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1.
Immunoglobulins were analysed in the sera of pigs inoculated once with different numbers of Trichenella spiralis. Analyses for IgE were performed by homologous passive cutaneous anaphylactic (PCA) reactions and for IgG (H + L) by enzyme linked immunosorbent assay (ELISA).In the higher inoculation dose range (5,000–10,000 larvae) IgE production paralleled that of IgG (H + L). In the lower range (150,500 and 1,500 larvae) IgE production preceded IgG production in most animals.The possible significance of this finding for the early diagnosis of T. spiralis infections is discussed.  相似文献   

2.
The application of the enzyme-linked immunosorbent assay (ELISA) in the detection of Trichinella spiralis infections in pigs is presented. Two experiments using conventionally raised pigs infected with various numbers of T. spiralis larvae are described. Blood samples were collected for serological examination, prior to and at various days post infection (pi). At slaughter, on the 28th day pi, samples from the diaphragm were collected for isolation of muscle larvae by means of the digestion method. The results from these sera were compared with those from non-infected conventionally raised pigs. At day 28 pi, 21 out of 33 infected pigs showed positive ELISA results. In only two of those serologically positive animals were no larvae detected at slaughter. Of the 12 infected pigs with a negative ELISA result, only two harboured more than 3 larvae/g (the detection limit of trichinoscopy). Of the nine non-infected control animals, one had a false positive ELISA result. The significance of these findings in relation to slaughterhouse control is discussed. ELISA, therefore, presents an alternative to other detection methods for the control of T. spiralis infections in pigs.  相似文献   

3.
Rats readily become infected with Trichinella spiralis but are more resistant to T. nativa. We infected complement factor C6-deficient (C6?) rats and control (C6+) rats with T. spiralis and T. nativa to compare the effects of membrane attack complex on these parasites in vivo. The 2000 larvae infection dose per rat yielded 652 lpg (larvae per gram) in the C6? group and 608 lpg in the C6+ group with T. spiralis, whereas with T. nativa the corresponding figures were only 1.05 and 1.87 lpg. The difference between the Trichinella species was evident, but the infection intensity was unaffected by the C6 deficiency. When newborn larvae were incubated in C6-deficient and control rat sera for 24 h in vitro, no changes in viability were observed. Immunohistochemistry revealed that the musculature of cross-sectioned adults and certain stichocytes bound human complement factors C3, C8 and C9, but not C1q. Interestingly, the outermost layer of the cuticle and the newborn larvae did not show any binding activity. Similar findings were obtained with immunofluorescence microscopy of intact newborn larvae. These results indicate that both T. spiralis and T. nativa have efficient mechanisms to protect themselves against complement attack. The difference in infectivity for rats between the two species, however, is not due to a differential resistance to complement membrane attack complex.  相似文献   

4.
Blood from 2 buffalo harbouring Theileria organisms was inoculated into a splenectomized Ayrshire calf. The calf developed an infection which extended over a long period. The infection was transmitted to two cattle with Amblyomma gemma by transstadial transmission between the larvae and nymphs. Severe anaemia developed in these cattle and correlated with the parasitaemia. Schizonts morphologically characteristic of T. mutans were detected for short periods in the lymphoid cells of cattle infected by the ticks. The antigens and sera prepared from the cattle reacted with T. mutans sera and antigens in the indirect fluorescent antibody test. After recovery from the primary parasitaemia, the cattle had detectable organisms and antibodies to T. mutans for more than two years.  相似文献   

5.
The effects of simulatenous infection of pigs with Oesophagostomum spp. and Trichinella spiralis on the interpretation of the Enzyme-Linked Immunosorbent Assay (ELISA) for trichinosis were examined. Extinction values were observed from four groups of pigs. The first group acted as uninfected controls, the second was infected only with Oesophagostomum spp., the third with T. spiralis alone and the fourth by both nematodes.It was found that the pigs infected with T. spiralis could be differentiated from the others, but that those infected with both species had lower extinction values than the group with T. spiralis alone. The differences may be related to the numbers of T. spiralis larvae able to establish and develop into adults in the small intestine of the host. Those infected with Oesophagostomum spp. alone showed no rise in extinction values, and it was concluded that there was no cross-reaction in the ELISA between thos pecies and T. spiralis antigen.  相似文献   

6.
Normal rat peritoneal exudate cells adhere to new-born Trichinella spiralis larvae in the presence of specific antibodies produced during the course of an oral infection. After 24 hours incubation with the peritoneal cells and antibodies most of the larvae were killed. Heated immune serum had less activity. With normal serum no adherence was observed. In order to investigate the influence of antibodies on new-born larvae in vivo, larvae were pre-treated in vitro with immune serum and then inoculated intravenously into normal mice. After 30 days the yield of normal larvae was 50% of the number recovered in a control group infected with non-treated new-born larvae.  相似文献   

7.
Four methods employed in the diagnosis of trichinellosis [trichinoscopy, digestion method, immunofluorescence techniques and Enzyme-Linked Immunosorbent Assay (ELISA)] were compared by laboratories in eight countries of the European Economic Community. Material from 24 pigs infected with 10 000, 5000, 500, 150 and 0 T. spiralis larvae was examined during a period from 17 days to 12 weeks post infection. ELISA was more sensitive than immunofluorescence during the onser of the infection in groups in infected with higher numberts of larvae (1500, 5000 and 10 000 larvae). In general, however, results of both ELISA and immunofluorescence were comparable with regard to reliability. In pigs infected with a lower number of T. spiralis larvae both serological assays were more sensitive than the direct methods (trichinoscopy and digestion method).It was concluded that not enough evidence was available to suggest ELISA as an alternative to the direct methods for slaughterhouse control. Both the ELISA and the immunofluorescence technique may prove to be applicable for epidemiological surveys.  相似文献   

8.
Trichinella spiralis larvae establish chronic infections in skeletal muscles of immunocompetent hosts. Muscle infection is crucial to transmission and survival of the parasite in nature. Chronic infections by this highly immunogenic parasite are associated with modulation or escape from potentially destructive immune responses. This review summarizes our current knowledge of immunity to muscle infection with T. spiralis.  相似文献   

9.
When viable eggs of Taenia ovis were given orally to 1-week-old lambs, infection occurred only in those lambs that had been deprived of colostrum. When viable eggs were injected subcutaneously into 1-week-old lambs, no larvae developed at the injection site, and no resistance was stimulated against an oral challenge of T. ovis eggs given 11 weeks later. However, when eggs, oncospheres or developing cysticerci were subcutaneously injected into 16-week-old lambs, all grew at the injection site and stimulated a high degree of immunity to oral infection. Colostrum-derived antibodies against T. ovis apparently suppressed the immunizing potential of T. ovis eggs injected subcutaneously into neonatal lambs.  相似文献   

10.
The subcutaneous injection of viable eggs of Taenia hydatigena into neonatal lambs induced 100% protection against the development of viable T. hydatigena larvae from an oral challenge. However, contrary to some published results, no protection was induced against a simultaneous infection with eggs of T. ovis and Echinococcus granulosus.The short-acting partial resistance to oral infection with T. hydatigena eggs, transferred from infected ewes to their lambs, was not enhanced by hyperimmunization of the ewe. In the lamb, this resistance did not interfere with the development of subcutaneously injected T. hydatigena eggs into immature larvae, or with the consequent induction of resistance to an oral challenge with T. hydatigena eggs. The immunizing lesion regressed rapidly after treatment of lambs with Mebendazole, and after 6 months the lesions were negligible in both treated and untreated lambs.  相似文献   

11.
Four methods employed in the diagnosis of experimental porcine trichinellosis (trichinoscopy, digestion method, immunofluorescence and enzyme linked immunosorbent assay (ELISA)) were compared by eleven laboratories in the countries of the European Economic Community and Sweden. The aim of this study was to test the reliability of ELISA during the onset of T. spiralis infection. Material from conventionally raised pigs infected with 1500 or 10000 larvae was compared to uninfected controls at Day 17 and Day 21 post infection.The serological techniques gave higher percentages of positive results than the direct techniques. Specific antobodies could be demonstrated with ELISA at an earlier stage and at higher percentages than with the other methods. ELISA micro-assay was the most sensitive procedure.  相似文献   

12.
An immunofluorescent (IF) test for the serodiagnosis of Toxocara canis infections in puppies is described. Frozen sections of male adult T. canis worms were used as antigen.A group of seven puppies, 6 weeks of age, was infected orally with 10 000 embryonated T. canis eggs each. In the sera of all animals IF antibodies could be detected from approximately 4 weeks after infection onwards. Titers were detectable until the end of the observation period (22 weeks).Two puppies of the same age were infected with 30 000 or 50 000 embryonated T. canis eggs respectively. Positive IF results were also obtained in the sera of these pups from week 4 post infection (p.i.) onwards. No correlation between titer and initial number of egges administered was observed. Furthermore, no correlation was noticed between titer and number of adult worms recovered from the dogs. For comparison all sera were tested with the complement fixation (CF) test, using cuticle material of adult worms as antigen. Complement fixing antibodies could be detected in none of the serum samples.  相似文献   

13.
Trichinella is a food-borne parasitic zoonoses and human cases are still reported in Europe mainly due to the consumption of pig meat originating from small backyard farms. Infections originating from industrialized pig farming have not been reported for decades in Europe, due to control measures to prevent the transmission of Trichinella from wildlife by indoor housing and good management practices. Therefore, risk-based monitoring programs might replace individual carcass control in industrialized pig farming as described in EU legislation SANCO 2075/2005. Transmission of Trichinella species between wildlife and the risk that may pose to humans via consumption of contaminated pork meat has not been studied quantitatively. One pathway by which human trichinellosis can occur is the rat–pig–human route. To evaluate the transmission risk though this pathway the dose responses of rat, pig, and human were studied. Experimental T. spiralis infection was performed in rats with doses of as few as 10 parasites and the data set was analysed using a newly developed dose response model that describes larvae per gram (LPG). Experimental T. spiralis infection in pig was analysed in a similar way. Furthermore nine published outbreaks of human trichinellosis were analysed to determine the dose response in humans. The risk of human trichinellosis via the rat–pig–human transmission was simulated by the Monte Carlo method. A pair of female and male parasites representing the lowest infection pressure from the environment, led to the probability of human trichinellosis by consumption of 100 g of raw pork meat equal to 5% via the studied rat–pig–human pathway. In the absence of rodent control near the farm, a low infection pressure from wildlife presents a relatively high risk of human trichinellosis via consumption of uncooked pork meat.  相似文献   

14.
Flow cytometry analyses were used to evaluate the contribution of apoptotic and necrotic lymphocytes in the selected organs of Trichinella spiralis infected mice treated with phytohaemagglutinin-P (PHA-P). The Tunnel method was used to examine apoptosis in a cryostat section from the jejunum and masseter muscle. CFW mice (Groups I and II) were infected with 200 larvae of T. spiralis. PHA-P was administered intravenously at a dose of 10 mg/kg 24 h prior to infection in Group II mice only. Group III mice were treated with PHA-P without T. spiralis infection, and Group IV mice were untreated controls. The lymphocytes obtained from the spleen, mesenteric lymph nodes (MLN) and muscular inflammatory infiltration on 7, 14, 21, 28, 35, 42 and 60 days post infection (DPI) were incubated with the Annexin-V-Fluos Staining Kit (Roche). The cryostat preparation made from the jejunum and masseter muscle was evaluated using a fluorescence microscope. PHA-P administration stimulated apoptosis in the jejunal mucosa and in the muscular inflammatory infiltration. In Group I mice, infected with T. spiralis only, the highest percentage of apoptotic cells was found on 7 DPI in the spleen and in MLN, and on 14 DPI among the cells of the muscular inflammatory infiltration. The peak of the necrotic lymphocytes was found on 7 DPI in the spleen, on 28 DPI in MLN, and on 21 DPI in the cells of muscular inflammatory infiltration. In Group II mice, infected with T. spiralis and treated with PHA-P, the peak in apoptotic cells occurred on 7 DPI in the spleen and in the muscular inflammatory infiltration. The highest level of necrotic lymphocytes was observed only on 7 DPI in the muscular inflammatory infiltration. Percentage of necrotic lymphocytes in the spleen was the same and in MLN it was lower than in Group I (T. spiralis only). Moreover, the number of muscle larvae in mice treated with PHA-P (Group II) was lower than in Group I (T. spiralis only).  相似文献   

15.
Mast cell (MC) hyperplasia and activation are prominent features in Trichinella spiralis infection. Indeed a temporal correlation has been shown between the kinetics of intestinal mastocytosis, release of inflammatory mediators from MC, and adult worm loss, which constitutes a major component of the defense against T. spiralis infection. It is well known that during the intestinal phase of trichinellosis, muscle larvae (ML) and adult worms (AD) enter into contact with the host; however, interaction with MC may also occur during migration of newborn larvae (NBL). Therefore, it is plausible that antigens from these developmental stages could activate MC. We have previously demonstrated by in vitro assays that T. spiralis muscle larval (TSL-1) antigens activate MC through an Ig-independent mechanism leading to the release of histamine, MC protease 5, IL-4 and TNF alpha. In this work we evaluated whether total antigens from AD or NBL could activate unsensitized MC and we compared this activation with the activation seen when MC are stimulated with TSL-1 antigens. MC activation was also tested with affinity chromatography purified antigens from NBL using the monoclonal antibody CE-4 that recognizes NBL surface components. The results obtained in this study showed that AD total extracts and TSL-1 antigens induced the release of histamine but not β-hexosaminidase from unsensitized MC, suggesting a selective secretion of MC mediators. In contrast, NBL total extracts or purified NBL antigens did not induce the release of either histamine or β-hexosaminidase from MC. Interestingly, AD and ML are the stages that interact with the host during the intestinal phase of infection. The mechanisms involved in TSL-1 and AD activation of unsensitized MC may function together with other mechanisms of MC activation in host protection against T. spiralis.  相似文献   

16.
The influence of host genetics on the susceptibility to primary Trichinella spiralis infection has been extensively studied in a mouse model, but has not been clarified for rats. Analyses of interstrain and intrastrain genetic variation in response to infectious agents could be beneficial not only for elucidating the genetic basis of host resistance/susceptibility, but for revealing immune response mechanisms as well. The aim of this study was to analyse interstrain differences in worm burdens and cytokine production between Albino Oxford (AO) and Dark Agouti (DA) rats in muscle phase of T. spiralis infection. Clear strain-dependent variation was observed in the number of T. spiralis larvae per gram (lpg) of muscle tissue where values for DA rats (626.7 ± 171 lpg) vastly exceeded those found in AO rats (49.8 ± 25.9 lpg, p < 0.001). Differences between the strains were also noticed in key cytokine levels. In infected AO rats, the cytokine production remained in favor of Th1 type response, while infected DA rats showed a shift towards a Th2 type response. The level of regulatory IL-10 was significantly increased only in T. spiralis infected DA rats. Our results provide evidence that DA rats express higher susceptibility to T. spiralis infection in comparison to AO rats with respect to muscle larvae burden. The infection in DA rats was accompanied by the production of anti-inflammatory cytokines, while the response of AO rats was characterized by a proinflammatory type of immune response.  相似文献   

17.
Murine forestomach carcinoma (cell line MFC), ascitic hepatoma (cell line H22) and sarcoma (cell line S180) solid tumor models were used to test the anti-tumor effect of Trichinella spiralis in vivo. Mice previously infected by oral administration of 400 viable T. spiralis larvae per mouse for 7 days were grafted with various solid tumor cell lines. Other groups of tumor-bearing mice were given caudal vein injection of crude extracts of adult and newborn larvae at 17.5, 35.0 or 70.0 mg kg?1. These treatments to inhibit tumor growth were dose-dependent (p < 0.05). The anti-proliferative activity of crude T. spiralis extract was examined in vitro at 0.035, 0.070 or 0.140 mg ml?1 using MFC, H22, S180, human chronic myeloid leukemia cell line (K562) and hepatoma cell line (H7402), tumor cell proliferation in vitro was measured by methyl thiazolium stain and was inhibited in dose-dependent manner (p < 0.05). At the same doses, crude T. spiralis extracts induced apoptosis of K562 and H7402 as detected by DNA fragmentation. Cell cycle analysis indicated that crude T. spiralis extracts, at 0.140 mg ml?1, arrested the cell cycle of K562 and H7402 in G1 or S phase. It is concluded that T. spiralis contains anti-tumor active agent.  相似文献   

18.
In order to identify those bacterial antigens which might be involved in immunity against ovine footrot, antisera were raised in sheep to 6 proteins in the outer membrane complex (OMC) of one strain of Bacteroides nodosus. Examination of the specificity of these antisera by Western blotting, crossed immunoelectrophoresis (XIEP) and IEP, revealed that they recognized the homologous OMC protein, but did not precipitate either undenatured pili or OMC, nor could they agglutinate the homologous bacteria. In contrast, anti-OMC and anti-pili sera could precipitate OMC or pili respectively, and agglutinate whole bacteria. Subsequent analysis of these sera against 5 strains of B. nodosus from different serogroups revealed that Proteins 1, 3 and 4 had a similar antigenic structure in all strains examined. The reactivity of anti-pili sera was restricted to homologous bacteria whereas anti-pilin sera (raised against denatured pili) also reacted with pilin from 2 of 3 heterologous strains. However, none of the patterns of staining or absorption of any of these sera matched the spectrum of cross-protection afforded by vaccination of sheep with B. nodosus strain 198 cells. The results question the role of individual OMC proteins in cross-protective immunity and may imply that interactions between several bacterial components are involved in the phenomenon.  相似文献   

19.
Recently, there has been interest in programs that certify pork production practices that minimize the risk of exposure of pigs to Trichinella spiralis. Certification might be useful for reducing the risk of human trichinellosis from pork in Argentina, but more information is needed on pig production practices and sources of Trichinella infection in Argentinian pigs. In this study, 21 pig farms were assessed for Trichinella infection including some farms using total and partial confinement management, and others with pigs raised exclusively outdoors. A total of 3224 muscle samples were collected from pigs raised on these farms and tested to determine the presence of T. spiralis larvae by artificial digestion. Serum samples from the same 3224 pigs were tested for antibodies to T. spiralis by ELISA. For each farm, a questionnaire was completed summarizing information about management factors and this information was used to assess risk factors for exposure of T. spiralis. Based on the results, pigs raised outdoors were more likely to be infected than pigs raised in total or partial confinement (p ≤ 0.05). Pigs fed waste products containing meat were 12.5 times more likely to be infected than pigs not fed waste containing meat (p < 0.01). The role played by rats in transmission of Trichinella is unclear; however, on farms with evidence of wild animals and access of pigs to wildlife carcasses, the prevalence of Trichinella infection was significantly higher. All pigs raised under good hygienic and sanitary conditions were negative for Trichinella infection by both artificial digestion and ELISA.  相似文献   

20.
Vaccination with irradiated Trichostrongylus colubriformis larvae produced a high level of immunity, as judged by faecal egg counts and worm burdens following challenge with normal larvae, in nine of ten sheep aged 10 months. In lambs aged 3 months, vaccination was less effective. Some lambs developed partial immunity, but others did not respond.Serum levels of antibodies to T. colubriformis acetylcholinesterase reflected the extent of antigenic exposure rather than the degree of immunity acquired, and there was no evidence that the unresponsiveness of the lambs was due to a deficiency in antibody production.Unresponsiveness was not associated with the numbers of circulating lymphocytes, monocytes or granulocytes, or with the numbers of mast cells, eosinophils and neutrophils at the site of infection. However, there were many globule leucocytes in the intestinal mucosa of adult sheep which were resistant to challenge infection. On the other hand, few of these cells were found in vaccinated lambs which generally gave a poor response to challenge.  相似文献   

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