPUS from inception to October, 2012 using prespecified keywords. The risk of bias (ROB) of included studies was independently assessed by two reviewers using a quality scale from the Newcastle-Ottawa Scale (NOS). Risk effect of PZQ was estimated as a pooled odds ratio (OR) with its 95% confidence interval (95%CI) in the random-effects model using DerSimonian and Laird's estimator. Results: Three studies involving 637 patients were included. Based on the random effects model performed in two included studies of 237 patients, the association between PZQ treatments and CCA was not statistical significant with a pooled OR of 1.8 (95%CI; 0.81 to 4.16). Conclusions: The present systematic review and meta-analysis provides inconclusive evidence of risk effect of PZQ on increasing the risk of CCA and significant methodological limitations. Further research is urgently needed to address the shortcomings found in this review, especially the requirement for histological confirmation.

• Parasites, Hosts and Diseases
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• v.49 no.1
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• pp.45-49
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• 2011

Chemotherapy of clonorchiasis with praziquantel (PZQ) is effective but about 15% of treated cases have been reported uncured. The present study investigated correlation of single nucleotide polymorphisms (SNPs) of the cytochrome P450 gene, CYP3A5 and cure of clonorchiasis. A total of 346 egg passing residents were subjected and treated by 3 doses of 25 mg/kg PZQ. Reexamination recognized 33 (9.5%) uncured and 313 cured. Numbers of eggs per gram of feces (EPGs) before treatment were significantly lower in the cured group than in the uncured group ($2,011.2{\pm}3,600.0$ vs $4,998.5{\pm}7,012.0$, P<0.001). DNAs of the subjects were screened for SNPs at 7 locations of CYP3A5 using PCR. In the uncured group, the SNP frequencies at g.-20555G > A and g.27526C > T of CYP3A5 were 15.2% and 9.1% while those were 3.8% and 1.0%, respectively, in the cured group. The cure rate was Significantly lower in the cases with SNP at g.27526C > T and EPGs ${\geq}$ 1,000. In conclusion, EPGs and SNPs of CYP3A5 are factors which influence cure of clonorchiasis by PZQ therapy. It is strongly suggested to recommend 2-day medication for individuals with high EPGs ${\geq}$ 1,000.

• Parasites, Hosts and Diseases
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• v.32 no.1
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• pp.35-42
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• 1994

This study was designed to evaluate the humoral immune reactions in clonorchiasis before and after praziquantel treatment. Rabbits were infected with 150 or 450 metacercariae, treated on 4 and 8111 months after infection, and observed for 13 months of posttreatment. Infection controls were maintained for 22 months. Antigen was the metabolic product of worms incubated in physiologic saline. The immune reactions of anti-clonorchis IgG were observed using SDS-PAGE/immunoblot. During the Infection and Posttreatment, the antigenic Proteins of 66, 63, 54, 52, 50,47,42, 40, 38, 34,33,30, 27, 25, 23, 20, 19, 18, 17, 16, 15, 14, 13, 12.5 and 11.5 kDa were detected. Of them, 33,27, 13, and 12.5-kDa antigens were highly antigenic and observed predominently in infection controls. After the treatment, 13 and 12.5-kDa antigens faded in 6 months after the second treatment, but 33 and 27-kDa antigens were detected until 13 months of posttreatment. The results clearly demonstrate that 13 and 12.5-kDa antigens represent attenuated host immune reactions by praziquantel treatment. As the 12.5-kDa antigen had a large amount of protein in SDS-PAGE, it was designated as'K2-Ag'of C. sinenis.

• Parasites, Hosts and Diseases
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• v.44 no.4 s.140
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• pp.361-366
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• 2006

Sustained-releasing praziquantel (SRP) tablet was designed for single dose treatment regimen of clonorchiasis. A previous pre-clinical study confirmed its sustained-releasing characteristics and a better cure rate than conventional praziquantel (PZQ). In this clinical study, the pharmacokinetics of this SRP tablet were investigated in human volunteers (phase 1; 12 volunteers), and its curative efficacy was examined in clonorchiasis patients (phase 2; 20 volunteers). In the phase 1 clinical study, blood concentrations of both tablets showed wide individual variation. The $AUC_{last}$ of SRP was $497.9{\pm}519.0ng{\cdot}hr/ml\;(mean{\pm}SD)$ and PZQ of $628.6{\pm}695.5\;ng{\cdot}hr/ml$, and the $AUC_{inf}$ of SRP was $776.0{\pm}538.5\;ng{\cdot}hr/ml$ and of PZQ $658.6{\pm}709.9\;ng{\cdot}hr/ml$. $C_{max}$ values of SRP and PZQ were $90.7{\pm}82.2ng/ml\;and\;214.9{\pm}251.9\;ng/ml$, and $T_{max}$ values were $3.42{\pm}1.43\;hr\;and\;1.96{\pm}1.23\;hr$, respectively. SRP tablets showed similar AUC values, but lower $C_{max}$ and longer $T_{max}$ values than PZQ. In the phase 2 study, SRP at 30 mg/kg (single dose) achieved a 60% cure rate and a 95.5% egg reduction rate. The cure rate of a single dose SRP was unsatisfactory compared with that of the conventional PZQ dose, but much better than that achieved by a single dose PZQ.