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1.
Serum antibody responses in sheep naturally or experimentally infected with Echinococcus granulosus and/or other larval cestodes were examined using an enzyme-linked immunosorbent assay (ELISA) with various antigens prepared from sheep hydatid cyst fluid ( SHCF ). Serum donors included: sheep experimentally infected with E. granulosus and their age-matched non-infected controls; sheep experimentally infected with other helminth parasites; sheep naturally infected with E. granulosus both from Tasmania and the Australian mainland; sheep from Tasmania naturally infected with larval cestodes other than E. granulosus; and naturally reared sheep completely free from infection with larval cestodes. Attempts were made to eliminate serological reactions which were not specific for E. granulosus by using a series of antibody affinity chromatography steps to deplete crude SHCF antigen; these included adsorption with a monoclonal antibody, 3EgH 29-2, removal of host IgG using rabbit anti-sheep IgG antibody, and removal of antigens which bound non-specifically to normal sheep immunoglobulin. The final affinity-depleted antigen product was designated AD SHCF . Specific serological reactivity in infected sheep was very low. Affinity depletion of SHCF using 3EgH 29-2 did not appear to increase the specificity of serological diagnosis of E. granulosus infection when experimentally infected sheep were compared with their non-infected controls provided the latter were age-matched with experimental animals. The other affinity adsorption steps significantly reduced non-specific background binding to antigen by normal sheep serum. Despite this reduction in background in the ELISA, only low levels of antibody could be detected in naturally-infected sheep.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

2.
Praziquantel is a new type of acylated isoquinoline-pyrazine. A single, low oral or subcutaneous dose of the compound is reliably effective against all tested juvenile and adult cestodes in cats, dogs and sheep. Praziquantel is the first cestodicide which is also effective on bile duct cestodes. In cats and dogs, 5 mg praziquantel per kg is completely effective on all stages of Taenia hydatigena, T pisiformis, T ovis, T taeniaeformis, Dipylidium caninum, Mesocestoides corti, Echinococcus multilocularis and E granulosus. Because of its very wide therapeutic index praziquantel is thus particularly suited for eradication programmes, eg, echinococcosis.  相似文献   

3.
Highly effective recombinant vaccines have been developed against the helminth parasites Taenia ovis, Taenia saginata and Echinococcus granulosus. These vaccines indicate that it is possible to achieve a reliable, high level of protection against a complex metazoan parasite using defined recombinant antigens. However, the effectiveness of the vaccines against the taeniid cestodes stands in contrast to the more limited successes which characterise attempts to develop vaccines against other platyhelminth or nematode parasites. This review examines the features of the host-parasite relationships among the taeniid cestodes which have formed the basis for vaccine development. Particular consideration is given to the methodologies that have been used in making the cestode vaccines that might be of interest to researchers working on vaccination against other helminths. In developing the cestode vaccines, antigens from the parasites' infective larval stage contained within the egg (oncosphere) were identified as having the potential to induce high levels of protection in vaccinated hosts. A series of vaccination trials with antigen fractions, and associated immunological analyses, identified individual protective antigens or fractions. These were cloned from cDNA and the recombinant proteins expressed in Escherichia coli. This strategy was independently successful in developing vaccines against T. ovis and E. granulosus. Identification of protective antigens for these species enabled rapid identification, cloning and expression of their homologues in related species and thereby the development of effective vaccines against T. saginata, E. multilocularis and, more recently, T. solium. The T. saginata vaccine provides an excellent example of the use of two antigen components, each of which were not protective when used individually, but when combined they induce a reliable, high level of protection. One important contributing factor to the success of vaccine development for the taeniid cestodes was the concentration on studies seeking to identify native host-protective antigens, before the adoption of recombinant methodologies. The cestode vaccines are being developed towards practical (commercial) application. The high level of efficacy of the vaccines against T. solium cysticercosis and hydatid disease suggests that they would be effective also if used directly in humans.  相似文献   

4.
A survey of the cestode infections of 304 dogs from 134 properties in the Albany area of Western Australia was performed. Purgation was induced by oral administration of arecoline and the purge examined for cestodes. The cestodes found and their infection rates were: Dipylidium caninum 16.4%; Taenia spp 36.5%; T. ovis 8.9%; T. hydatigena 15.1%; T. pisiformis 15.1%; T. serialis 2.3%; Echinococcus granulosus 0.7%; Questionnaires completed on 133 of the 134 properties at the time the dogs were purged showed that:– 73.6% of farmers were feeding raw sheep-meat and 24.8% were feeding raw offal to their dogs; dogs were treated on a regular basis with a cestocide on 23.3% of properties; dogs were allowed to roam on 21.8% of the properties and stray dogs were considered prevalent on 23.3% of properties.
Suggestions for control of Cysticercus ovis are made based on an interpretation of the significance of these findings.  相似文献   

5.
Two hundred and eighty foxes necropsied over a 4-year period harboured cestodes in the following order of prevalence: Taenia pisiformis, Echinococcus granulosus, T. hydatigena, T. multiceps and Dipylidium caninum. The nematodes Uncinaria stenocephala, Toxocaracanis and Toxascaris leonina, were also found. These findings are discussed in the light of other surveys.  相似文献   

6.
Extract

As no statistical surveys have previously been undertaken, factual knowledge of the incidence and specific epidemiological problems of the cestodes affecting domestic and wild animals in New Zealand is limited. This permits a certain degree of speculation (hence the title of this paper), on the extent of problems of control and the methods which may have to be adopted against Echinococcus granulosus, Taenia hydatigena, T. ovis, and Multiceps multiceps.  相似文献   

7.
Groups of dogs reared free of both nematodes and cestodes were infected with Taenia hydatigena, Taenia pisiformis or Echinococcus granulosus. After infections with the Taenia spp became patent, dogs were purged to remove the worms. They were later reinfected and the second infections again removed by purging after patency. A group of 3 uninfected worm free dogs was kept as age-matched controls. The dogs were bled at intervals of 5 days and their serums tested for antibodies using the enzyme-linked immunosorbent assay (ELISA) with excretory/secretory (ES) antigens collected during in vitro incubation of evaginated scoleces (scolex ES antigen) and oncosphere antigens. Antibodies to scolex ES antigen were detected by 3 weeks after infection with each cestode species whereas antibodies to oncosphere antigen were not detected until about one week after eggs were found in the faeces of the infected dogs. Antibody responses to both oncosphere and scolex ES antigens decreased rapidly following removal of the worms by purging. Uninfected control dogs were invariably negative to both oncospheral and scolex ES antigens. There were cross-reactions between the serums from dogs infected with T. pisiformis and T. hydatigena when tested with scolex ES antigens, but oncospheral antigens showed a high degree of species specificity. Scolex ES antigens from E. granulosus were compared with those prepared from T. hydatigena and T. pisiformis for their ability to discriminate between antibodies in serums collected from dogs 31 and 32 days after infection with 100,000 protoscoleces of E. granulosus or dogs infected with Taenia spp.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

8.
A cross-sectional study to determine the prevalence of bovine cysticercosis and hydatidosis was conducted from October 2007 to March 2008 in cattle slaughtered at the Jimma municipal abattoir. Cyst distribution and viability of bovine cysticercosis and hydatidosis were also determined. A total of 512 carcasses were inspected of which 15 (2.93%) and 161 (31.44%) were infected with Taenia saginata metacestodes and hydatid cysts, respectively. From a total of 109 cysticerci collected from infected carcasses, 47 (43.12%) were viable. The anatomical distribution of the cysticerci was, shoulder muscle (39.5%), heart (33.9%), neck muscle (13.8%), tongue (10.1%), masseter muscles (1.8%) and diaphragm (0.9%). Of the 1171 hydatid cysts collected 223 (19.0%) were fertile, 505 (43.1%) sterile, 49 (29.8%) calcified and 94 (8.0%) contained pus. A greater proportion of fertile cysts were found in the lungs than in other organs. It was concluded that these zoonotic cestodes deserve due attention to safeguard public health, and that further studies are needed on genotyping, epidemiology and public health importance of Echinococcus granulosus in the study area.  相似文献   

9.
Serum antibody responses in feral or domesticated dogs naturally infected with Echinococcus granulosus or/and other common helminths were examined in an enzyme-linked immunosorbent assay (ELISA) using antigens prepared from E. granulosus protoscoleces or oncospheres. The ELISA using the protoscolex antigen was optimised with serums from experimental dogs monospecifically infected with E. granulosus or other helminth parasites, and helminth-free dogs. Anti-protoscolex antibody was detected in 16 of 22 (72.7%) serums from feral dogs with E. granulosus burdens ranging from 300 to 302,600 worms per dog. Seven serums from feral dogs which did not harbour E. granulosus at autopsy but which originated from an endemic hydatid region were tested using protoscolex antigen, and 1 serum gave a positive reaction. One hundred and two serums from dogs known never to have been infected with E. granulosus all gave negative reactions to protoscolex antigen. The sensitivity of the ELISA test proved to be superior to that which has been achieved by arecoline purging as a method of diagnosis for E. granulosus infection in dogs. For use of the assay in hydatid control or eradication campaigns, its sensitivity can be increased by choosing a lower absorbance discrimination value above which serums are regarded as having positive reactions. However, this does introduce positive reactions of some serums from dogs infected with helminths other than E. granulosus. In further development of the assay, use of defined recombinant antigens may improve both sensitivity and specificity.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

10.
为建立特异性和敏感性高的检验犬细粒棘球绦虫感染的方法。用细粒棘球绦虫(简称,Eg)成虫抗原分别免疫兔和绵羊,收集高免血清,纯化的高免抗体。依据抗体夹心ELISA工作原理,以兔抗体包被,检测感染Eg、不同犬带科绦虫的实验犬和空白犬粪样,绵羊抗体扑捉抗原,HRP标记兔抗绵羊IgG(1∶8 000)催化显色,用酶标仪测定OD 405nm吸光度,用以确定其特异性和敏感性。试验结果表明,敏感性为82.69%(43/52),特异性为85.88%(140/163);粪抗原在感染细粒棘球绦虫16d后可检出,最低抗原浓度为9.7ng/mL即犬感染5条成虫时可检测出阳性。该检测方法具有较好的特异性和灵敏性,为进一步研制检测细粒棘球绦虫虫体抗原ELISA检测试剂盒奠定了基础。  相似文献   

11.
A study on the prevalence and seasonal incidence of cestode parasite infections of sheep and goats was carried out in eastern Ethiopia for 2 years (May 2003-April 2005). During this period, viscera including liver, lungs, heart, kidneys and the gastro-intestinal tract were collected from 655 sheep and 632 goats slaughtered at four abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga. At the abattoirs the abdominal, thoracic and pelvic cavities as well as the muscle surfaces of all animals were visually examined for the presence of larval (cystic) stages of cestode parasites. The viscera were transported within 24 h to the parasitology laboratory of Haramaya University and were examined for larval and adult cestodes following standard procedures. The most prevalent metacestodes (larval cestodes) were Cysticercus ovis (Taenia ovis), Cysticercus tenuicollis (T. hydatigena) and hydatid cysts (Echinococcus granulosus). In sheep, the overall prevalence was 26% for C. ovis, 79% for C. tenuicollis, and 68% for hydatid cysts. Similarly, for goats, the corresponding prevalence was 22%, 53% and 65%, respectively. The difference between sheep and goats in prevalence of C. tenuicollis was significant. The high prevalence of hydatid cysts in both sheep and goats indicates that cystic echinococcosis/hydatidosis is a public health problem in these regions which requires implementation of control measures, including public health education, strict meat inspection and control of stray dogs. The results of the survey also implies that infections of small ruminants with these metacestodes are responsible for condemnation of substantial quantities of affected organs and muscles and therefore of direct economic importance. Intestinal infections with adult tapeworms of Moniezia expansa, Avitellina centripunctata and Stilesia globipunctata, and bile duct infections with Stilesia hepatica were also common in both sheep and goats. In sheep, the overall prevalence of these tapeworms were 61%, 20%, 24% and 39%, respectively. Similarly, the overall prevalence of these parasites in goats was 53%, 21%, 27% and 36%, respectively.  相似文献   

12.
A cross-sectional survey was conducted to estimate the prevalence of Echinococcus multilocularis and E. granulosus infections in domestic dogs and cats from Germany and other European countries. Faecal samples of 21,588 dogs and 10,650 cats routinely submitted to a private veterinary laboratory between June 2004 and June 2005 were examined using the ZnSO(4)-NaCl flotation method. Taeniid eggs were detected in 54 (0.25%) and 37 (0.34%) of the canine and feline faecal samples, respectively. Taeniid eggs were separated and subjected to a DNA preparation and a modified two-step PCR for the detection of Echinococcus spp. based on mitochondrial 12S rRNA genes. PCR products from Echinococcus-negative but cestode-positive reactions were cloned and sequenced to determine the Taenia species. E. multilocularis DNA was specifically amplified in 43 (0.24%) and 25 (0.23%) of the samples from dogs and cats, respectively. E. granulosus DNA was not detected in any sample, while, E. multilocularis-positive samples were detected in dogs from Germany only, those of cats originated from Germany, Denmark and The Netherlands. The prevalence of E. multilocularis egg-positive canine samples was significantly higher in southern (0.35%) than in northern Germany (0.13%). In contrast, no significant regional difference was observed in cats from Germany. Taeniid eggs from Echinococcus-negative samples and from a few samples with macroscopically detected Taenia sp. proglottids were identified as eggs of T. crassiceps (n=8), T. martis, T. serialis, T. polyacantha, T. taeniaeformis and T. pisiformis in dogs (n=1 of each) and T. taeniaeformis (n=11) in cats. The spectrum of cestodes detected in domestic dogs and cats indicate the consumption of small rodents as infection source. The high proportion of E. multilocularis-positive samples, suggest domestic dogs and cats as a possible source of E. multilocularis infection for humans.  相似文献   

13.
In order to monitor the progress of New Zealand's hydatids eradication campaign, a specific, serological, diagnostic test is required to identify infected sheep. An indirect haemagglutination test, using pyruvic aldehyde-stabilized sheep erythrocytes as the antigen carrier, was developed for the serodiagnosis of larval cestode infections of sheep. Using cyst fluid from Echinococcus granulosus, Taenia hydatigena and T. ovis as the antigens in this test, it was shown that the larval cestode species, responsible for an infection in sheep harbouring a single specific infection, could be identified by the higher titre given with the homologous antigen, in comparison to that given with the heterologous antigens. Sera of sheep infected with two or more species were also tested by this method, and the only specific infections to be diagnosed by differential titres were those due to the presence of live E. granulosus cysts. These antigens cannot be used for the diagnosis of specific larval cestode infections in the field because of the cross-reactivity between cyst fluids. However, the test did show that infection with larval cestodes could be diagnosed on a non-specific basis.  相似文献   

14.
Echinococcus granulosus is an important zoonotic infection of dogs. The purpose of the present study assessed the performance of two laboratory diagnostic methods with arecoline purgation and necropsy in infected dogs. In total 65 dogs were successfully experimentally infected with protoscoleces of E. granulosus from ovine infection. At 14-34 days post-infection groups of dogs were purged with arecoline hydrobromide and then necropsied. Faecal samples were tested at weekly intervals by coproantigen ELISA and coproPCR. The necropsy infection rate with E. granulosus was 89.2 per cent. Only 43 per cent of dogs were successfully purged after one arecoline dose; this percentage increased to 76.9% for two doses of arecoline purgation. E. granulosus coproantigen was detected by coproELISA in 82.8% of faeces. The positive and negative predictive values for coproantigen ELISA were 96 and 44.4% respectively. E. granulosus DNA was detected in pre-patent faecal samples by coproPCR in 25.9% of dogs. These results indicate that coproELISA is more sensitive than arecoline purgation for the detection of pre-patent E. granulosus infection in dogs. CoproPCR detected E. granulosus DNA in dog faeces by 21 days post-infection before egg production.  相似文献   

15.
Cyst fluid antigens of Echinococcus granulosus, Taenia hydatigena and T pisiformis were examined by electrophoresis using homologous and heterologous hyperimmune rabbit sera to these antigens. While arc 5 forming antibodies were identified in sera from rabbits immunised with E granulosus and T hydatigena cyst fluids, antibodies responsible for forming precipitating antigen B band were detected in rabbit antisera to E granulosus, T hydatigena and T pisiformis antigens. T hydatigena cyst fluid appears to contain antigen similar to E granulosus antigen 5 and probably antigen B while T pisiformis cyst fluid has mainly an antigen close to hydatid antigen B.  相似文献   

16.
Immunodiagnosis in sheep presents problems of sensitivity and specificity, limiting its applicability in surveillance systems. The objective of this study was to develop a sensitive, specific and accessible technique for diagnosing cystic echinococcosis in naturally infected sheep and to evaluate the validity of necropsy as a reference test. A total of 247 sheep were studied at slaughterhouses, confirming the parasitological diagnosis with histology. Serum was processed with enzyme immunoassay (EIA) using three antigen preparations: total hydatid liquid (LHT), purified fraction of LHT (S2B) and purified lipoprotein (B). Western Blot (WB) was used as a control. EIA proved effective for differentiating Echinococcus granulosus from larval stage of Taenia hydatigena and intestinal cestodes in all three antigen preparations. Serums from macroscopically negative sheep were reactive to EIA and positive with WB. In the whole flock, sensitivity was 89.2% for LHT, 80.0% for S2B and 86.4% for B. Sensitivity in lambs was 78.6% for LHT, 75.0% for S2B and 64.3% for B. Macroscopic diagnosis at the time of slaughter was found to have limitations as a reference test for immunodiagnosis of cystic equinococcosis in sheep, so it was necessary to include histology and WB as reference tests. LHT was the antigen preparation of greatest value and EIA proved to be a sensitive and specific technique, adequate for surveillance systems and for evaluating control programmes.  相似文献   

17.
Proteins present in oncospheres and on the surface of living protoscoleces of Echinococcus granulosus were radioiodinated by the lodogen technique and immunoprecipitated with sera from dogs with E granulosus infection and several categories of control sera. Analysis of immunoprecipitates was performed using sodium dodecyl-sulphate polyacrylamide gel electrophoresis to identify antigenic protein components specific for E granulosus. Sera from dogs with E granulosus infection identified antigenic proteins of around Mr 37,000, 30,000 or 22,000 in oncospheres, and proteins of around Mr 70,000, 43,000, 36,000, 27,000 (triplet), 20,000 or 14,000 on the surface of protoscoleces. These antigens appear to be both species- and stage-specific and may be useful for serological discrimination between 'current' and 'recent past' prepatent and patent E granulosus infections in dogs.  相似文献   

18.
The effect of isatin on the E. granulosus cyst was studied. NMRI mice, which were infected with E. granulosus of sheep origin, were treated daily with isatin at a dose of 50 mg kg-1 for 18 days. Ultrastructural damage was observed in the treated cysts, including accumulation of lamellar stacks, electron-dense granules, autophagosomes and lipid vesicles. Moreover, a biochemical study showed an inhibition of alkaline phosphatase activity, with a decrease in carbohydrate storage and an increase in acid phosphatase activity. In spite of the short duration of the treatment, the results obtained allowed us to conclude that isatin acts on E. granulosus cysts. This activity appears as a process of degeneration linked to the alkaline phosphatase inhibitory effect of isatin.  相似文献   

19.
A survey was carried out in Catalonia, Spain to determine the prevalence of parasitic helminths infesting the digestive tract of nocturnal raptors (Strigiformes). One hundred birds belonging to six owl species were examined. The number of birds examined ranged between three and 30. The overall level of infestation was 65% and the most frequent helminths present were nematodes, followed by trematodes, cestodes and acanthocephalans. Strigiformes showing the highest levels of infestation were little owls (Athene noctua), 86.7% of which were infested. Helminths with the highest prevalence were Synhimantus spp., intestinal capillarids, Brachylaima spp., cestodes and Centrorhynchus aluconis.  相似文献   

20.
Echinococcus granulosus (E. granulosus) infection was studied in 151 dogs in two regions of Morocco: 68 dogs in the northwest (Loukkos) and 83 dogs in the southwest (Tiznit). The mean prevalence rates of echinococcosis in dogs were 58.82% (46.23-70.63%) in Loukkos and 55.42% (44.10-66.34%) in Tiznit and the mean abundances of E. granulosus per dog were 75 (59-93) and 547 (504-595), respectively. The mean abundance of E. granulosus in dogs was fitted to a negative binomial distribution by the maximum likelihood techniques to define parameters. E. granulosus was aggregated in dogs in the two regions. The prevalence of infection and the abundance of E. granulosus in dogs were fitted to mathematical models in order to determine if the parasite population is partly regulated by definitive host immunity. The best fit was obtained with the models assuming the presence of immunity. The mean time of exposure to infection was similar in the two regions and ranged from 8 months to about 2 years. The infection pressures (number of E. granulosus) obtained per dog each year were 65 (8-294) in Loukkos and 476 (316-886) in Tiznit. The proportion of dogs susceptible to infection was still high along the life of the dogs in Loukkos, while it was not different from zero in old dogs of Tiznit.  相似文献   

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