study on the surface morphology of the developmental stages of the liver fluke, opisthorchis viverrini (trematoda: opisthorchiidae).the external morphology of some developmental stages of the fluke opisthorchis viverrini (trematoda: opisthorchiidae), parasitizing humans in southeast asia was studied for the first time using electron microscopy. the surface structure of the egg, as well as the rediae, cercaria, metacercaria, and adult found in naturally infected hosts from laos are described herein and their morphological characteristics discussed.19921290379
detection of opisthorchis viverrini antigens in stools using specific monoclonal antibody.detection of opisthorchis viverrini antigens in stools using specific monoclonal antibody. international journal for parasitology 22: 527-531. a sandwich enzyme-linked immunosorbent assay (elisa) was developed for detecting opisthorchis viverrini antigen in faecal extracts of four groups of individuals. these were 24 patients with o. viverrini infection only (group 1), 31 patients with o. viverrini and other parasitic infections (group 2), 141 patients with other parasitic infections (group 3) a ...19921644529
comparative morphology of eggs of the haplorchiinae (trematoda: heterophyidae) and some other medically important heterophyid and opisthorchiid flukes.the egg morphology of the following medically important small flukes from southeast asia and far east were studied: opisthorchis viverrini, clonorchis sinensis (opisthorchiidae), haplorchis taichui, h. pumilio, h. yokogawai, stellantchasmus falcatus and metagonimus sp. (heterophydiae). this study revealed a great intraspecific variability and interspecific similarity in size and shape of eggs. the eggs shape does not seem to be suitable for species identification. on the other hand, biometrical ...19921644359
repeated exposure to opisthorchis viverrini and treatment with the antihelminthic praziquantel lacks carcinogenic potential.the effects of repeated praziquantel administration, subsequent to infection and reinfection with opisthorchis viverrini (ov), on lesion development in the syrian hamster liver were investigated. five applications of the antihelminthic drug were made (300 mg/kg body wt, i.g.), each time approximately 5 weeks after dosing with 60-80 ov metacercariae at weeks 0, 8, 16, 24 and 32. the animals were then maintained until week 40 when they were killed; histopathological investigation revealed no signi ...19921740024
larval stages of medically important flukes (trematoda) from vientiane province, laos. part ii. cercariae.the cercariae of five flukes, which are potential human parasites, opisthorchis viverrini (family opisthorchiidae), haplorchis taichui (heterophyidae), schistosoma spindale (schistosomatidae), fasciolopsis buski, and fasciola gigantica (fasciolidae) were found in freshwater snails from laos. the cercariae of the above species, recorded in laos for the first time, are illustrated and their morphology is briefly described. the snail helicorbis umbilicalis represents a new intermediate host of f. b ...19921290378
prevalence and intensity of opisthorchis viverrini in rural community near the mekong river on the thai-laos border in northeast thailand.the prevalence and intensity of opisthorchis viverrini in fourteen villages in nakhon-phanom province, northeast, thailand have been investigated. overall prevalence of o. viverrini infection was 66.4 per cent in a total population of 2,412 individuals. the prevalence was 18.5 per cent in children under 5 years, 38.9 per cent in those aged 5-9 years, and ranged from 64.9 per cent to 82.2 per cent in the age group above 10 years. the intensity of o. viverrini infection increased with age. the mea ...19921402447
effects of the injectable contraceptive depot medroxyprogesterone acetate in thai women with liver fluke infestation: results after six months.the effect of the three-monthly injectable contraceptive depot medroxyprogesterone acetate (dmpa) on liver and lipid function was assessed in thai women with liver fluke (opisthorchis viverrini) infestation, dmpa administration being started in the immediate postpartum period. immediate postpartum iud and sterilization acceptors with fluke infestation were recruited as a comparison (control) group for the fluke-positiv dmpa acceptors. comparable groups of fluke-negative acceptors were recruited ...1977302157
development of immune-complex glomerulonephritis and amyloidosis in syrian golden hamsters infected with opisthorchis viverrini.renal disease associated with opisthorchis viverrini infection was investigated in syrian golden hamsters. on the fourth week after infection with 100 viable metacercariae; anti-tegumental membrane antibodies were detected in the sera by immunofluorescence antibody technic and by enzyme-linked immunosorbent assay. six weeks after infection tegumental and anti-tegumental membrane immune-complex and amyloid fibrils were found in the glomeruli. amyloid was characterized to be aa protein. acute prol ...19921402485
liver changes in hamsters infected with a liver fluke of man, opisthorchis viverrini.thirty male syrian golden hamsters were each infected with 100 metacercariae of opisthorchis viverrini. the hamsters were killed at 3, 7, 15, 30, 154 days of infection. the early pathological changes consisted of an acute inflammatory reaction involving the bile ducts of the second order and the portal connective tissue, especially the large veins, as well as focal coagulation necrosis of the liver lobules. as the flukes developed into adults they induced hyperplasia and adenomatous formations o ...1978686245
separation and characterization of adult worm proteins and glycoproteins from the liver fluke opisthorchis viverrini.detailed studies of liver fluke proteins and antigens are necessary to facilitate further investigation of the human immune responses to these parasites. accordingly, opisthorchis viverrini antigens were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (sds-page) and immunoblotting. we initially encountered excessive background smearing, vertical streaking, and indistinct bands that were similar to problems previously described by investigators studying this and other tremat ...19921635026
effects of dimethylnitrosamine on induction of cholangiocarcinoma in opisthorchis viverrini-infected syrian golden hamsters. 1978214229
endogenous nitrosamines and liver fluke as risk factors for cholangiocarcinoma in thailand.cholangiocarcinoma (cca) is one of the most prevalent cancers in north-east thailand and has been associated with infestation by the liver fluke opisthorchis viverrini (ov). two samples of 12-h overnight urine (after dosing with 500 mg proline and 200 mg ascorbic acid or 500 mg proline alone) were collected from about 100 inhabitants in five contrasting incidence areas for cca and hepatocellular carcinoma. the incidences of cca and hepatocellular carcinoma were not correlated with either the amo ...19911649794
liver cancer in thailand. i. a case-control study of cholangiocarcinoma.potential risk factors for cholangiocarcinoma were investigated in a case-control study among inhabitants of north-east thailand, which included 103 cases from 3 hospitals, with age- and sex-matched controls. a clear association with past or present infection with opisthorchis viverrini, as indicated by raised serum antibodies, was found (o.r. 5.0), and at least two-thirds of cases can be attributed to this cause. the results suggest that males may be at higher risk than females. there was no as ...19911645697
multistage carcinogenesis of liver-fluke-associated cholangiocarcinoma in northeast thailand, the traditional habit of eating ground, raw freshwater and salt-fermented fish on a daily basis results in a local population repeatedly exposed to both liver fluke (opisthorchis viverrini) infection and consuming nitrosamine-contaminated food from early in life. epidemiological studies have revealed a coincident high prevalence of cholangiocarcinoma in this region and we have demonstrated in animal models that dietary contamination with nitrosamines and opisthorchiasis ar ...19911668894
opisthorchis viverrini infestation and endogenous nitrosamines as risk factors for cholangiocarcinoma in thailand.cholangiocarcinoma (cca) is one of the most common cancers in north-east thailand and has been associated with infestation by the liver fluke opisthorchis viverrini (ov). two samples of 12-hr overnight urine (after dosing with proline and ascorbic acid or proline alone) were collected from 20 inhabitants from each of 5 contrasting incidence areas for cca. the incidence of cca was not correlated with either the amount of npro or other nitrosamino acids, endogenous nitrosation potential (differenc ...19911650329
production and characterization of monoclonal antibodies against the excretory-secretory antigen of the liver fluke (opisthorchis viverrini).monoclonal antibodies (moab) were produced against a major soluble metabolic product (excretory-secretory, es) of opisthorchis viverrini. the latter was obtained in a form of spent culture medium in which the adult flukes had been maintained in vitro. the moab produced were exclusively associated with either igg or igm isotypes. when screened against a panel of parasite antigens by indirect elisa, these moab exhibited three patterns of reactivity. approximately 50% of the moab were highly specif ...19911717391
relationship between intensity of opisthorchis viverrini infection and hepatobiliary disease detected by ultrasonography.twenty-four locality-, age- and sex-matched groups of village residents with no light, moderate and heavy opisthorchis viverrini infection were examined by ultrasonography. highly significant differences were observed between the groups in the relative size of the left lobe of the liver and the fasting and post-meal size of the gall-bladder. in addition, indistinct gall-bladder wall, the presence of gall-bladder sludge and strongly enhanced portal vein radicle echoes were most frequently observe ...19921311966
control of opisthorchis viverrini cercariae using the copepod mesocyclops leuckarti. 19921439992
malacological survey in the sirikit reservoir, the largest earthfilled dam in thailand.ten species of freshwater molluscs were found in a malacological survey in the sirikit reservoir in 1985. among these species, tricula aperta or neotricula aperta, intermediate host of human schistosomes, bithynia (digoniostoma) siamensis goniomphalos and b. (d.) funiculata, the first intermediate host of opisthorchis viverrini were not found. it is revealed that most of the habitats in the sirikit reservoir are not suitable for the survival and colonization of molluscs. thus few species of edib ...19921439988
quantitative post-mortem study of opisthorchis viverrini in man in north-east thailand.the results of an autopsy study of opisthorchis viverrini infection in 181 accident subjects in northeast thailand are presented. the age-prevalence profiles were similar whether determined by faecal examination for parasite eggs or by recovery of worms from the liver. the prevalence increased rapidly with age and reached a plateau at 70-80% in adults. the overall prevalence estimated by faecal examination was 69.2%, while that measured by worm recovery was 79.2%. the average intensity of infect ...19911801350
cloning and characterization of ribosomal rna genes from opisthorchis viverrini.the ribosomal dna (rdna) unit of the liver fluke opisthorchis viverrini has been cloned and characterized. the results demonstrated that the total length of this unit is approximately 13 kb, containing 4.2 kb of large subunit (lsu) rdna, 2.0 kb of small subunit (ssu) rdna, 1.0 kb of transcribed spacer dna and 5.8 kb of non-transcribed + external transcribed spacer dna. examination of the non-transcribed spacer region between different rdna units showed variation in the restriction sites rather t ...19921594296
cholangiocarcinomas in japanese and thai patients: difference in etiology and incidence of point mutation of the c-ki-ras proto-oncogene.point-mutational activation of the c-ki-ras proto-oncogene has been shown to be rare in human hepatocellular carcinoma, the most common primary liver cancer and one usually associated with chronic viral infection. to reveal the association of c-ki-ras activation with cholangiocarcinogenesis under different etiological backgrounds, the incidence of point mutation at codons 12 and 13 of the c-ki-ras proto-oncogene was examined in three groups of human liver cancers with differentiation to biliary ...19921336666
histomorphological characteristics of cholangiocellular carcinomas in northeast thailand, where a region infection with the liver fluke, opisthorchis viverrini is endemic.northeast thailand has a very high incidence rate of intrahepatic biliary tumors which is believed to closely related to infestation with the liver fluke, opisthorchis viverrini. this study was conducted to ascertain whether there are any phenotypic differences in such tumors between northeast thailand and japan, a country free of liver flukes. forty one intrahepatic cholangiocarcinomas from patients in northeast thailand were histopathologically compared with 39 lesions collected in japan. the ...19921334615
occurrence of some medically important flukes (trematoda: opisthorchiidae and heterophyidae) in nam ngum water reservoir, laos.occurrence of some medically important flukes transmitted to man by eating of raw fish was observed at 18 localities of nam ngum water reservoir, an important source of fish for inhabitants of vientiane province, laos. cercariae of opisthorchis viverrini were recorded in 0.9% of bithynia siamensis goniomphalus examined but in the most populated sites, where the density of the snails was the highest up to 2.2% of the intermediate hosts were infected. haplorchis cercariae were found in 2.0% of tar ...19902075492
specific and cross-reactive monoclonal antibodies to the 89-kda antigen of opisthorchis viverrini. 19921283231
a histopathologic study of 61 cases of peripheral intrahepatic cholangiocarcinoma.the histopathological study of 61 cases of peripheral intrahepatic cholangiocarcinoma was reported. of the 5 autopsied livers and 13 surgically resected livers, 89 per cent showed massive gross appearance, 94 per cent contained opisthorchis viverrini or showed evidence of previous opisthorchiasis. gall stones were found in 7 cases (11.5%), common bile duct stones were found in one case. the tumors were classified into well differentiated, less differentiated and uncommon types (adenosquamous, an ...19911665850
specific monoclonal antibodies to opisthorchis viverrini.a balb/c mouse was immunized with a crude soluble antigen of opisthorchis viverrini adult worms (ovaa) over a period of 7 months. spleen cells from the immune mouse were fused with sp2/0 myeloma cells. among the 264 tissue culture wells containing the fused cells, cells of 96 wells (36%) produced antibodies to the immunizing agent. antibodies produced by cells in several wells reacted with antigens from other species of parasite. cells of 17 wells produced antibodies specific only to ovaa, thus ...19911787041
the role of infection by opisthorchis viverrini, hepatitis b virus, and aflatoxin exposure in the etiology of liver cancer in thailand. a correlation study.the incidence of the two principle types of liver cancer (hepatocellular carcinoma and cholangiocarcinoma) in five different areas of thailand was compared with the prevalence of exposure to the main risk factors in samples of the population. cholangiocarcinoma showed striking variations in incidence, which correlated closely with markers of exposure to the liver fluke, opisthorchis viverrini. however, there was little geographic variation in incidence of hepatocellular carcinoma or in prevalenc ...19911657355
possible effect of infection with liver fluke (opisthorchis viverrini) on the monitoring of urine by enzyme-linked immunosorbent assay for human exposure to aflatoxins.several laboratories have initiated studies to assess human exposure to aflatoxin at an individual level by measuring aflatoxin metabolites in the urine by immunoassay. the fact that the antibodies recognize a variety of metabolites, albeit with differing affinities, means that any environmental factor that modifies the pattern of urinary metabolites associated with a given exposure could affect quantification in immunoassay. we have examined two such possible effects: (i) the pattern of metabol ...19911855928
human opisthorchis and haplorchis infections in laos.a study of the epidemiology of trematode infections was carried out in vientiane province, laos, comprising examination of snails, fish, cats, and human stools. opisthorchis viverrini cercariae were found in the snail bithynia siamensis goniomphalus (bithyniidae) and haplorchis taichui cercariae in tarebia granifera (thiaridae). o. viverrini metacercariae were recorded in the flesh of 7 species of cyprinid fish; metacercariae of the heterophyid fluke haplorchis taichui were found in 4 species of ...19911755066
socio-economic, health and nutritional status of the villagers in the nong wai irrigation area, khon kaen, northeast thailand.studies were carried out from june 1974 to may 1975 on the socio-economic status, health and nutritional status of the people in 4 villages, in the irrigation area of the nong wai pioneer agricultural project of khon kaen province, northeast thailand. the result obtained were compared with those in 2 non-irrigated villages in the same province, in order to identify the health and nutritional problems which might arise during the water resource development in the irrigation area. it was found tha ...19761030856
eggshell morphology of the small eggs of human trematodes in thailand.light and scanning electron micrographs of opisthorchis viverrini, haplorchis taichui, h. pumilio, a phaneropsolus bonnei, and prosthodendrium molenkampi eggs were studied. under light microscopy. o. viverrini eggs had rough eggshells and prominent shoulders. h. taichui, h. pumilio were similar in shape and had smooth eggshells and prominent shoulders. h. pumilio eggs were bigger than h. taichui eggs. p. bonnei and p. molenkampi eggs had smooth eggshells and indistinct shoulders. p. bonnei eggs ...19911820654
comparative studies on the morphology of the eggs of opisthorchis viverrini and lecithodendriid trematodes.iodine staining and scanning electron microscopy were used to determine the morphological features distinguishing opisthorchis viverrini from lecithodendriid eggs in human feces. the embryonated eggs of lecithodendriid trematodes differ from o. viverrini by the presence of an iodophilic body, a large mass at the posterior end of miracidium that stains brown in 0.2% iodine solution and the curved miracidium of phaneropsolus bonnei. all forms of lecithodendriid eggs can be differentiated from thos ...19911820653
penetration of stimuli of fish skin for acanthostomum brauni cercariae.the cercaria of acanthostomum brauni penetrates the skin of its fish host in response to a combination of two chemical signals from the fish skin surface: free fatty acids and a macro-molecular mucus component. the latter seems to be a protein, as the penetration-stimulating activity of fish skin surface mucus is eliminated by digestion with proteinase, but not by digestion with glycosidases, nor by a removal of glycosaminoglycans. these penetration-stimulating host signals differ from the glyco ...19911903874
molecular analysis of t and b cell repertoires in mice immunized with opisthorchis viverrini antigens.b10 mice were immunized with an opisthorchis viverrini somatic extract and then their responses were analyzed. the antigenic fractions of the extract were separated by sds-polyacrylamide gel electrophoresis, electroblotted to nitrocellulose membranes and solubilized for use in lymphocyte culture. antibody specificity was also visualized by immunoblotting using immunized mouse sera. the mr of the main immunogenic fractions for t cells ranged from 28 to 46 kda, whereas those recognized by antibodi ...19911757200
preliminary estimates of economic impact of liver fluke infection in thailand and the feasibility of irradiation as a control measure.liver fluke infection by opisthorchis viverrini is the leading cause of food-borne parasitic disease in thailand. approximately one third of the population in the northeastern region of the country, ie, 6-7 million, are infected by this parasite through the habit of consuming raw or insufficiently cooked freshwater fish, especially those of cyprinoid family. a recent survey showed that 60% of the work force in the northeast between the age of 15 and 60 is infected. the estimated wage loss of thi ...19911822933
current status of food-borne parasitic zoonoses in laos.stool samples from a total of 1,008 persons were examined for intestinal parasites during a comprehensive study on the epidemiology of small fluke infections in laos. the prevalence of small fluke eggs in the stool was seen to peak at age 20 years, particularly in men from villages (90.4%). three quarters of infections belong to the category of light infections and only 0.6% to the category of very heavy according to eggs per gram of feces (epg). the highest epg was in the 11-15 year age group. ...19911822938
detection of shared antigens of human liver flukes opisthorchis viverrini and its snail host, bithynia spp.the relationship between opisthorchis viverrini and its snail intermediate host including bithynia funiculata, b. siamensis siamensis and b. siamensis goniomphalos was carried out on the correlation of shared antigens and infection rates. b. funiculata and b. s. siamensis were equally susceptible to o. viverrini with relatively high infection rates of 72.2% and 69.9% respectively whereas b. s. goniomphalos gave lowest percentage of infection of only 9.6%. by immunoelectrophoresis, crude extract ...19902075387
serological differentiation of human small fluke infections using opisthorchis viverrini and haplorchis taichui antigens.sera from 642 inhabitants of vientiane province (laos) were examined by enzyme-linked immunosorbent assay (elisa) using cytoplasmic and membranous antigens prepared from adult worms. worms of opisthorchis viverrini originated from liver of dissected cats, haplorchis taichui were obtained from a stool specimen of a laotian patient after praziquantel treatment. the sera were divided into five groups according to the intensity of infection expressed as egg count per gram of patients stool (epg). co ...19911822881
immunodiagnosis of opisthorchiasis.monoclonal antibody-based enzyme-linked immunosorbent assay and dna dot blot hybridization techniques were developed and evaluated for their potential in the detection of opisthorchis viverrini. a mixture of igg monoclonal antibodies specific for the 89 kda metabolic product of o. viverrini was captured on a microtiter plate by rabbit anti-mouse igg and used in a sandwich elisa for the detection of soluble parasite antigen in the feces of patients with opisthorchiasis. as little as 0.1 ng of the ...19911822882
opisthorchis viverrini: relationships between egg counts, worms recovered and antibody levels within an endemic community in northeast thailand.three techniques for estimating the intensity of opisthorchis viverrini infection in individuals from a northeast thai community are compared. egg counts were determined using a quantitative formalin/ethyl acetate technique, worm burdens were estimated by expulsion chemotherapy and antibody levels were measured by elisa. log-transformed worm and egg counts were closely correlated (r = 0.80), suggesting that both measurements provide good assessments of relative intensity of infection. however, n ...19911852494
serum unconjugated primary and secondary bile acids in patients with cholangiocarcinoma and hepatocellular carcinoma.serum unconjugated primary bile acids (cholic acid, chenodeoxycholic acid), secondary bile acids (lithocholic acid, deoxycholic acid), conjugated primary bile acids (glycocholic acid, glycohenodeoxycholic acid, taurocholic acid, taurochenodeoxycholic acid) and total bile acids were measured in 25 and 75 male patients with cholangiocarcinoma and hepatocellular carcinoma respectively. twenty-one healthy male volunteers served as controls. other biochemical parameters, i.e. bilirubin, transaminases ...19902161896
relationship between faecal egg count and worm burden of opisthorchis viverrini in human autopsy cases.the relationship between faecal examination for egg output and worm burden of opisthorchis viverrini in man of 181 autopsy cases from northeast thailand is described. diagnosis of the parasite infection by stool examination for the presence of eggs was less sensitive than the worm recovery technique. using stoll's dilution and formalin-ether technique, no eggs were detected in the faeces of 20 cases harbouring low worm burdens (less than 20 worms). the quantitative faecal egg count by stoll's di ...19911852493
isolation and characterization of opisthorchis viverrini specific dna opisthorchis viverrini specific repetitive dna fragment was isolated from the o. viverrini genome. the cloned fragment, herein designated pov-a6, contained tandemly repeated 334 bp o. viverrini dna and has the potential to be a highly specific and sensitive dna probe. radioactively labelled pov-a6 could detect as little as 25 pg of its own genomic dna and five purified eggs by dot-blot hybridization. the presence of 50 o. viverrini eggs could be readily detected in samples containing faecal m ...19911779978
differential diagnosis of opisthorchiid and heterophyid metacercariae (trematoda) infecting flesh of cyprinid fish from nam ngum dam lake in laos.the examination of flesh of 313 cyprinid fish from the nam ngum water reservoir in vientiane province, laos, revealed the presence of four morphologically similar opisthorchiid and heterophyid metacercariae of medical importance. the following morphological characters, visible under dissecting microscope with low magnification, were typical of trematodes recorded in fish: (1) opisthorchis viverrini, the liver fluke, has oval cysts containing quickly moving c-shaped metacercariae provided with a ...19911822880
opisthorchis viverrini infection in northeast thailand and its relationship to cholangiocarcinoma. 19921327263
a high incidence of liver cancer in khon kaen province, thailand.based on a population-based cancer registry in khon kaen province, thailand, data were collected actively and passively from all hospitals, health centers and the office of the chief medical officer of khon kaen. the data were collected prospectively for the year 1988 and retrospectively for the years 1985-1987. liver cancer, especially cholangiocarcinoma, was the leading cancer in both sexes. the age-standardized incidence rates for the year 1988 were 89.2/10(5) in males and 35.5/10(5) in femal ...19901963706
health status of thai volunteers in a cholera vaccine hundred and seventy-one male adults were screened in recruitment of volunteers for a cholera vaccine trial. a full medical history and a physical examination were performed on each subject. the percentages of subjects vaccinated against cholera and typhoid within twelve months were 4 and 1 per cent respectively, while 88 and 15 per cent respectively had been vaccinated more than a year. biochemical screening revealed abnormal liver function tests in 40.7 per cent, specifically alkaline phosp ...19902280201
rate of re-infection by opisthorchis viverrini in an endemic northeast thai community after chemotherapy. 19883170073
antibodies in serum and bile of hamsters experimentally infected with opisthorchis viverrini. 19883192345
detection of opisthorchis viverrini by monoclonal antibody-based elisa and dna hybridization.monoclonal antibody-based enzyme-linked immunosorbent assay and dna hybridization techniques were developed and evaluated for their potential in the detection of opisthorchis viverrini infection in humans. a mixture of three igg1 monoclonal antibodies (mab) specific for the 89 kda metabolic product of o. viverrini was captured on a microtiter plate by rabbit anti-mouse igg and used in a sandwich elisa for the detection of parasite antigen. the 89 kd component bound to the mab was detected with b ...19912012257
nucleotide sequence of the small subunit ribosomal rna-encoding gene from opisthorchis viverrini.the complete nucleotide (nt) sequence of the small subunit ribosomal rna-encoding gene of opisthorchis viverrini reported in this study is the first nt sequence reported for a trematode. the gene is 1992 nt long and has a g + c content of 50.94%. it is made up of alternated constant and variable regions that are similar to the gene organization of other eukaryotes. it is also of interest to note an unexpectedly high degree of sequence homology between o. viverrini and human genes.19911937023
opisthorchis viverrini: finding and recognition of the fish host by the cercariae.the cercaria of opisthorchis viverrini finds and recognizes its fish host by using at least four steps of behavioral patterns. (1) dispersal and selection of plant-free water microhabitat are achieved by intermittent swimming behavior with positive phototactic orientation. (2) attachment to the host is stimulated by water currents and a hydrophilic component of fish skin surface which has a molecular weight of more than 30,000. this component is sensitive to digestion with hyaluronidase and seem ...19902226703
immunodepression in hamsters experimentally infected with opisthorchis viverrini.hamsters experimentally infected with opisthorchis viverrini had significant depression of the antibody response to sheep red blood cells. the depression was more severe with prolonged infections. lymphoproliferative response to phytohaemagglutinin stimulation was also depressed when compared with uninfected controls. the immunodepression in these animals was abolished by anthelmintic treatment, suggesting that the immunodepressive effect is reversible and is associated with active infection.19873611709
influence of water current on the distribution of opisthorchis viverrini infection in northeastern villages of thailand.the prevalences of opisthorchis viverrini infection in the villages on the banks of rivers and those far from the rivers were studied in loei and nong khai provinces in thailand. most of the people examined in the present study were agriculturalists. the overall prevalence of o. viverrini infection was 41.3%. the prevalence of infection in males and in females in the villages far from the rivers were 52.6% and 51.7%, respectively, while the percent of people in the villages on the banks with inf ...19911948268
characterization of the opisthorchis viverrini genome.the methylations of trematode genomic dna were analyzed using restriction enzymes and southern blot hybridization. restriction enzymes mspi, hpaii, hhai were used to probe cpg methylation while mboi, sau3a, dpni were used for a methylation. the results revealed that opisthorchis viverrini, fasciola gigantica and gigantocotyle siamensis had neither cpg nor a methylations. the presence of highly repeated dna elements was also demonstrated in o. viverrini genomic dna.19912050985
distribution patterns of opisthorchis viverrini within a human community.this paper describes patterns of infection with opisthorchis viverrini within a human community assessed by egg count, parasite-specific antibody levels and worm burden determined by expulsion chemotherapy. all three measurements increased significantly with age, reaching a plateau in young adults. there were no significant sex-associated differences in the prevalence or intensity of infection, antibody levels, or in the frequency of heavy worm burdens. a striking 81.5% of the total opisthorchis ...19911945529
laboratory studies on host-parasite relationship of bithynia snails and the liver fluke, opisthorchis viverrini.the infection rate of bithynia snails to opisthorchis viverrini eggs was studied in relation to exposure intensity, age and species of host. it was found that 50 miracidial eggs per snail yielded the highest percentage of living surviving positive snails. bithynia funiculata and bithynia siamensis siamensis were highly susceptible to o. viverrini, about four to seven times higher than bithynia siamensis goniomphalos. young snails, 1-3 months old, appeared more susceptible than old snails.19911948284
opisthorchis viverrini infection and cholangiocarcinoma. 19852996965
cholangiocarcinoma associated with liver fluke infection: a preventable source of morbidity in asian the far east infection with the liver flukes clonorchis sinensis and opisthorchis viverrini is the most frequently documented cause of cholangiocarcinoma. liver fluke infection in the united states remains a health problem for more than 500,000 southeast asian refugees who have immigrated to this country since 1975. recent surveys have revealed that up to 26% of asian immigrants have an active liver fluke infection. however, the common clinical manifestations of this condition, as well as the ...19863002170
analysis of opisthorchis viverrini antigens by immunoprecipitation and polyacrylamide gel electrophoresis.antigenicity of adult opisthorchis viverrini, metacercariae and eggs was investigated by radio-immunoprecipitation and polyacrylamide gel electrophoresis using sera from patients with opisthorchiasis and from hamsters experimentally infected with o. viverrini metacercariae. 125i-labelled aqueous somatic extract and in vitro metabolic products of adult worms, and the extracts of metacercariae and eggs were immunoprecipitated, electrophoresed and autoradiographed and major antigens were characteri ...19883362572
monoclonal antibodies against opisthorchis viverrini antigens.monoclonal antibodies (moab) were produced against somatic antigens of adult human liver fluke opisthorchis viverrini. earlier studies attached diagnostic potential to an 89-90 kd antigen present in both somatic extracts and in vitro culture supernatants as well as to the abundant 16-17 kd tegumental protein doublet. mice made excellent immune responses to low dose somatic extract adsorbed onto nitrocellulose or to the 80-95 kd region of sds gel western blots. the antigen specificities of hybrid ...19902255563
complement-mediated killing of opisthorchis viverrini via activation of the alternative pathway. 19863744673
diagnosis of opisthorchiasis by enzyme-linked immunosorbent assay using partially purified antigens.opisthorchis viverrini antigens were partially purified from adult worms collected from liver and extrahepatic biliary system of infected hamsters. tegument fraction was obtained by chemical extraction, whereas other fractions were purified by sephadex g-200 gel filtration chromatography. five fractions of o. viverrini antigens were obtained, namely tegument extract, somatic extract, fraction 1 (p1), fraction 2 (p2) and fraction 3 (p3), respectively. the enzyme-linked immunosorbent assay techniq ...19902393450
scanning electron microscopic study of opisthorchis viverrini tegument and its alterations induced by amoscanate. 19863699972
clinical features in severe opisthorchiasis viverrini.clinical features of severe opisthorchiasis were studied in 88 patients. the ratio of males to females was 6.3 : 1; 75% were over 40 years old. the presenting symptoms were obstructive jaundice, 25% associated with secondary infection of biliary system; cholangitis and cholecystitis; intraabdominal mass, which was enlarged liver; 18% had palpable gallbladder; 18% had adenocarcinoma of the bile duct. high bilirubin was found in 46% of cases, high alkaline phosphatase in 80%; elevation of serum tr ...19854095605
report of episthmium caninum (verma, 1935) yamaguti, 1958 (digenea: echinostomatidae) in man.the first finding of episthmium sp. in man is reported. characteristics of the worm are given in detail. the infestation is an accidental one acquired from consuming raw fish, which serves as an intermediate host of opisthorchis viverrini. the pathogenic role of episthmium sp. in man needs further investigations.19854095615
the ultrastructure of helminth. vi. the body wall of opisthorchis viverrini (poirier, 1886). 19714333630
density-dependent fecundity of opisthorchis viverrini in humans, based on faecal recovery of flukes. 19892609378
immunological analysis of opisthorchis and clonorchis antigens.immunoreactive components of opisthorchis viverrini and clonorchis sinensis were analysed by enzyme-linked immunosorbent assay (elisa), radioimmunoprecipitation and immunoblotting. somatic extracts from these two liver flukes as well as from other related parasites, together with the metabolic products, were tested for their reactivities with sera from patients with opisthorchiasis and clonorchiasis. a significant cross-reactivity in the elisa was noted between opisthorchis and clonorchis. immun ...19902201720
generation of high yields of syrian hamster cholangiocellular carcinomas and hepatocellular nodules by combined nitrite and aminopyrine administration and opisthorchis viverrini infection.combined administration of 0.1% nitrite and 0.1% aminopyrine in the drinking water for eight to ten weeks resulted in subsequent development of both hepatocellular nodules and cholangiofibrotic lesions/cholangiocellular carcinomas in syrian golden hamsters. additional prior dosing with opisthorchis viverrini metacercariae (100/animal) induced inflammatory and proliferative changes in the livers of infected hamsters and was associated with a significant increase in yields of hepatocellular and ch ...19882846484
serum glutamyl transferase and other liver function tests in opisthorchis viverrini infection.serum glutamyl transferase (gamma-gt), serum total protein, albumin, aspartate aminotransferase (got), alanine aminotransferase (gpt), alkaline phosphatase and bilirubin were measured in 55 males and 45 females suffering from o. viverrini infection and in apparently healthy non-infected individuals. a decrease in total protein, albumin and bilirubin, as well as an increase in got, gpt and gamma-gt was observed in males with o. viverrini infection, whereas alkaline phosphatase remained unaffected ...19852860715
level of opisthorchis infestation and carcinogen dose-dependence of cholangiocarcinoma induction in syrian golden hamsters.the relationship between different levels of liver fluke, opisthorchis viverrini infestation and dimethylnitrosamine (dmn) dosage in the induction of cholangiocarcinomas was investigated in syrian golden hamsters. two hundred and eighty male, weanling animals were divided into 4 groups: group 1 served as untreated controls; group 2 received o. viverrini metacercariae only at levels of 100, 50, 25 or 12 per animal; group 3 received dmn only at doses of 12.5, 6.25 or 3.125 ppm; group 4 received va ...19872892303
immune responsiveness and parasite-specific antibody levels in human hepatobiliary disease associated with opisthorchis viverrini infection.opisthorchis viverrini infection is associated with human hepatobiliary disease and cholangiocarcinoma, but the role of the immune response in the pathogenesis of infection is unclear. here ultrasonography was used to examine the biliary tracts of residents from an endemic community. delayed-type hypersensitivity responses to unrelated antigens, and fluke-specific igg and iga levels in serum of this group were also examined. relationships between immunological parameters, intensity of infection ...19912025950
species determination of eggs of opisthorchiid and heterophyid flukes using scanning electron microscopy.eggs of opisthorchiid flukes have very characteristic muskmelon-like surface structure of their shells and can be differentiated using this mark from eggs of heterophyid flukes. surface structure and morphological details in operculum and abopercular end can be observed using scanning electron microscopy. eggs recorded very often in stool of laotians belong mostly to opisthorchis viverrini and sporadically to metagonimus yokogawai.19902337251
peritoneoscopic findings in 203 patients with opisthorchis viverrini infection.a study was conducted to determine the value of peritoneoscopy in the diagnosis of opisthorchiasis. peritoneoscopic findings in 203 proven cases of opisthorchis viverrini infection are presented. the authors found that cholangiocarcinoma is frequently encountered in patients presenting with prolonged jaundice and hepatomegaly as well as with the peritoneoscopic findings of dilated superficial intrahepatic bile ducts, a bile-stained liver surface and a markedly enlarged gallbladder.19872951293
studies on the chemotherapy of human opisthorchiasis: effective dose of praziquantel in heavy infection.ninety-six patients who had heavy opisthorchis viverrini infection were studied. egg count per gram of faeces ranged from 10,800 to 139,000 (mean 26,044.3). praziquantel 50 mg per kg body weight was given after a morning meal. 68 patients completed the follow up period of 60 days. the cure rate was 97.0%. the side-effects occurred in 61 patients (89.7%). the common side effects were diarrhoea, dizziness, sleepiness, epigastric pain, headache, nausea and anorexia. these side-effects were mild and ...19853906918
enhancement of dhpn induced hepatocellular, cholangiocellular and pancreatic carcinogenesis by opisthorchis viverrini infestation in syrian golden hamsters.infection with 100 opisthorchis viverrini (op) metacercariae prior to two injections of dihydroxy-di-n-propyl nitrosamine (dhpn) (1000 mg/kg body weight) brought about significant enhancement of resultant preneoplastic lesion development in syrian hamster liver and pancreas tissue. thus combined treatment with carcinogen and parasite was associated with pancreatic atypical (dysplastic) foci, hepatocellular nodules, cholangiofibrosis and cholangiocarcinomas. no such lesions were observed in carci ...19882836105
opisthorchis viverrini infection and cholangiocarcinoma. a prospective, case-controlled study.during a prospective, 24-mo case-controlled study, 551 patients from northeastern thailand were independently evaluated for opisthorchis viverrini infection, hepatobiliary tract disease, and hepatic carcinoma to determine whether there was any association between hepatic carcinoma and o. viverrini infection. stool examination by the formalin-ether concentration method revealed o. viverrini ova in 389 (70.6%) patients. of the 551 patients, 72 (13.1%) had both clinical and laboratory evidence of h ...19852989071
clinical manifestations of opisthorchis viverrini infections in thailand. 19665959105
field studies on the transmission of the human liver fluke, opisthorchis viverrini, in northeast thailand: population changes of the snail intermediate host. 19863781736
human pathology of opisthorchis viverrini infection: a comparison of adults and children.the pathology of human opisthorchiasis in 22 adults (20 to 68 years) and 7 children (7 to 15 years) at autopsy is described. the changes of the liver in adults and children are similar and are summarized as follows: enlargement of the liver was a common finding. pericholangitis was observed in most cases. the pathology was confined to the large and medium-sized bile ducts where the flukes inhabited. the small interlobular bile ducts had minimal or unremarkable changes. dilatation of the bile duc ...19892772709
a high frequency of hepatobiliary disease and suspected cholangiocarcinoma associated with heavy opisthorchis viverrini infection in a small community in north-east thailand.a group of 87 adults from a small village in north-east thailand was chosen to undergo ultrasound investigation based on their intensity of infection with the liver fluke, opisthorchis viverrini, or clinical status (history of jaundice, current hepatomegaly). from this group, 8 cases of suspected early cholangiocarcinoma were found, and the diagnostic features of 6 of the 8 were confirmed by computerized tomography scan and endoscopic retrograde cholangiopancreatography. in addition, several cas ...19902177578
detection of antibodies against opisthorchis viverrini in patients before and after treatment with praziquantel.levels of antibody in sera of 78 patients with opisthorchiasis, 30 patients with other liver diseases, 10 patients with schistosomiasis and 30 healthy individuals were compared using three serodiagnostic tests, namely indirect haemagglutination (iha), enzyme-linked immunosorbent assay (elisa) and lectin immuno test (lit). the geometric mean reciprocal titer in sera of opisthorchiasis patients was significantly higher than patients with other diseases, patients with schistosomiasis and healthy in ...19883136551
a characteristic immunoblotting pattern for opisthorchiasis sera with metacercarial antigens.the protein compositions of homogenized metacercaria and adult opisthorchis viverrini were characterized by sodium dodecyl sulphate polyacrylamide gel electrophoresis (sds-page). the two different stages of o. viverrini parasite contained several protein components with very similar mobilities on sds-page gel. the reaction in immunoblots of sera from patients with opisthorchiasis demonstrated antibodies against heterogeneous protein components of metacercariae and adult o. viverrini parasites. o ...19883233789
liver procollagen prolyl hydroxylase in opisthorchis viverrini infected hamsters after praziquantel administration.infection of hamsters by the human liver fluke opisthorchis viverrini elevated liver procollagen prolyl hydroxylase activity, reflecting increased collagen biosynthesis. the increase was proportional to the intensity of infection. however, the infected liver procollagen prolyl hydroxylase activity decreased after administration of praziquantel 300 mg kg-1 body weight, and approached normal levels two weeks after treatment. in the infected hamsters, praziquantel, at a curative dose, caused a tran ...19836318107
opisthorchis viverrini eggs and adult flukes as nidus and composition of gallstones.three cases of opisthorchiasis with calculous cholecystitis was presented. the diagnosis of gallstones was made before praziquantel therapy in 2 cases, and 4 years after treatment in one case. the patients underwent cholecystectomy. numerous o. viverrini eggs and one dead fluke were found in the bile in one case. a single stone was recovered from each gallbladder. all stones contained o. viverrini eggs. fragments of flukes were also present in two cases. the stones consisted of a mixture of bili ...19883238475
characterization of humoral immune response in the serum and bile of patients with opisthorchiasis and its application in immunodiagnosis.the humoral immune response in patients with opisthorchiasis was investigated using an enzyme-linked immunosorbent assay. igg antibody reactive with opisthorchis viverrini antigens was present in the serum of all patients. the infection also stimulated specific iga and ige antibody responses in most patients and, in practically all patients, there was a marked increase of total ige. there was a moderate but significant correlation between serum igg antibody level and severity of infection as jud ...19883354768
immunization of hamsters against opisthorchis viverrini infection.attempts were made to induce acquired immunity against opisthorchis viverrini infection in hamsters by immunizing them with aqueous somatic extract and metabolic products of adult worms, crude adult worm homogenates and metacercarial somatic extracts via either the intraperitoneal or combined intraperitoneal and oral routes. these procedures failed to stimulate significant protective response in animals that had never been exposed to o. viverrini. however, the protective response reached a signi ...19863576286
analysis of opisthorchis viverrini antigens: physicochemical characterization and antigen localization.antigens of opisthorchis viverrini were identified and characterized by enzyme-linked immunosorbent assay, polyacrylamide gel electrophoresis following radioimmuno-precipitation, and indirect immunofluorescence. the immunoreactive protein with a relative molecular weight (mr) of 89 kd was the predominating component of the parasite metabolic products. an immunofluorescence study showed it to be associated with parasite eggs, linings of the reproductive system and secretions therein. protein of t ...19873329412
hemobilia and liver flukes in a patient from thailand.a patient from southeast asia presented with abdominal pain, fever, jaundice, and upper gastrointestinal bleeding of unknown origin. opisthorchis viverrini eggs were found in the stool and multiple hepatic filling defects were noted on liver scan and sonogram. endoscopic retrograde cholangiopancreatography revealed cholelithiasis and crescent-like filling defects in the biliary system. at surgery, the gallbladder was filled with clotted blood and pigmented stones. during t-tube drainage of the c ...19853996848
opisthorchis viverrini: pathogenesis of infection in immunodeprived hamsters.opisthorchis viverrini infections were established in immunologically intact and t cell deprived hamsters. t cell deprivation appeared to have no effect on worm establishment or egg production. histopathologically, intact and deprived animals showed similar degrees of bile duct hyperplasia and periductular fibrosis, though there was a marked reduction in the intensity of the periportal inflammation in the majority of t cell deprived animals. serum transaminase levels were significantly raised in ...19863490651
treatment of opisthorchiasis viverrini in hamsters with albendazole.efficacy of many drugs against opisthorchis viverrini in man were shown by the percentages of egg reduction and the absence of egg in faeces. in some cases, however, the eggs reappeared after a period of time. the pathological changes of the bile duct could cause partial or even complete obstruction of the bile passages, thus resulting in the occurrence of natural egg reduction. albendazole, a broad spectrum anthelmintic was used to treat opisthorchiasis viverrini in hamsters. at dosage of 100 m ...19846523174
measurement of incidence of the human liver fluke, opisthorchis viverrini, in northeast thailand.a survey of a community in northeast thailand where opisthorchis viverrini is endemic permitted comparison of two methods of measuring incidence: direct determination of the rate at which an uninfected group became infected between two surveys a year apart, and estimation of incidence from age-specific prevalence data using a logarithmic regression method. both methods revealed that incidence increased with age in young children, and estimation from age-prevalence data showed that the increase w ...19873617199
opisthorchis viverrini infection in rural and urban communities in northeast thailand.the prevalence and intensity of liver-fluke (opisthorchis viverrini) infection were investigated among 559 patients who were born in, and had lived all their lives in, either the rural or urban northeastern thailand. 344 (79.4%) of 433 rural dwellers were infected compared with only 69 (54.8%) of 126 urban dwellers (p less than 0.005). the intensity of infection, and the reported level of consumption of koi-pla, a favourite dish of local inhabitants prepared from uncooked freshwater fish which o ...19873686637
high urinary excretion of nitrate and n-nitrosoproline in opisthorchiasis subjects.about 50% of the population in some provinces of north-east thailand are infested with liver fluke (opisthorchis viverrini), and many develop cholangiocarcinoma subsequently. this study was designed to demonstrate possible endogenous formation of n-nitrosoproline (npro) in this population. diet samples, saliva and urine were taken from subjects with and without liver fluke and analysed for nitrate and nitrite; urine was also analysed for npro. nitrate and nitrite levels in saliva were higher in ...19873679440
types of collagen in opisthorchis viverrini infected hamster liver.levels and types of collagen from normal and opisthorchis viverrini infected hamster livers were compared. normal liver contained approximately twice as much type i collagen than type iii collagen. upon infection by o. viverrini, both type i and type iii collagen were elevated, but the increase in type iii was proportionately larger than type i collagen. of the 3-fold increase in total collagen content of infected livers, type i and type iii collagen increased 2- and 4-fold, respectively. as a r ...19863960058
potentiation by the human liver fluke, opisthorchis viverrini, of the carcinogenic action of n-nitrosodimethylamine upon the biliary epithelium of the hamster. 19826295426
increased liver prolyl hydroxylase activity in hamsters infected with the human liver fluke opisthorchis viverrini.a parallel increase in liver collagen content and prolyl hydroxylase activity was observed in hamsters infected with the human liver fluke opisthorchis viverrini. they were elevated at 2 weeks after infection, gradually increased to approximately 2-fold at 7-11 weeks of infection, and then declined as with duration of infection time increasing from 11 to 22 weeks.19836309553
stimulation of ca2+ uptake in the human liver fluke opisthorchis viverrini by praziquantel.45ca2+ uptake by the human liver fluke opisthorchis viverrini is enhanced by praziquantel. the drug-induced 45ca2+ uptake was dependent on the presence of ca2+ and was attenuated in the presence of 10 mm mg2+. la3+ and vanadate at concentration of 1 mm partially reduced the amount of 45ca2+ uptake into the liver fluke in response to praziquantel treatment. the stimulating effect of praziquantel was eliminated in the presence of 10 microm verapamil. these findings suggest that praziquantel increa ...19836304438
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