Immunopathology of echinococcosis.
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Animals↗
Biomedical subjects
B Gottstein
Publications and source records attributed to B Gottstein.
[Frequency and cost of health problems in Swiss dairy cows and their calves (1993-1994)].
Between July 1993 and July 1994 morbidity and management information related to dairy cows and their calves up to the age of 8 weeks were recorded in 113 randomly selected dairy herds. Also recorded were any costs incurred through disease and prevention. Blood and faeces were analysed with respect to selected pathogens. The health problems most frequently diagnosed in cows were reproductive and udder diseases. Calves suffered most often from diarrhea, omphalitis and pneumonia. The directly disease-related costs per cow-year on average amounted to CHF 139.44 and CHF 4.18 per calf. For prevention, farmers spent on average CHF 10.18 per cow-year. Results from the laboratory analyses indicate that in 68.1% of the farms antibodies against Leptospira hardjo and in 61.9% against Coxiella burnetii were detected. In 8.0% of the farms antibodies against Mycobacterium paratuberculosis were found. Antibodies against BVD virus was present in 99.4% of the farms. Cows from 63.7% farms were infected with gastrointestinal strongylids. Veterinary assistance was required on average 1.96 times per cow-year. In almost all reproductive and puerperal disease cases a veterinarian was consulted while lameness in the majority of cases was treated by the owner. The veterinary profession was hardly ever involved in disease prevention.
Animals↗
[Frequency and etiology of calf losses and calf diseases in cow-calf farms. III. seroprevalence of selected diseases and prevalence of endoparasites and weaning age].
In a cross sectional study in 38 cow-calf farms blood and fecal samples were taken from 207 calves at an age of 8-10 months and their darms, in order to determine the seroprevalence of Leptospira hardjo, Coxiella burnetii, Toxoplasma gondii and the presence of the BVD-Antigen as well as the prevalence of endoparasites. The study was conducted in fall 1994 at the end of the grazing period. Eggs or larvaes of gastrointestinal helminths were detected in 74% of calves that were dewormed before the grazing period and in 88% of untreated calves. The difference between the two groups was statistically significant. In 83% of the weaned calves oocysts of Eimeria spp. were diagnosed. No significant difference in weight gain was observed between animals without endoparasites and animals infected with either helminths and/or Eimeria. In cows the prevalence was 61.5% for helminths and 45.7% for Eimeria spp. In calves the seroprevalence was 4% for Leptospira hardjo, 0.5% for Coxiella burnetii and 14.0% for Toxoplasma gondii. The seroprevalence in cows were 18% for Leptospira hardjo, 7.6% for Coxiella burnetii and 14.3% for Toxoplasma gondii. The prevalence of the BVD-Virus antigen was 0.5% for calves and cows.
Aging↗
A case of alveolar echinococcosis restricted to the pancreas.
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Acute Disease↗
[Infestation of water voles (Arvicola terrestris) with metacestodes of Echinococcus multilocularis in the canton Freiburg (Switzerland)].
The results of an investigation on Echinococcus multilocularis-metacestodes in European water voles (Arvicola terrestris) are shown. The investigation materials were 28 water voles captured in Schermann-traps on a meadow in the canton of Fribourg and subsequently maintained in laboratory cages. The animals were patho-anatomically and histo-pathologically examined, a part of them additionally with an E. multilocularis-specific direct immunofluorescence-assay and/or a polymerase-chain-reaction. Radiographs were obtained from one animal, showing typical calcifications as they often occur with alveolar echinococcosis. Altogether 11 out of 28 (39%) animals proved to be infected with E. multilocularis. As far as we know this represents the highest percentage of infested intermediate hosts ascertained in Europe. However, fertile, i.e. able to infect, protoscolices were detected in only two cases. In spite of this small number of protoscolices it can be shown that A. terrestris is able to maintain the lifecycle of this cestode at least spatially and temporally limited. In conclusion the possible measures for reducing the infection risk of the people in the affected community are shortly discussed.
Animals↗
Increased basal production of interleukin-10 by peripheral blood mononuclear cells in human alveolar echinococcosis.
The secretion of IL-10 by peripheral blood mononuclear cells (PBMC) and the expression of IL-10 mRNA in fractionated CD4+ and CD8+ lymphocyte subsets and non-B-non-T cells, with and without stimulation by the mitogen phytohemagglutinin-C (PHA-C) and specific Echinococcus multilocularis (E. multilocularis) antigens, were assessed in 7 patients with alveolar echinococcosis (AE) and 6 healthy subjects. Results of studies on IL-10 were compared to those on IFN-gamma, IL-4 and IL-5 in the same patients and control subjects. IL-10 production was significantly higher in patient PBMC-culture supernatants than in the control group supernatants, both at the basal level and after mitogen or specific E. multilocularis antigen stimulation. Both CD4+ and CD8+ lymphocyte populations and non-B-non-T cells of AE patients and controls expressed IL-10 mRNA. Semi-quantification of IL-10 mRNA revealed a significantly higher transcript level in unstimulated-CD8+ T cells from AE patients in comparison with CD8+ T cells of healthy donors. PBMC from patients produced very low levels of IL-4 but the production of IFN-gamma was not significantly depressed compared to the controls. PBMC, isolated from 4 AE patients and 4 control subjects stimulated with specific E. multilocularis antigens, secreted IL-5; IL-5 mRNA was only detected in the CD4+ lymphocyte subset. The secretion of IL-5 and the expression of IL-5 mRNA in healthy subjects could be due to the presence of non-specific mitogenic parasitic factors. This non-specific mitogenic activity of the parasite, besides inducing a high secretion of IL-10 in patients with evolutive AE, may contribute to the lack of host control of parasite growth and to the persistence of granulomatous lesions, due to the inhibition of an efficient Th1 immune response.
Adult↗
Discrimination of Neospora caninum from Toxoplasma gondii and other apicomplexan parasites by hybridization and PCR.
Neospora caninum is a protozoan parasite which causes neurological problems in dogs and abortion in cattle. As N. caninum is difficult to distinguish morphologically from Toxoplasma gondii, we developed a molecular tool capable of discriminating between the two parasites. Genomic DNA was isolated from in vitro cultured N. caninum tachyzoites and cloned into a plasmid vector. Resulting colonies were subsequently screened by differential hybridization using N. caninum and T. gondii DNA. Two clones were characterized in detail: one clone, termed pNc5, was found to be specific for N. caninum whereas the second clone, pNc1, hybridized with DNA from both parasites. The sequence of pNc5 was determined and different oligonucleotide primers were designed for use in the polymerase chain reaction (PCR). A 944 bp fragment was specifically amplified from N. caninum DNA, but not from DNA extracted from T. gondii or different Sarcocystis species. Positive signals in PCR were obtained with as little as 100 pg parasite template DNA. In addition, dual PCR with primer pairs specific for N. caninum and T. gondii allowed the detection of either parasite in mixed samples.
Animals↗
Electron microscopical investigation of surface alterations on Giardia lamblia trophozoites after exposure to a cytotoxic monoclonal antibody.
The present study describes a transmission electron microscopical investigation of trophozoites from Giardia lamblia clone GS/M-83-H7 after exposure to monoclonal antibody (MAb) G10/4. From previous studies it is known that this antibody immunoreacts with the parasite's major surface antigen VSP (variable surface protein) and exhibits a complement-independent cytotoxic effect on trophozoites of clone GS/M-83-H7. Our investigations revealed that cytotoxicity of MAb G10/4 is associated with shedding of VSP-containing membrane vesicles from the parasite surface and a concomitant partial disruption of the cellular membrane. These morphological alterations depend on the cross-linking capacity of the antibody because the immunoreactivity of respective monovalent F(ab)' has no significant influence on the cell-surface structure. These findings indicate that the membrane-disintegrative activity of MAb G10/4 may be responsible for the parasitocidal function of the antibody.
Animals↗
Identification of a major surface protein on Neospora caninum tachyzoites.
Neospora caninum is a recently identified coccidian parasite that is closely related to Toxoplasma gondii. Molecules associated with the surface of N. caninum tachyzoites are likely to be involved in the process of adhesion and invasion of host cells. They probably also participate in the interaction of the parasite with the immune system, and they could play an important role in the pathogenesis of the parasite. To identify such surface molecules, we performed subcellular fractionation studies of isolated N. caninum tachyzoites. Employing the nonionic detergent Triton-X-114, we prepared a membrane fraction. Immunoblot analysis of this fraction using polyclonal antisera directed against tachyzoites of N. caninum and T. gondii resulted in the identification of a protein of approximately 43 kDa (Nc-p43). This molecule was present in two isolates of Neospora (Nc-1 and Liverpool) but was absent in Toxoplasma (RH-strain) tachyzoites. Further immunofluorescence and immunogold transmission electron microscopy (TEM) studies using affinity-purified anti-Nc-p43 antibodies demonstrated the presence of this molecule on the surface of N. caninum tachyzoites.
Animals↗
Adhesion and invasion of bovine endothelial cells by Neospora caninum.
Neospora caninum is a recently identified coccidian parasite which was, until 1988, misdiagnosed as Toxoplasma gondii. It causes paralysis and death in dogs and neonatal mortality and abortion in cattle, sheep, goats and horses. The life-cycle of Neospora has not yet been elucidated. The only two stages identified so far are tissue cysts and intracellularly dividing tachyzoites. Very little is known about the biology of this species. We have set up a fluorescence-based adhesion/invasion assay in order to investigate the interaction of N. caninum tachyzoites with bovine aorta endothelial (BAE) cells in vitro. Treatment of both host cells and parasites with metabolic inhibitors determined the metabolic requirements for adhesion and invasion. Chemical and enzymatic modifications of parasite and endothelial cell surfaces were used in order to obtain information on the nature of cell surface components responsible for the interaction between parasite and host. Electron microscopical investigations defined the ultrastructural characteristics of the adhesion and invasion process, and provided information on the intracellular development of the parasites.
Animals↗
Serological analysis of antigenic heterogeneity of Giardia lamblia variant surface proteins.
Neonatal ZU.ICR mice were infected with trophozoites of Giardia lamblia clone GS/M-83-H7 expressing the variant surface protein (VSP) H7 and were subsequently investigated for their serum antibody response directed against VSPH7. Recombinant polypeptides, representing overlapping segments of VSPH7, and native Giardia proteins were used as antigenic reagents to examine the antigenic substructure of VSPH7 and the extent of antigenic variation in vivo. VSPH7 proved to be the predominant antigen of the parasite with respect to serum antibody reactivity. The data indicated that VSPH7 basically consists of two antigenically distinct parts: (i) a unique, variant-specific 314-amino-acid N-terminal region which elicits a low antibody response preferentially detectable during the early phase of the infection and (ii) a 171-amino-acid C-terminal region which elicits a high antibody response during the later phase or after resolution of the infection. The epitopes of the C-terminal region appear to be shared by other, as yet uncharacterized, variant antigens. The highly conserved 34-amino-acid stretch at the extreme C terminus of VSPH7 exhibited no immunoreactivity to any of the sera tested. Further investigations indicated that antigenic variation of the intestinal parasite population was associated with a diversification into at least six to nine new antigen types. These variant antigens were extremely heterogeneous in size ranging from approximately 50 to 115 kDa. None of these proteins shared antigenic epitopes with the 314-amino-acid N-terminal portion, but several of them cross-reacted with antibodies specific to the 171-amino-acid C-terminal portion of the VSP from the original inoculum.
Animals↗
Diagnosis of Neospora caninum and Toxoplasma gondii infection by PCR and DNA hybridization immunoassay.
A recently described PCR test for the identification of Neospora caninum and Toxoplasma gondii has been further developed and optimized in view of its practicability for routine diagnostic application. The N. caninum-specific PCR was adapted to the diagnostic operating standard of the T. gondii-specific PCR in that the uracil DNA glycosidase system was introduced, which eliminates potential carry-over contaminations of amplified target DNA from previous reactions. Furthermore, both PCR tests were optimized by including a DNA hybridization immunoassay based on the use of the commercially available Gen-eti-k DEIA kit. This assay allowed highly sensitive and specific detection of respective DNA amplification products and thus substantially facilitated the reading and interpretation of the test results.
Animals↗
Use of a 96-well format for the affinity purification of maltose-binding protein (MBP) fusion proteins.
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ATP-Binding Cassette Transporters↗
Neospora caninum: specific oligonucleotide primers for the detection of brain "cyst" DNA of experimentally infected nude mice by the polymerase chain reaction (PCR).
Both tachyzoites and bradyzoites in tissue cysts of Neospora caninum are morphologically difficult to distinguish from those of other cyst-forming apicomplexan parasites such as Toxoplasma gondii. Thus, molecular tools may contribute to easy identification of the parasite. Based upon an N. caninum-specific DNA fragment that we have recently cloned, 5 sense (Np1, Np3, Np5, Np7, Np21) and 4 antisense (Np2, Np4, Np6, Np8) oligonucleotides were designed for a sensitive and specific polymerase chain reaction (PCR). Among 19 combinations of sense and antisense primers, the Np21/Np6, Np21/Np4, and Np7/Np6 primer pairs were found to generate specific single bands in the presence of at least 10 pg genomic parasite DNA as a template. The primer pair Np21/Np6 was able to detect a single tachyzoite in the background of DNA derived from 2 mg of brain tissue. In experimentally infected athymic ICR:nu/nu mice, N. caninum-DNA was detected consistently from brain tissue at days 13 and 18 after subcutaneous inoculation of tachyzoites. The presence or absence of the organisms in the cerebrum in either proliferative or cystic form was examined by immunohistological staining. The results indicate that PCR with the primer pair Np21/Np6 could provide an efficient tool for large-scale epidemiological studies using brain tissue obtained at necropsy.
Animals↗
Investigations on a Swiss area highly endemic for Echinococcus multilocularis.
Anecdotal information suggested that a focus of hyperendemicity may be present in a small area of the Canton of Fribourg in Switzerland. Therefore, the prevalence of E. multilocularis was assessed both in the fox and the rodent population over a two-season-period. A high prevalence ranging between 47% and 56% was consistently determined in the fox population. An Arvicola terrestris population was infected at 39% in the first season of investigation and at 11% in the following season. A subsequent seroepidemiological survey in the population of inhabitants surrounding the area provided no indication of seroconversion and thus no indication of infection for humans. However, a longer-term survey will be needed to assess more precisely the risk of disease occurrence among these inhabitants.
Animals↗
["Arbitrarily primed PCR". Or: chance in the service of science].
"Arbitrarily primed PCR" (AP-PCR) methods are based on the amplification of DNA with arbitrarily selected primers. In the present review article two selected applications of this methodical approach are summarized. Using the RAPD ("Random Amplified Polymorphic DNA") technique the genetic variability of different organisms can be analyzed by generating a genomic fingerprint. Echinococcus granulosus isolates (metacestodes) from Spain and Switzerland were comparatively characterized by the use of this molecular epidemiological tool. The following groups of genetically related isolates could be identified: (a) equine isolates (horse/donkey) from Spain and Switzerland, (b) cattle isolates from Switzerland, (c) goat isolates from Spain and pig isolates from both countries, (d) sheep, cattle and human isolates from Spain. Isolates derived from Swiss patients were forming a separate group with respect to their genetic relatedness. As a further application of the AP-PCR, the development of a novel technique for the construction of cDNA libraries from minute amounts of starting material using an Echinococcus multilocularis metacestode library as an example is presented.
Animals↗
[Diagnostic PCR in veterinary parasitology: tritrichomonosis, neosporosis/toxoplasmosis echinococcosis/cysticercosis].
The PCR is now widely introduced as a diagnostic and epidemiological tool in veterinary and human parasitology. Certain parasitic infections are detected using PCR with much higher sensitivity compared to conventional methods, and novel molecular approaches are considered for the analysis of infectiological questions. A broad spectrum of parasites relevant for veterinary and human parasitology already can be diagnosed by PCR. In the present review article, PCR-based methods developped or applied at the Institute of Parasitology in Berne for the detection of protozoan infections (Tritrichomonosis, Neosporosis, Toxoplasmosis) and helminthic infections (Echinococcosis, Taeniosis) are summarized.
Animals↗
Immunological parameters associated with susceptibility or resistance to alveolar hydatid disease in Yupiks/Inupiats.
Alveolar hydatid disease (AHD) is a serious and often fatal disease with a relatively high prevalence among the Alaska native Yupik/Inupiat population. In a few patients, however, a spontaneous cure of the disease has been shown by demonstrating the presence of dead metacestode lesions. The present study shows a comparative analysis of the humoral (antibody activity to two different antigens: Em2-antigen and recombinant II/3-10-antigen) immune response and a respective immunogenetic background (HLA-DR typing) in (i) "susceptible" patients who had a still active intrahepatic metacestode and (ii) "resistant" patients who were shown to be spontaneously cured by presenting dead and calcified lesions. Control groups included relatives who were genetically closely related and less related cohabitants of the same villages. Antibody levels in the Em2- and the II/3-10-ELISA were high for patients who had still active lesions and low (Em2-ELISA) or negative (II/3-10-ELISA) for cured patients with dead lesions. Comparative HLA-DR analyses between infected and non-infected Yupiks/Inupiats revealed a slight tendency for susceptibility markers respective to the HLA-DRB1*0901 and HLA-DRB1*1601,02 genes.
Alaska↗