Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Echinococcus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 991 records · Page 55Linked to original sources

Experimental infection of larval Echinococcus multilocularis in the rodent brain as a model for cerebral alveolar echinococcosis.

Experimental infection of larval Echinococcus multilocularis in the rodent brain was attempted to establish a murine model for cerebral alveolar echinococcosis. Balb/c mice and jirds were injected intracranially with 10% of a homogenated hydatid cyst mass. Small cystic larvae were observed macroscopically in the cranial cavity 1, 2 and 5 months post-infection in both mice and jirds. Some larval cysts from both rodents contained mature or immature protoscoleces. In mice, the laminated layer was found in the lateral ventricle 2 months post-infection but without protoscoleces. At five months post-infection, larger larval cysts were found in the cranial cavity of a mouse, which also demonstrated partial palsy of the legs. A laminated layer with mature protoscoleces was observed in the third ventricle and the mouse also harboured, in the left lung, a larval cyst containing protoscoleces surrounded by lymphocytes. Jirds were also found to be infected with metacestodes in the cranial cavity, but neither unusual behaviour nor establishment of cysts inside the brain was observed in jirds during the course of infection.

Animals↗

Observations on the suitability and importance of the domestic intermediate hosts of Echinococcus granulosus in Uttah Pradesh, India.

The present study investigated the suitability and importance of buffaloes, camels, sheep, goats and pigs in maintaining the life-cycle of Echinococcus granulosus in Aligarh, India. A total of 565 (36%) of 1556 buffaloes, 20 (2%) of 1208 goats, 5 (1%) of 559 pigs, 6 (6%) of 109 sheep and two of three camels were found to harbour hydatid cysts. The frequency distribution of the hydatid cysts in each intermediate host species was over-dispersed and in buffaloes cyst fertility increased with increasing cyst size. Of 2171, 95 and four buffalo, goat, and camel cysts examined 327 (15%), two (2%) and three cysts respectively were fertile. No pig or sheep cysts were found to contain protoscoleces. The unfenced buffalo abattoir and the large number of dogs allowed access to the abattoir coupled to the number of buffalo slaughtered in comparison to the other potential hosts, indicates that the buffalo is the most significant host for maintaining the life-cycle of the parasite in this area of India. Applicable control measures for the region are suggested.

Abattoirs↗

The role of native domestic animals in the dissemination of Echinococcus infection among dogs in the state of Kuwait.

Infection with hydatid cysts of domestic animals slaughtered by private individuals and at the Government Central Slaughterhouse is recorded. Both fertile and non-fertile cysts were seen in the infected animals. The home slaughtered sheep seems to play an important role in the dissemination of the parasite and the life cycle of Echinococcus granulosus in the State of Kuwait is assumed to be sheep--dog--sheep.

Animals↗

Biochemical profiles of hydatid cyst fluids of Echinococcus granulosus of human and animal origin in Libya.

A comparative study on the biochemical parameters in hydatid cyst fluids of sheep, goats, camels, cattle and human cystic forms of Echinococcus granulosus has been made in Libya. Quantitative variations in the levels of sodium, potassium, calcium, cholesterol, glucose, urea, creatinine and gamma glutamyl transpeptidase (gamma GT) were found in the cystic fluids of different host origins although these differences were statistically insignificant compared with the hydatid fluids of sheep. However, the concentration of triglycerides and proteins were significantly elevated in the cyst fluids of sheep compared with the other fluids studied. Similarities in the biochemical composition of different hydatid cyst fluids suggest the existence of sheep strains of E. granulosus in human and other domestic animal intermediate hosts in Libya.

Animals↗

Simulating strategies for control of Echinococcus granulosus, Taenia hydatigena and T. ovis.

A deterministic model to compare various control strategies for parasites having two hosts is presented. When applied to Echinococcus granulosus, Taenia hydatigena and T. ovis, the model shows that maximum progress would be achieved when both the definitive and the intermediate host are treated simultaneously. This type of model may prove of value in studies on the control of other two-host parasites.

Animals↗

Epidemiological analysis of factors influencing rate of progress in Echinococcus granulosus control in New Zealand.

The factors influencing the rate of progress in Echinococcus granulosus control in New Zealand were analysed by hydatid control area using stepwise multiple regression techniques. The results indicated that the rate of progress was related positively to initial E. granulosus prevalence in dogs and the efficiency with which local authorities implemented national control policy, and negatively to the Maori proportion in the local population and the number of dogs per owner. Problems in analysis of the New Zealand data are discussed and improved methods of monitoring progress in hydatid disease control programmes are described.

Animals↗

The lethal effect of mebendazole on secondary Echinococcus granulosus, cysticerci of Taenia pisiformis and tetrathyridia of Mesocestoides corti.

Oral administration of mebendazole at a rate of 1 g/kg feed (approximately 50 mg/kg body weight/day) for 14 days killed mature and immature cysticerci of Taenia pisiformis in rabbits, and multiplying tetrathyridia of Mesocestoides corti in mice. Progressive degrees of parasite damage caused by mebendazole treatment could be assessed by histological examination of calcereous corpuscles. A single subcutaneous injection of 10 percent mebendazole in carrier, at a rate of 100 mg/kg body weight, resulted in the death of all M. corti tetrathyridia in mice within 4 weeks, but the drug in saline was slowly mobilized and was relatively ineffective. Neither subcutaneous injections of mebendazole in saline or in carrier could kill cysticerci of T. pisiformis within 5 weeks, but the drug in carrier was effective after several months. Mebendazole in saline was effective when injected intraperitoneally, but adhesions often resulted from this route of administration. Echinococcus granulosus protoscoleces administered to mice by intraperitoneal injection were rapidly encapsulated by host lymphoid cells. The vesiculating protoscoleces were all contained within a fibrous capsule for more than 2 months after infection, but by 4 months almost all had grown free of the host reaction. Treatment of the encapsulated protoscoleces with mebendazole in feed for 14-21 days caused collapse of the outer cysts and death of the germinal membrane of all but the innermost protoscoleces. Six weeks later, however, cysts had regrown from surviving germinal tissue and a further treatment with mebendazole in feed for 14-21 days again did not destroy all germinal cells. Treatment of the 4-month-old scoleces with mebendazole in feed for 14 days caused all cysts to collapse and destroyed practically all E. granulosus germinal tissue. Three subcutaneous injections of mebendazole at fortnightly intervals, of drug in saline at 500 mg/kg body weight, or in carrier at 100 mg/dg body weight, were required in order apparently to kill all secondary cysts of E. granulosus. Host lymphoid cells were not able to traverse the laminated membrane of either untreated or collapsed cysts, and it has been shown that only a small amount of living germinative tissue is required to produce a new E. granulosus cyst. These factors could contribute to the relative ability of E. granulosus cysts to recover from mebendazole treatment, compared with cysticerci or tetrathyridia. The effectiveness of mebendazole thus seemed to depend on the formulation of the drug and its route of administration. Mebendazole is probably the first anthelmintic to have a lethal effect on larval cestodes. When applied orally there do not appear to be any adverse effects due to treatment.

Administration, Oral↗

Population dynamics in echinococcosis and cysticercosis: economic assessment of control strategies for Echinococcus granulosus, Taenia ovis and T. hydatigena.

An official control programme against Echinococcus granulosus and Taenia hydatigena has been in operation in New Zealand for more than 28 years and against Taenia ovis for more than 18 years. This unique effort to control three metazoan parasites at the same time has led to a change from endemic to extinction status for E. granulosus but only a change from hyperendemic to endemic status for T. hydatigena and T. ovis. This has presented problems in determining the most cost-effective future control strategies. To facilitate this, a benefit/cost analysis of 20 options for the combined control of E. granulosus, T. hydatigena and T. ovis in New Zealand was undertaken. This showed that for E. granulosus a future change from the current non-targeted to a targeted approach is strongly indicated. For T. ovis 6 options were cost-effective using a discount rate of 10%. These were (1) a targeted control package using a vaccine in the non-targeted attack phase; (2) a targeted control package using a larvicide in the attack phase; (3) the transfer of all losses due to and responsibility for the control of T. ovis to the producer who administers a larvicide to sheep to be killed for dog food; (4) the transfer of all losses due to and responsibility for the control of T. ovis to the producer who administers praziquantel every 6 weeks to dogs; (5) and (6) two options involving the discontinuation of control. Control of T. hydatigena was assumed to be an incidental outcome of the policies for the other two parasites.

Animals↗

Assessment of monoclonal antibodies to Echinococcus granulosus antigen 5 and antigen B for detection of human hydatid circulating antigens.

Four monoclonal antibodies (MAb) to Echinococcus granulosus Antigen 5 (Ag5) and Antigen B (AgB) were assessed in an enzyme-linked immunosorbent assay (ELISA) for detection of circulating antigens (CAg) in sera of human patients with E. granulosus infection. Around 5.5-8% of 200 sera from 42 surgically proven hydatid patients contained detectable CAg by individual MAb. The combined detection rate for CAg, using four MAb, was 19% (38/200). Although hydatid CAg was detected by MAb in at least one serum sample from 21 of 42 patients, some patients remained negative in the assay regardless of the time when serum samples were taken (pre- or post-operatively), or of the continuing presence of hydatid cysts, their location or fertility. In addition, it was observed that the binding capacity of MAb for sheep hydatid cyst fluid antigen (SHCF) was somewhat reduced in the presence of normal human serum. The CAg detection assay would only be useful for assessment of hydatid infection status in patients with detectable CAg in serum samples.

Acids↗

Murine hybridoma-derived antibodies in the processing of antigens for the immunodiagnosis of hydatid (Echinococcus granulosus) infection in sheep.

Mice experimentally infected with hydatid parasite Echinococcus granulosus (secondary echinococcosis), were used as spleen cell donors for hybridoma production. Two hybridomas were produced which secreted antibody with anti-E. granulosus cyst fluid (EgCF) activity. Radioimmunoassays comparing the binding of these hybridoma-derived antibodies to E. granulosus versus several other antigen preparations from sheep parasites showed that the antibodies had a high degree of specificity for the hydatid parasite. However, using a panel of clinically defined sheep sera in a competitive radio-immunoassay, the binding of the hybridoma-derived antibodies to EgCF was inhibited strongly by sera from sheep infected with the common parasites Fasciola hepatica and Taenia hydatigena. When the hybridoma-derived antibodies were conjugated to CNBr-activated Sepharose and the crude EgCF applied to the affinity column, the "run through' antigen preparation showed a significant increase in specificity for experimental E. granulosus infection. A useful means of applying the hybridoma technology in the development of new immunodiagnostic reagents may be to select those murine hybridomas which produce high-affinity, cross-reacting antibodies and to use these antibodies in the processing of homologous antigen by affinity chromatography.

Animals↗

Spatial distribution patterns of Echinococcus multilocularis (Leuckart 1863) (Cestoda: Cyclophyllidea: Taeniidae) among red foxes in an endemic focus in Brandenburg, Germany.

Over a period of 40 months, 4374 foxes were randomly sampled from an area located in northwestern Brandenburg, Germany, and examined parasitologically for infections with Echinococcus multilocularis. Spatial analysis of the origin of infected animals identified two (one central and one southeastern) high-endemic foci with an estimated prevalence of 23.8%. By contrast, a prevalence of 4.9% was found in the remaining (low-endemic) area. The prevalences among juvenile and adult foxes were compared in the high-endemic and the low-endemic areas. To analyse the central high-endemic focus further, the random sample was stratified by zones representing concentric circles with a radius of 13 km (zone 1) or x(n-1) + 7 km for the remaining three zones from the apparent centre of this focus (anchor point). Prevalences calculated for each zone showed a decrease from zone 1 (18.8%) to zone 4 (2.4%) with significant differences for all zones but zones 3 and 4. The relative risk of an infection decreased rapidly in a distance range of 26 km around the high-endemic focus, whereas the relative risk remained unchanged within a distance of 5 km around the anchor point. The importance of heterogeneous spatial distribution patterns for the diagnosis and epidemiology of the infection is discussed.

Age Distribution↗

IL-5 expressed by CD4+ lymphocytes from Echinococcus multilocularis-infected patients.

IL-5 is a major factor inducing differentiation of B lymphocytes into immunoglobulin-producing cells as well as a main regulator of eosinophils. Recently, we have shown that peripheral blood mononuclear cells (PBMC) from patients with alveolar echinococcosis (AE) express IL-5 mRNA after stimulation with crude Echinococcus multilocularis (E.m.) antigen. To characterize the observed response in lymphocyte subpopulations, we cultured patients' PBMC in the presence of E.m. crude antigen for 18 h. PBMC were separated from seven patients by fluorescence-activated cell sorting (EPICSorter) into CD4+ and CD8+ subpopulations and from an additional seven patients by magnetic cell sorting (MACS) into CD4+, CD8+ and the CD4+/CD8+ depleted fractions. mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) for the cytokines IFN-gamma, IL-2, IL-3, IL-4, IL-5, IL-6, IL-10, as well as for beta-actin as control. IL-4 and IFN-gamma expression was positive in all of the patients in the stimulated CD4+ subgroup. IL-5 mRNA expression was detected in eight out of 14 CD4+ samples (58%) and not observed in the other subpopulations, or the unstimulated and healthy controls. Co-expression of other Th2 cytokines in the eight patients expressing IL-5 mRNA was found in five patients for IL-3 and in seven for IL-10. Expression of IL-5 and both Th2 cytokines (IL-3 and IL-10) was only observed in patients judged as critically ill. Out of the six patients who were regarded as cured after radical operation or as stabilized with or without chemotherapy, only two expressed IL-5. Out of those eight patients considered as critically ill, six expressed IL-5 mRNA and five of these co-expressed IL-3 and IL-10. Thus, we conclude that specific antigenic challenge of PBMC from patients with active or previous AE induces an IL-5 response of CD4+ lymphocytes. The expression of Th2-type interleukin mRNA is significantly more frequent in patients clinically judged as progressive. Furthermore, IgE was elevated only in patients regarded as critically ill (six out of eight). In none of the patients were eosinophils elevated. These data support a Th2-type immune response in patients with chronic E. multilocularis infection.

Actins↗

Secondary Echinococcus multilocularis infection in A/J mice: delayed metacestode development is associated with Th1 cytokine production.

The course of Echinococcus multilocularis infection was studied in four different strains of mice after intrahepatic inoculation of a metacestode homogenate. Among these strains of mice, A/J and BALB/c mice were characterized, respectively, as the most resistant and susceptible strains. Although there was no significant difference between the mean surface of hepatic metacestodes of these two strains of mice at any examination time, 13 weeks after infection, the mean metastatic burden of A/J mice was significantly lower than that of BALB/c mice. Moreover, at this time, some BALB/c mice spontaneously died from their infection whereas all A/J mice remained in good health. The relative resistance of A/J mice to parasite development was associated with a strong and sustained in vitro spleen cell proliferative response to a crude E. multilocularis extract as well as with a high parasite-induced production of IFN-gamma and IL-2. The susceptibility of BALB/c mice was on the contrary associated with a high IL-4 production. Interestingly, the parasite extract also stimulated a significant IL-4 production by spleen cells of uninfected susceptible BALB/c mice, but not by control A/J mouse spleen cells. Altogether, these results suggest that the relative resistance of A/J mice to E. multilocularis growth is associated with the development of T cell responses characterized by the production of high levels of Th1 cytokines.

Animals↗

Antibody response of Echinococcus granulosus infected mice: protoscolex specific response during infection is associated with decreasing specific IgG1/IgG3 ratio as well as decreasing avidity.

The antibody response was followed during 68 weeks in 17 Balb/c mice intraperitoneally (i.p.) infected with Echinococcus granulosus protoscoleces (PSC) and in three mice i.p. immunized with dead PSC. Titres of antibodies recognizing peptidic and glucidic PSC epitopes, as well as their isotypic and avidity profiles were followed by ELISA. In addition, antigen recognition patterns were analysed by immunoblot. The response against carbohydrate epitopes was dominant in infected and immunized mice but stronger in the first group. Infected mice showed similar profiles of specific IgG and IgM with maximum titres from week 38 to 53. Although IgG1 and IgG3 were the predominant antibody subclasses, the ratio of IgG1/IgG3 antibody titres as well as antibody avidity decreased during the experiment, encompassing a decrease in recognition of peptidic epitopes. Immunized mice did not show significant levels of specific IgM and, after week 15, showed IgG titres lower than the infected mice. IgG1 was the predominant IgG subclass during all the experiment with background levels of IgG3. The mean Ab avidity was high and showed no significant changes during immunization. Different patterns of response were thus produced by dead and developing live parasites. Although high avidity IgG1 antibodies were early found in both cases, lower avidity IgG3 antibodies were increasingly produced afterwards only in infected animals. The isotype switch and avidity decrease observed only during infection are consistent with a possible parasitic mechanism to evade host immunity.

Animals↗

Immunomodulation by hydatid cyst fluid toxin (Echinococcus granulosus).

Since the experimental infection by hydatid cysts (Echinococcus granulosus) in mice causes immunomodulation of the host, the effects of hydatid fluid (HF) and fractions of HF were compared in vitro and in vivo. Fractions of HF were obtained using ammonium sulphate precipitation, chloroform/methanol extraction and thin-layer chromatography (TLC). HF proved to be toxic to murine peritoneal macrophages in vitro, and when macrophages were incubated with the different fractions of HF, most toxicity was found in a single TLC-purified fraction with an adjuvant-like effect on the production of specific antibodies against bovine albumin and human red blood cells in mice. Treatment of mice with the toxin caused a drop in the percentage of peripheral blood lymphocytes. Flow-cytometric analysis showed that T-cells from toxin-treated mice had lower membrane-CD3, CD4 and CD8 density, and higher percentages of CD8+ splenocytes and CD4+ thymocytes expressing CD25. The toxin caused a down-regulation of CD4 and CD8 expression on thymocytes in vitro, that was dependent on the presence of macrophages. The results may attribute to these toxins a role in the host-parasite relationship of hydatidosis.

Animals↗

Intestinal and systemic humoral immunological events in the susceptible Balb/C mouse strain after oral administration of Echinococcus multilocularis eggs.

The aim of the study was to investigate the systemic and, for the first time, the intestinal humoral events in the susceptible Balb/C mouse strain after oral administration of Echinococcus multilocularis eggs. Thirty-one mice were divided into three groups; W-2, W-8 and control group. Each mouse of the W-2 and W-8 groups was orally infected with 1,500 E. multilocularis eggs, two weeks and eight weeks before sacrifice respectively. Control group mice received phosphate buffer saline. Measurement of anti-E. multilocularis and non-specific IgG, IgA and IgM, and of a transudation marker, albumin, were performed in serum and intestinal washings by a time-resolved immunofluorometric assay. These results were complemented by microscopic examination of the intestinal mucosa. This infection model is well-suited to the study of mucosal immunity during alveolar echinococcosis. It showed a major specific intestinal response in the early stage of the disease whereas the systemic response predominated later in the disease. Histopathological studies and calculation of the relative coefficient of excretion of Ig also confirmed that the presence of the parasite, even during a short period, was responsible for a local immunological and inflammatory response and for a change in mucosal permeability. Mucosal immunity could thus play a role in tolerance induction against E. multilocularis that could be a prerequisite for the subsequent development of the larvae in the liver, and for the occurrence of the parasitic disease, alveolar echinococcosis.

Animals↗

Growth kinetics of leukocyte cell lines cultured with hydatid fluid of Echinococcus granulosus equinus.

Oxidation of 3,(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and tritiated thymidine uptake were used to measure, respectively, the viable cell count and the S-phase activity of D10, B9, A20 and p388d leukocytic cell lines cultured in the presence of varying concentrations of fluid from fertile and infertile hydatid cysts of Echinococcus granulosus equinus. Exposure to hydatid fluid raised or lowered the entry of D10 cells into S-phase depending on the concentration of the fluid and of the supporting cytokines. Enlargement of the S-phase population was unaccompanied by increase in viable count indicating that the mitotic cycles induced by hydatid products were not completed. A similar conclusion was reached in respect of the p388d monocytic line, and both changes appear consistent with those occurring in histopathology in vivo. By contrast, the main effect on B9 and A20 B cells was inhibition of entry into S-phase.

Animals↗

Albendazole plus praziquantel versus albendazole alone as a pre-operative treatment in intra-abdominal hydatisosis caused by Echinococcus granulosus.

OBJECTIVE: To compare the effects of a combined medication of albendazole (10 mg/kg/day) plus praziquantel (25 mg/kg/day) to those of albendazole alone at different doses (10 and 20 mg/kg/day). METHOD: The protoscoleces' viability was studied in a consecutive series of patients affected by intra-abdominal hydatidosis caused by Echinococcus granulosus. In all cases the drugs were given during the month prior to surgery. RESULTS: A significant increase of patients with nonviable protoscoleces was observed in the group treated with the scolicides combination compared to those treated with albendazole alone, both at a dose of 10 mg/kg/day (P = 0.004) and at a dose of 20 mg/kg/day (P = 0.03). Albendazole sulphoxide levels in serum and in cyst fluid were higher in patients given the combined therapy than in those who received only albendazole (10 mg/kg/day: P = 0.016; 20 mg/kg/day: P = 0.034). Levels in the cysts were not significantly different probably due to the sample size; nevertheless a lineal relation between the values obtained in serum and inside the cysts could be discerned in the patients treated with the combined medication. CONCLUSION: Albendazole plus praziquantel is more effective than monotherapy with albendazole in the preoperative treatment of intra-abdominal hydatidosis.

Abdomen↗