• Parasites, Hosts and Diseases
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• v.56 no.1
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• pp.75-79
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• 2018

Adult specimens of Echinostoma ilocanum (Garrison, 1908) Odhner, 1911 (Trematoda: Echinostomatidae) were recovered from 2 riparian people who resided along the Mekong River in Savannakhet Province, Lao PDR. In fecal examinations done by the Kato-Katz technique, they revealed echinostome eggs together with eggs of Opisthorchis viverrini (and minute intestinal fluke eggs) and hookworms. To recover the adult flukes, they were treated with praziquantel 30-40 mg/kg in a single dose and purged with magnesium salts. A total of 658 adult fluke specimens were recovered from the 2 people; 456 from case 1 and 202 from case 2. Specimens from case 1 consisted of 335 echinostomes (301 E. ilocanum and 34 species undetermined), 120 O. viverrini, and 1 Haplorchis taichui, and those from case 2 consisted of 36 E. ilocanum, 134 O. viverrini, and 32 H. taichui. Thus, the number of E. ilocanum specimens was 337 in total (average per person, 168.5). From this study, it is suggested that foodborne intestinal flukes and liver flukes are highly prevalent along the Mekong River in Savannakhet Province. The present report describes for the first time human infections with E. ilocanum in Lao PDR.

• Parasites, Hosts and Diseases
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• v.26 no.2
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• pp.127-132
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• 1988

Two adult specimens of heterophyid cuke, which belong to the genus Stictodora, were collected from the stool of a 24-year old man after chemotherapy. The nukes were morphologically characterized by their small body siRe (0.90~0.98mm long and 0.38 mm wide) and peculiar structure of ventrogenital sac with armed gonotyl (with about 12~I5 spines) not enveloping genital pore. Species identification is deferred until more worms are obtained, although they closely resemble Stictadora fuscatum (Onji and Nishio, 1916). The Patient used to eat raw flesh of mullets and gobies, which are regarded as the infection source of Stictodora sp., together with 3 other kinds of heterophyids described elsewhere. This is the first record of human Stictodora infection in the literature.

• Parasites, Hosts and Diseases
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• v.59 no.3
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• pp.189-225
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• 2021

The use of albendazole and mebendazole, i.e., benzimidazole broad-spectrum anthelmintics, in treatment of parasitic infections, as well as cancers, is briefly reviewed. These drugs are known to block the microtubule systems of parasites and mammalian cells leading to inhibition of glucose uptake and transport and finally cell death. Eventually they exhibit ovicidal, larvicidal, and vermicidal effects on parasites, and tumoricidal effects on hosts. Albendazole and mebendazole are most frequently prescribed for treatment of intestinal nematode infections (ascariasis, hookworm infections, trichuriasis, strongyloidiasis, and enterobiasis) and can also be used for intestinal tapeworm infections (taeniases and hymenolepiasis). However, these drugs also exhibit considerable therapeutic effects against tissue nematode/cestode infections (visceral, ocular, neural, and cutaneous larva migrans, anisakiasis, trichinosis, hepatic and intestinal capillariasis, angiostrongyliasis, gnathostomiasis, gongylonemiasis, thelaziasis, dracunculiasis, cerebral and subcutaneous cysticercosis, and echinococcosis). Albendazole is also used for treatment of filarial infections (lymphatic filariasis, onchocerciasis, loiasis, mansonellosis, and dirofilariasis) alone or in combination with other drugs, such as ivermectin or diethylcarbamazine. Albendazole was tried even for treatment of trematode (fascioliasis, clonorchiasis, opisthorchiasis, and intestinal fluke infections) and protozoan infections (giardiasis, vaginal trichomoniasis, cryptosporidiosis, and microsporidiosis). These drugs are generally safe with few side effects; however, when they are used for prolonged time (>14-28 days) or even only 1 time, liver toxicity and other side reactions may occur. In hookworms, Trichuris trichiura, possibly Ascaris lumbricoides, Wuchereria bancrofti, and Giardia sp., there are emerging issues of drug resistance. It is of particular note that albendazole and mebendazole have been repositioned as promising anti-cancer drugs. These drugs have been shown to be active in vitro and in vivo (animals) against liver, lung, ovary, prostate, colorectal, breast, head and neck cancers, and melanoma. Two clinical reports for albendazole and 2 case reports for mebendazole have revealed promising effects of these drugs in human patients having variable types of cancers. However, because of the toxicity of albendazole, for example, neutropenia due to myelosuppression, if high doses are used for a prolonged time, mebendazole is currently more popularly used than albendazole in anti-cancer clinical trials.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4285-4288
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• 2012

Background: Opisthorchis viverrini infection is a serious public-health problem in Southeast Asia. It is associated with a number of hepatobiliary diseases and the evidence strongly indicates that liver fluke infection is the etiology of cholangiocarcinoma. Objectives: This study aimed to determine Opisthorchis viverrini infection in elderly people in Surin province, Northeastern Thailand. Methods: A community-based cross-sectional survey was conducted among 333 elderly in 17 districts of Surin province, during one year period from January to December 2011. O. viverrini infection was determined using Kato's Thick Smear technique and socio-demographic were collected using predesigned semi-structured questionnaires, respectively. Results: A total of 333 elderly including 116 males and 217 females were selected from different study sites. Overall intestinal parasitic infection was 16.2%, predominantly in O. viverrini (9.91%) and followed by Strongyloides stercolaris (4.80%) and hookworm (1.50%), respectively. The O. viverrini infection was found higher in males (13.8%) than females (7.83%), and frequently in elderly 60-70 year old with 14.2%. Chi-square testing indicated that education and occupation were significantly associated with O. viverrini infection (P value = 0.02). The distribution of O. viverrini infection was found in 11 districts which was covered 64.7% of the studies areas. The highest prevalence was found in Thatum with 39.1%, and followed by Sangkha (24.0%), Buachet (21.1%), Samrong Thap (19.1%), Si Narong (15.0%), and Ratanaburi (13.3%) districts. Conclusion: This findings stress that O viverrini is still a problem in Thailand. We confirmed, for the first time, the high endemicity of human O. viverrini infections in elderly in Surin province of Thailand, underlying the fact that mass treatment and health education are urgently required.

• Parasites, Hosts and Diseases
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• v.50 no.3
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• pp.207-213
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• 2012

The egg morphology of minute intestinal flukes (MIF) that can occur as human infections in the Republic of Korea, i.e., Metagonimus yokogawai, M. miyatai, M. takahashii, Heterophyes nocens, Heterophyopsis continua, Stellantchasmus falcatus, Stictodora fuscata, Pygidiopsis summa, and Gymnophalloides seoi, was studied in comparison with Clonorchis sinensis. The adult worms were obtained from residents of endemic areas, and their intrauterine eggs were studied and measured using light microscopy; the length, width, length-width ratio (LWR), and Faust-Meleney index (FMI). Several specimens were processed for scanning electron microscopy (SEM), and before gold-coating, the uterine portion of each fluke was etched with a sharp pin in order to expose the eggs. The MIF eggs were ovoid, pyriform, or elliptical with a size range of $21-35{\times}12-21{\mu}m$. S. fuscata eggs revealed the highest FMI (largest in the area) and lowest LWR, whereas P. summa eggs showed the lowest FMI and medium LWR. SEM revealed that G. seoi and S. fuscata had remarkably clean shell surface lacking the muskmelon-like structure which is prominent in C. sinensis eggs. In Metagonimus spp., H. continua, H. nocens, and S. falcatus eggs, minute surface ridges were recognizable though less prominent compared with C. sinensis. On the surface of P. summa eggs, thread-like curly structures were characteristically seen. The results revealed that important differential keys for MIF eggs include the length, width, area (FMI), shape of the eggs, and the extent of the muskmelon-like structure or ridges on their shell surface and operculum.

• Parasites, Hosts and Diseases
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• v.39 no.2
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• pp.85-118
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• 2001

Studies on Gymnophalloides seoi (Digenea: Gymnophallidae) and human infections are briefly reviewed. This minute intestinal fluke was first discovered from a Korean woman suffering from acute pancreatitis and gastrointestinal troubles. It was described as a new species by Lee, Chai and Hong in 1993. The southwestern coastal village where the patient resided was found to be a highly endemic area, and additional endemic areas have been identified. The parasite is very small, 0.33-0.50 mm long and 0.23-0.33 mm wide. and characterized by the presence of a ventral pit. The first intermediate host remains unknown, but the second intermediate host has been found to be the oyster Crassostrea gigas. Man and the Palearctic oystercatcher Haematopus ostralegus have been shown to be natural definitive hosts , and wading birds including the Dentish plover Charadrius alexandrinus are highly susceptible to experimental infection. Gerbils, hamsters, cats, and several strains of mice were also susceptible laboratory hosts. In experimentally infected mice, the parasites inhabit the small intestine, pinching and sucking the root of villi with their large oral suckers, but they did not invade beyond the mucosa in immunocompetent mice. However, they were found to invade the submucosa in immunosuppressed mice. Human G. seoi infections have been found in at least 25 localities; 23 islands on the Yellow Sea or the South Sea, and 2 western coastal villages. The highest Prevalence was found in a village on Aphaedo. Shinan-fun (49% e99 Positive rate) : other areas showed 0.8-25.3% prevalence. Infected people complained of variable degrees of gastrointestinal troubles and indigestion. The infection can be diagnosed by recovery of eggs in the feces; however, an expert is needed to identify the eggs. Praziquantel, 10mg/kg in single dose, is effective for treatment of human infections. Eating raw oysters in endemic areas should be avoided.

• Parasites, Hosts and Diseases
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• v.44 no.1 s.137
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• pp.87-89
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• 2006

A 55-year old Korean man, living in Mokpo-city, Jeollanam-do, Republic of Korea, visited a local clinic complaining of right upper quadrant pain and indigestion. At colonoscopy, he was diagnosed as having a carcinoma of the ascending colon, and thus, a palliative right hemicolectomy was performed. Subsequently, an adult fluke of Gymnophalloides seoi was incidentally found in a surgical pathology specimen of the lymph node around the colon. The worm was found to have invaded gut lymphoid tissue, with characteristic morphologies of a large oral sucker, a small ventral sucker, and a ventral pit surrounded by strong muscle fibers. This is the first reported case of mucosal tissue invasion by G. seoi in the human intestinal tract.

• Parasites, Hosts and Diseases
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• v.50 no.3
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• pp.215-220
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• 2012

The source of human infection with intestinal flukes was surveyed in estuarine fishes, including the dotted gizzard shad, common sea bass, common blackish goby, redlip mullet, black sea bream, and oyster collected from Muan-gun, Jeollanam-do, Korea during August and September 2007. Collected fishes and oysters were artificially digested in pepsin-HCl solution and examined under a stereomicroscope. In 36 shads (Konosirus punctatus) and 20 basses (Lateolabrax japonicus) examined, Heterophyopsis continua metacercariae were found in 58.3% and 100%, and their average numbers were 12.0 and 6.3 per infected fish, respectively. In 34 gobies (Acanthogobius flavimanus) examined, metacercariae of H. continua were detected in 79.4%, Stictodora lari in 97.1%, and Acanthotrema felis in 92.1%, and their average numbers were 45.8, 189.3, and 235.3 per infected fish, respectively. In 37 redlip mullets (Chelon haematocheilus), Heterophyes nocens metacercariae were found in 56.8%, Pygidiopsis summa in 94.6%, and Stictodora fuscata in 45.9%, and the average metacercarial densities were 17.4, 31.3, and 35.1 per infected fish, respectively. In 30 black sea breams (Acanthopagrus schlegeli) and 45 oysters (Crassostrea gigas) examined, no metacercariae were detected. From the above results, it has been confirmed that the dotted gizzard shad, common sea bass, common blackish goby, and redlip mullet from Muan-gun, Jeollanam-do, Korea are infected with the metacercariae of heterophyid flukes.

• Parasites, Hosts and Diseases
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• v.33 no.1
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• pp.1-8
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• 1995

Gymnophalkides seoi has drawn medical attentions since the discovery of the first human case and a highly endemic area on a southwestern coastal island of Shinan- gun, Korea. Marine bivalves especially oysters were strongly suspected as the source of infection. In this study the oysters, Crassostrea girns, naturally produced (rom the endemic area were examined whether they contain gymnophallid metacercariae. All of 50 oysters examined were infected with the metacercaviae of a gymnophallid, with the metacercarial density per oyster of 610 on average (2-4,792 in range). Later they were identified as G. seoi by obtaining adult worms from experimental mice. The metacercariae were unencysted, and firmly attached on the mantle surface of the oysters with their oral sucker. In sectioned specimens they were equipped with the ventral pit, a peculiar organ of the genus Gymophalloides, and non-muscular genital pore which was connected dorsally to the seminal vesicle. The seminal vesicle was in a great majority mono-sac. By this study, it has been confirmed that the oyster is a 2nd intermediate host of G. seoi as well as the major source of human infection with this fluke.

• Parasites, Hosts and Diseases
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• v.23 no.2
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• pp.214-220
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• 1985

Four cases of human infection by Echinochasmus japonicus (Trematoda; Echinostomatidae) were proven by the recovery of adult worms after a treatment with praziquantel (10mg/kg in single dose) and purgation in February 1984 in Korea. The patients were 3 middle-aged men and 1 elderly woman residing in a riverside village of Kangjin-gun (Tamjin river), Jeonranam-do, an ever-known endemic area of metagonimiasis. The treatment revealed numerous M. yokogawai worms together with 1-43 (total 54) specimens of E. japonicus and/or a few number of other kinds of trematodes or cestodes. The patients had gastrointestinal troubles such as indigestion and abdominal discomfort, probably due to these fluke infections. They have been eating some raw flesh of fresh water fishes such as cyprinoid ones or sweet fish caught from the river. This is the first record of human E. japonicus infection in the literature.