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1.
This study reports the early biochemical changes in plasma, comparative host-immune responses and parasite recovery data in Merino sheep during the first 10 weeks of infection with Fasciola gigantica and Fasciola hepatica. One group of sheep were uninfected, four groups of sheep received incremental challenge doses of F. gigantica metacercariae (50, 125, 225 and 400, respectively) and the sixth group was challenged with 250 F. hepatica metacercariae. At 10 weeks post infection (wpi), sheep challenged with F. hepatica showed the greatest fluke recovery (mean 119, range 84-166); a significantly higher biomass of parasites recovered (2.5-fold greater than the highest dose of F. gigantica); and a greater mean % parasite recovery (39.3%, range 27-55%) than any group challenged with F. gigantica. Within the groups dosed with F. gigantica a strong dose-dependent response was observed in both fluke recovery and fluke biomass with increasing dose of metacercariae. The mean % parasite recovery of F. gigantica infected groups 1-5 were 26, 23, 26 and 25%, respectively, suggesting a uniform viability of parasite establishment independent of infection dose. At 6 wpi, elevated levels of plasma GLDH were observed in the F. gigantica infected groups compared to the uninfected sheep (p<0.005) whereas the F. hepatica challenged group had four-fold higher levels of GLDH compared to the F. gigantica infected group (p<0.001). Elevated levels of GGT as an indicator of epithelial damage in the bile duct was only seen in the group challenged with F. hepatica at 10 wpi when it rose from below 100 IU/l to approximately 250 IU/l (p<0.0001) whereas no detectable increase in GGT was observed in any of the groups challenged with F. gigantica. The white blood cell response to F. hepatica infection was biphasic with the initial peak at 4 wpi and a second peak at 9 wpi, corresponding to the period of migration of juvenile fluke in the liver and the time when adult flukes are migrating into the bile duct, respectively. This biphasic response was also evident in the changes in the eosinophil counts and serum haemoglobin levels. There was a trend toward higher parasite-specific IgG2 titres in sheep infected with lower worm burdens, suggesting that higher F. gigantica or F. hepatica burdens suppress IgG2 responses. The findings of this study suggest that, in early infection in a permissive host, F. hepatica appears to be more pathogenic than F. gigantica because of its rapid increase in size and the speed of its progression through the migratory phases of its life cycle.  相似文献   

2.
Haemoglobin, packed-cell volume and serum sorbitol dehydrogenase activity were studied in 8 groups of 3 Corriedale weaner wethers artificially infected with a range of fluke burdens. Data from haemoglobin and packed-cell volume measurements were analysed using regression procedures. All parasitised groups exhibited a decrease in haemoglobin and packed-cell volume compared with the control group. The rate of this decrease was approximately linear, and dependent on the size of the fluke burden. Prediction equations for the rates of decrease of haemoglobin and packed-cell volume in fluke-infected sheep are presented. Death occurred when haemoglobin fell below 5 g 100 ml-1, and packed-cell volume to 15%. Anaemia became profound in sheep infected with more than 346 flukes and these sheep died 56-63 days after infection. Serum sorbitol dehydrogenase activity exhibited several peaks, before and after Week 12 post-infection, when flukes should have been present in the bile ducts. Reason for the activity later than Week 12 was not clear, although stress or immune responses may contribute. Haemoglobin and packed-cell volume may be useful in predicting the size of fluke burdens when the duration of the infection is known, and may indicate that time of death of infected sheep. Sorbitol dehydrogenase is an unreliable indicator of the size or the duration of fluke burdens.  相似文献   

3.
The efficacies of putative fasciolicides and vaccines against Fasciola hepatica are frequently monitored in clinical and field trials by determination of fluke egg output in host faeces and by worm counts in the host liver at autopsy. Less often used are parameters based on fluke size and histology, yet these can provide important indications of specific effects on the development of particular germ-line or somatic tissues, especially in relation to the timing and profligacy of egg production. In this study, F. hepatica metacercariae of two distinct isolates, the triclabendazole (TCBZ)-sensitive Cullompton isolate and the TCBZ-resistant Oberon isolate, were administered to rats as single-isolate or mixed-isolate infections. At autopsy 16 weeks later individual adult flukes were counted, measured and the reproductive organs were examined histologically. The degree of development of the testis tubules in each fluke was represented by a numerical score, based on the proportion of the histological section profiles occupied by testis tissue. The level of anti-F. hepatica antibody in the serum of each rat was determined by ELISA. It was found that Cullompton flukes were significantly larger than Oberon flukes, and that significantly more Cullompton metacercariae developed to adults than Oberon metacercariae. The Cullompton flukes showed histological evidence of aspermy and spermatogenic arrest, which was reflected in quantitatively reduced testicular development, as compared with the Oberon isolate. In Cullompton flukes, parthenogenetic egg development is implied. The size of Cullompton and Oberon flukes was significantly related to the number of adult flukes recovered, to the number of metacercariae administered, and to the percentage success of infection. The testis development score in both isolates was significantly related to the number of adult flukes recovered but not to the number of metacercariae administered, or to the percentage success of infection. Fluke size was positively related to testis score for both isolates, and a significant negative relationship was found between percentage success of infection and metacercarial dose. The results are interpreted in terms of differing interactions between various numbers of young flukes and host immunity during invasion of and migration in the hepatic parenchyma, and of fluke intra-specific (possibly pheromonal) stimulatory effects in the final stages of development, within the host bile ducts. No significant relationships were found between host antibody levels and fluke size or testis score. False positive serological reactions were found in some rats that had been infected, but found to harbour no flukes at autopsy. Clearly the act of eliminating the flukes involved generation of an immune response.  相似文献   

4.
Changes in the common bile duct that contained adult Fasciola hepatica of sheep were evaluated by light (LM) and scanning electron microscopy (SEM). Nine ewes were inoculated with F hepatica metacercariae and necropsied 18 weeks after inoculation. The proximal portion of the common bile duct (CBD) that contained adult flukes was recovered and examined by LM and SEM. The CBD from 2 noninoculated ewes were used for control. On gross examination, CBD were markedly large because of the adult flukes, which were free in the lumen of the ducts. Extensive hemorrhage was not found either in intrahepatic or in extrahepatic bile ducts of any sheep. Histologic examination revealed changes, such as villous hyperplasia and hypertrophy of the epithelium; cell infiltration, predominantly with eosinophils or macrophages; and arterial intimal proliferation. By SEM, the epithelial surface of the CBD appeared intact. Villous hyperplasia and hypertrophy of the epithelium observed by LM was clearly seen by SEM. Epithelial damage, seen as small areas of denuded surface by LM and SEM, was confined to a few areas of the mucosa. Lack of extensive hemorrhage and confined epithelial damage were evaluated relative to the mode of feeding of adult flukes.  相似文献   

5.
Vaccination of sheep with either 100 or 1000 γ-irradiated (2.5 krad) metacercariae of Fasciola hepatica, on two occasions six weeks apart, did not generate significant protection against intraruminal challenge with F. hepatica six weeks after the second vaccinating dose as measured by recovery of flukes from liver and bile ducts, twenty weeks after challenge. There was, however, a significant increase in the proportion of flukes retarded in the parenchyma of both vaccinated groups. The percentage of retarded flukes was positively correlated with the degree of liver damage and increased weight of the hepatic lymph nodes. It was not possible to determine if the retarded flukes were derived from the vaccine or challenge infections or both.Challenge infection of both vaccinated and unvaccinated sheep significantly increased the numbers of eosinophils and globule leucocytes in the parenchymal bile duct and the numbers of mast cells and globule leucocytes in the abdominal bile duct. In addition the numbers of eosinophils and globule leucocytes in the parenchymal bile duct were significantly correlated with the percentage of retarded flukes in both vaccinated groups. In the abdominal bile duct, only the numbers of eosinophils in the low level vaccination group were significantly correlated with fluke retardation.Vaccination did not protect against the pathogenic effects of challenge infection as measured by reduced packed cell volumes and weight gain.  相似文献   

6.
Innate resistance of Javanese thin-tailed sheep to Fasciola gigantica was investigated in animals infected with single doses of 150 or 500 metacercariae and killed 4, 8, 12 or 16 weeks after infection. Infected and non-infected sheep had similar values for packed cell volume, mean corpuscular volume, mean corpuscular haemoglobin concentration, serum glutamate dehydrogenase, serum gamma glutamyl transferase and serum aspartate transferase throughout the trial, except for one animal infected with 500 metacercariae from which the highest recovery of flukes (55) was made. This animal developed pathologically altered values from 12 weeks post infection, coincident with the period of greatest hepatic haemorrhage and destruction of hepatic tissue by migrating flukes and their entry into bile ducts. However, values were altered much less than those reported in other sheep given as few as 200 metacercaria of F. gigantica. Both susceptibility to infection with F. gigantica, as indicated by percentage take of metacercariae and the severity of pathological changes were low in this study in comparison with reports involving other breeds of sheep infected with this parasite. These findings support the conclusion that Javanese thin-tailed sheep have a high innate resistance to F. gigantica.  相似文献   

7.
A characterization of the humoral immune response of alpacas to Fasciola hepatica Fas1 and Fas2 antigens, two abundant cysteine proteinases in the excretory/secretory (E/S) products, was performed over the course of 6 months of experimental infection. Six adult alpacas aged 1-2 years old received a single dose of 200 F. hepatica metacercariae; two non-infected alpacas were kept as control group. All infected animals shed eggs 8 weeks post-infection (PI) and the number of flukes recovered at necropsy averaged 41+/-4. The livers of infected animals showed regions with chronic inflammation, granuloma containing parasite eggs, necrosis and cirrhosis. Peripheral eosinophilia in infected animals was greatly enhanced 6 weeks post-infection and later. A single peak of serum glutamic piruvic transaminase (SGPT) was observed 4 weeks PI and serum glutamic oxalacetic transaminase (SGOT) elevated 3 weeks PI and later. Circulating IgG Abs against Fas1 and Fas2 were measured by enzyme-linked immunosorbent assay (ELISA). Fas2-ELISA detected the infection 10 days PI reaching to highest titer on 7-8 weeks PI and kept elevated, until the end of infection. Fas1-ELISA detected the infection 2 weeks PI and followed the same pattern as Fas2-ELISA. Anti Fas2 IgG Abs were in higher titers and showed stronger avidity than anti Fas1 IgG Abs. In addition, rabbit IgG antibodies raised against cysteine proteinase Fas2 showed infiltration of this parasite antigen associated to the degradation of bile ducts and liver parenchyma of infected alpacas. In the present study we have established a F. hepatica experimental infection of alpacas, Fas2 appears to have a role in the pathogenesis of the liver damage in alpacas caused by the liver fluke. Infected alpacas elicited a strong humoral immune response against fluke cysteine proteinases Fas1 and Fas2, which might be considered as candidates for immunodiagnosis and vaccine development against fasciolosis in alpacas.  相似文献   

8.
Three white-tailed deer (Odocoileus virginianus) were inoculated with 1000 metacercariae of Fasciola hepatica and examined on days 7, 14, and 28 postinoculation to determine the early response of a resistant host to this infection. It was concluded that only small numbers of the metacercariae penetrated the intestinal wall into the peritoneal cavity. Flukes that migrated to the liver penetrated through Glisson's capsule, primarily on the parietal surface. Marked fibroplasia and cellular infiltration of the capsule were induced and flukes were killed and destroyed in granulomas immediately beneath the capsule. Migration in hepatic parenchyma was minimal and immature flukes or migratory tracks were not found. There were infiltrations of eosinophils and mononuclear cells, bile duct hyperplasia and fibroplasia in portal areas. A few flukes penetrated through the diaphragm within 14 days postinoculation and on day 28 granulomas were observed on the dorsal surface of the lung where F. hepatica had penetrated this organ. The early reaction of Glisson's capsule to F. hepatica infection in white-tailed deer has not been described in cattle, sheep or swine infected with this fluke.  相似文献   

9.
Tracer sheep were used to determine the temporal distribution of acquisition of F. hepatica on both irrigated and non-irrigated areas an area of northern Victoria where this parasite is endemic, for the period November 1974 to November 1976.
Throughout the study, very few flukes were acquired on the non-irrigated experimental area, and of this small number most were acquired by sheep in late spring and early summer. Flukes were acquired throughout both experimental years on the irrigated experimental area. The intensity of infection was lowest in late winter and early spring, but acquisition was substantial when measured over a year, being 483.5 in the first year and 1234.6 flukes per sheep in the second year.
The productivity of these animals was lower than that of equivalent animals kept on an area free of fluke, but quantitative interpretation of this information is confounded by the effect of the presence of an area with atypically high moisture levels (the snail habitat) on pasture production in the area grazed by the infected animals. The differences recorded are therefore likely to be underestimates of the true difference.
A suitable treatment regimen for control of liver fluke in sheep in northern Victoria is outlined.  相似文献   

10.
Sixteen calves approximately 6 months old were each infected with 500 metacercariae of Fasciola hepatica. Thirty-two days later they were weighed and divided into two groups, and on day 35 all calves in one of the groups were injected subcutaneously with an ivermectin/closantel combination. Both groups were sacrificed between days 70 and 72 to enable counting and examination of the flukes recovered from the bile ducts. Eggs released by the flukes were collected for incubation, hatching and estimation of egg viability. Flukes were counted, flat-fixed in 70% ethanol, stained with catechol and carmine and measured. The reproductive organs, namely testis, vitelline glands, ovary and uterus, were examined and scored on a 0-3 scale according to their state of development. This was visually assessed on the basis of size, distribution and staining density of their constituent tissues and the abundance of eggs in the uterus. A representative sample of flukes from each animal was fixed in formalin for histological sectioning to enable more detailed examination of the reproductive structures. Treatment of the immature flukes reduced the population in cattle by 42.6% as compared with the controls and as a result of the stunting effect due to the presence of closantel during early development the size of treated flukes was reduced by 43.9%. A bimodal pattern of size and reproductive score was also observed in flukes from treated cattle, suggesting that the stunting effect on individual flukes differed depending on whether or not they had gained access to the bile ducts or were still migrating in the hepatic parenchymal tissue at the time of drug exposure with the effect being greater once the fluke had gained access to the bile ducts. The mean reproductive score for untreated flukes was 8.76 and for treated flukes 5.64, a 35.6% reduction. This difference was highly significant (p<0.001). Egg shedding from treated flukes was significantly less than that from controls (p<0.05), but there were no differences in hatchability, suggesting that whilst drug treatment reduced the energy supply available for gametogenesis/oogenesis, it did not induce functional defects in the gonads or accessory reproductive organs. Histological examination confirmed that there was a reduction in development of testes, ovaries and vitellaria in treated flukes, with a consequent reduction in egg production. In the treated flukes, early spermatogonia and oogonia were the predominant cell types in the testes and ovary, whilst undifferentiated stem cells were abundant in the vitelline follicles. In untreated flukes, cells representing more advanced stages in gametogenesis and vitellogenesis predominated in the respective organs. It is likely that this inhibition of gametogenesis and vitellogenesis was caused by the effects of closantel treatment on intermediary metabolism in the flukes. Clearly these effects were evident even at a relatively early stage of fluke growth, and because of the impact on egg output may have epidemiological importance in addition to the reduction in fluke numbers.  相似文献   

11.
Sheep were infected with 100 metacercariae of Fasciola hepatica and reinfected 16 weeks later with a further 100 metacercariae. Serum samples were taken weekly for 36 weeks after primary infection. Serum was assayed for the presence of the enzymes glutamate dehydrogenase (GLDH) and gamma-glutamyl transferase (gamma-GT), as indicators of liver and bile duct damage respectively, and for levels of precipitating antibody. Antibody and GLDH levels rose following the primary infection but fell after patency had been reached . A peak in gamma-GT activity was associated with the onset of patency. After the challenge infection levels of both enzymes rose substantially and there were persistent fluctuations in activity. Antibody levels did not rise markedly following challenge but fluctuated at low levels until autopsy, 20 weeks after challenge. There was no resistance to challenge judged by worm recoveries at autopsy. It is suggested that the presence of adult flukes in the bile ducts suppresses the antibody response to challenge infection. Tissue damage, which is shown by fluctuations in GLDH and gamma-GT levels after adult flukes have become established in the bile ducts, is considered to be due to the feeding activity of adult flukes and the deposition of immune complexes in the liver parenchyma.  相似文献   

12.
To determine the extent to which wild deer are contributing in the transmission of Fasciola hepatica (liver fluke) livers from deer shot by hunters, farmers undertaking population control on their farms and vertebrate pest controllers were collected and frozen. The livers were later thawed, sliced and examined for the presence of adult flukes or evidence of past infection. Livers from 19 deer were examined (18 fallow [Dama dama] and one sambar [Rusa unicolor]). Seventeen of the fallow deer were animals collected on farms near Jindabyne, New South Wales. The remaining fallow deer was collected in the Australian Capital Territory and one sambar deer was collected in north-eastern Victoria. Nine of the 17 deer (53%) from the Jindabyne area were either infected with Fasciola hepatica (liver fluke) or had thickened bile ducts indicating past infection. Infection levels in the infected animals varied widely from 3 liver fluke to over 50 per liver. No sign of infection was present in the deer from the Australian Capital Territory or Victoria. Fallow deer are wide-spread in the Jindabyne area and their population is increasing. It is likely their contribution to the maintenance and distribution of F. hepatica to livestock in the Jindabyne area, and in other livestock rearing areas of south-eastern Australia, is important and increasing.  相似文献   

13.
396 red foxes originating from the city of Berlin were examined for opisthorchiid liver flukes and clinical sarcoptic mange between January 1997 and March 1998. Out of 232 (= 58.6%) foxes positive for opisthorchiid flukes 221 animals harboured Metorchis bilis and 70 were infected with Opisthorchis felineus. Pseudamphistomum truncatum was found only in 8 foxes. M. bilis occurred as mono-infection in 154 animals. M. bilis in combination with O. felineus was found in 61 cases. Pure Opisthorchis infection as well as other fluke combinations were found in a small number of animals only. 85 (= 21.5%) foxes showed clinical sarcoptic mange. Liver fluke positive foxes showed a higher mange prevalence than uninfected animals. However, significant associations between flukes and manage were only found when comparing uninfected foxes with those having the highest worm burden. The association of liver flukes and mange could be established for adult female foxes by a significant Odds Ratio of 4.3.  相似文献   

14.
Platynosomum fastosum is a small fluke found in the biliary ducts and gallbladder of cats. Its lifecycle includes the snail Sublima octona as intermediate host, and lizards, toads and geckos as paratenic hosts. Affected cats are usually adult and acquire the parasite by feeding on infected lizards. This parasite occurs across the world but is more frequent in tropical areas. The clinical signs range from none to obstruction of the biliary tract, with hepatic failure and death, reinforcing the necessity of including the liver fluke Platynosomum fastosum in the differential diagnosis of hepatic diseases in cats. This report describes an unusual case of a cat with a polycystic hepatic disease and a severe infestation by Platynosomum fastosum and presents a review of the literature.  相似文献   

15.
The effect of infection with the liver fluke Fasciola hepatica on serum, bile and faecal immunoglobulin and antibody levels was studied in Scottish Blackface sheep. In the serum the immunoglobulins showing the most marked increase were IgG1 and IgG2 and their maximal values were reached at 16 weeks after infection. In the bile IgG2 rose to peak values at two weeks and IgG1, IgA and IgM were maximal at four weeks after infection. The levels of faecal IgG and IgA were low after primary infection but after reinfection a rapid increase in IgA concentration was observed within one to two weeks. Haemagglutinating antibody levels against egg antigens, juvenile and adult excretory-secretory antigens and adult fluke somatic antigens were evaluated. In the sera high titres were observed starting from two to four weeks after infection and persisting until 14 to 16 weeks. Bile haemagglutinating antibodies against excretory-secretory antigens showed the highest level at two and four weeks after infection while antibodies against adult somatic antigens reached maximal titres between four and eight weeks. Faecal antibody levels after primary infection were low but increased rapidly within two weeks after reinfection, coinciding with the elevation in faecal IgA concentration. However, there was no reduction in the number of flukes established in reinfected animals.  相似文献   

16.
The objective of this study was to evaluate the efficacy of a pour-on solution containing moxidectin plus triclabendazole (MOX plus TCBZ) against immature and adult stages of the liver fluke in cattle and compare the efficacy with other commercially available preparations. To this end, 104 male Holstein-Friesian calves aged between 3 and 4 months, were randomly allocated to 13 groups of eight animals each, and infected with approximately 500 Fasciola hepatica metacercariae. One group remained untreated, four groups were treated with MOX plus TCBZ at a dose rate of 0.1mL/kg, four other groups were treated with ivermectin (IVM) plus clorsulon injectable at a dose rate of 0.02mL/kg, and the remaining four groups were treated with IVM plus closantel pour-on at a dose rate of 0.1mL/kg. Each treatment was applied to one of the groups at 4 weeks, 6 weeks, 8 weeks and 12 weeks after the experimental infection. At necropsy (99-102 days after infection), all untreated animals were infected with a minimum of 30 flukes. The MOX plus TCBZ treated animals had significantly (P<0.0001) lower fluke counts compared to the untreated control animals at all time points after treatment. Efficacy against 8-week old and adult flukes was >99.5%. For 6-week old immature fluke, the efficacy was 98.0% and for 4-week old immature fluke the efficacy was 90.9%. The IVM plus closantel pour-on treated animals had significantly lower fluke counts compared to the untreated control animals for adult and 8-week old flukes (P<0.0001), and for 6-week old flukes (P=0.002). The efficacy was 26.8%, 68.2%, 90.6% and 99.3% against 4-week, 6-week and 8-week old immature flukes, and adult flukes respectively. The IVM plus clorsulon treated animals had significantly lower fluke counts compared to the untreated control animals for adult (P<0.0001) and 8-week old (P<0.05) flukes. The efficacy was 29.7%, 43.4%, 53.2% and 99.2% against 4-week, 6-week and 8-week old immature flukes, and adult flukes respectively. For treatments at 4, 6 and 8 weeks after infection, the fluke counts were significantly (P<0.0001) lower for the MOX plus TCBZ treatment than for IVM plus closantel or IVM plus clorsulon. The results confirm the high efficacy (>90%) of the MOX plus TCBZ pour-on combination against 4-week old to adult liver fluke in cattle. The IVM plus closantel pour-on combination was effective (>90%) against 8-week old and adult flukes, but had low efficacy against 4- and 6-week old fluke. The IVM plus clorsulon injectable combination was effective (>90%) against adult fluke only.  相似文献   

17.
Comparisons were made between the flukes from Chonnam, Korea and Oregon, USA by isoelectric focusing (IEF) of whole-body protein. Adult Fasciola hepatica were recovered from bile ducts of Korean native cattle. Whole-body protein of the flukes was subjected to IEF, and the banding patterns of the fluke protein were compared with those of North American F. hepatica recovered from experimentally infected calves. The overall banding pattern of F. hepatica from Korea was essentially identical to that of F. hepatica from the United States. These results provide further support for the usefulness of this technique in differentiating Fasciola species in other geographical areas.  相似文献   

18.
The highest prevalences and intensities of human fasciolosis by Fasciola hepatica are found in the northern Bolivian Altiplano, where sheep and cattle are the main reservoir host species and pigs and donkeys the secondary ones. Morphometric comparisons of many linear measurements, areas and ratios of F. hepatica adults (from sheep, cattle and pigs) and eggs (from sheep, cattle, pigs and donkeys) in natural liver fluke populations of the Bolivian Altiplano, as well as of F. hepatica adults and eggs experimentally obtained in Wistar rats infected with Altiplanic sheep, cattle and pig isolates, were made using computer image analysis and an allometric model. Although morphometric values of adult flukes from natural populations of sheep, cattle, and pigs showed great overlap, there were clear differences in allometric growth. The allometries analyzed were: body area (BA) versus body length (BL), BA versus body width (BW), BA versus perimeter (Pe), BA versus distance between posterior end of body and ventral sucker (P-VS), BL versus BW, BL versus Pe, and BL versus P-VS. These allometries show a good fit in the seven pairs of variables in all the populations examined. Comparative statistical analysis of the allometries shows that fluke adult populations from sheep, cattle and pigs significantly differ in BL versus BW and BL versus P-VS functions. Statistical analysis of F. hepatica egg size shows characteristic morphometric traits in each definitive host species. In experimentally infected rats, fluke adult allometry and egg morphometry do not vary depending on the Altiplanic definitive host species isolate. Our study reveals that the definitive host species decisively influences the size of F. hepatica adults and eggs, and these influences do not persist in a rodent definitive host model.  相似文献   

19.
The pattern of in vivo uptake of albendazole (ABZ) and its major metabolite, ABZ-sulphoxide (ABZSO), by Haemonchus contortus and Fasciola hepatica recovered from ABZ-treated sheep, was investigated. Concentration profiles of both compounds were simultaneously measured in target tissues/fluids from the same infected sheep. In addition, the proportion of the (+) and (-) ABZSO enantiomers was determined in plasma, bile and F. hepatica recovered from treated sheep. Sheep naturally infected with H. contortus were intraruminally (i.r.) treated with ABZ (micronized suspension, 7. 5mg/kg) and the plasma concentrations of ABZSO and ABZ-sulphone (ABZSO(2)) determined in addition to the concentration of ABZ and ABZSO in H. contortus, abomasal mucosa and fluid content samples. In addition, F. hepatica artificially infected sheep were treated i.r. with the same ABZ suspension (7.5mg/kg), and samples of blood, bile, liver tissue and adult flukes were collected and analysed by HPLC to determine the concentrations of ABZ and both enantiomers of ABZSO. ABZSO and ABZSO(2) were the analytes recovered in plasma with ABZ and ABZSO present in H. contortus. ABZ was the analyte recovered at the highest concentration in H. contortus and abomasal mucosa, whereas higher concentrations of ABZSO were measured in abomasal fluid content. Only low concentrations of ABZ were detected in F. hepatica and bile, but markedly higher concentrations of ABZ were measured in liver tissue. ABZSO was the main molecule recovered in F. hepatica, plasma and bile samples collected from ABZ-treated sheep. The (+) enantiomer of ABZSO was recovered at a higher proportion in plasma (75%), bile (78%) and F. hepatica (74%) after ABZ administration to infected sheep.  相似文献   

20.
The antibody and lymphocyte responses to Fasciola hepatica were studied in rats. Infested rats were shown to produce antibodies against excretory-secretory (ES) products of adult flukes as early as the first week after infestation. Immunoblotting revealed fractions of ES products of adult flukes to which antibodies were progressively produced during the course of the infestation. Proliferation of peripheral blood lymphocytes, splenocytes and thymocytes when incubated with different mitogens (Concanavalin A (ConA) or Pokeweed mitogen (PWM) or different liver fluke antigens (metacercariae antigen (EM) or ES products of adult flukes) have been studied. In response to these mitogens or antigens, splenocytes were stimulated on the second and fourth weeks after infestation. Thymocytes were significantly activated by PWM on the second week but peripheral blood lymphocytes did not show any statistically significant response. Results obtained in antibody production, immunoblotting and lymphocyte proliferation suggested sequential releases of F. hepatica substances and the existence of common proteins between adult and juvenile parasite stages. Cellular and humoral responses observed in this work did not seem to confer a complete resistance to liver fluke primary infestation on the rat.  相似文献   

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