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Betschart, Bruno

Nom
Betschart, Bruno
Affiliation principale
Fonction
Professeur.e émérite
Email
bruno.betschart@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/302
_
0000-0001-6057-9374

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  • Publication
    Métadonnées seulement
    A study on the seasonal epidemiology of Anoplocephala spp.-infection in horses and the appropriate treatment using a praziquantel gel (Droncit (R) 9% oral gel)
    (2006)
    Roelfstra, Lise-Lore
    ;
    Betschart, Bruno 
    ;
    Pfister, Kurt 
    In a study on the seasonal dynamics of the gastro-intestinal nematode egg production in horses, one breeding farm also revealed a particularly high prevalence of Anoplocephola spp. infection. Consequently, this farm was chosen for analysing the seasonal pattern of the tapeworm egg excretion over a one year period in order to establish the most favourable periods for an appropriate and successful cestocidal treatment. The seasonal analysis showed a significantly higher (p < 0,05) Anoplocephala spp. egg excretion between July and October, i.e. during the second part of the grazing period. This result clearly underlines the importance of a cestocidal treatment during that period of the year Subsequently, horses of this farm and of a second farm with a high prevalence of Anoplocephola spp. were used to evaluate the efficacy of praziquantel in a specific oral gel formulation for horses under field conditions. The efficacy of praziquantel was tested in a total of 33 horses from the two farms harbouring a coproscopically detected Anoplocephala spp. infection prior to treatment. Praziquantel (Droncit (R) 9%, oral gel, 1mg/kg bodyweight) was administered to the horses according to their body weight. The efficacy of the drug was evaluated ten days after treatment by a double faecal ana lysis. Thereby, no Anoplocepholo spp. eggs were found. in the faeces of 32 horses (97%). The single horse remaining positive for Anoplocephola spp. eggs did not completely swallow the anthelmintic gel and consequently, did not receive the appropriate dose of the drug.
  • Publication
    Métadonnées seulement
  • Publication
    Métadonnées seulement
    Prophylaxis failure due to probable mefloquine resistant P-falciparum from Tanzania
    (2003)
    Wichmann, O
    ;
    Betschart, Bruno 
    ;
    Loscher, T
    ;
    Nothdurft, H D
    ;
    Sonnenburg, F V
    ;
    Jelinek, T
    Failures of mefloquine prophylaxis in travellers returning from Africa have been reported repeatedly. Noncompliance to chemoprophylaxis is considered to be a major factor for failure. Only few reports on mefloquine prophylaxis failure in sub-Saharan Africa were able to report blood levels of the drug that were sufficient for prophylactic effectiveness. We report the case of a 44-year-old German female who travelled to Tanzania for 3 weeks. The patient reported that she never missed a dose of mefloquine during her weekly prophylaxis schedule. Four weeks after returning from Tanzania, the patient presented with fever, headache and myalgia. Only a few trophozoites of Plasmodium falciparum were found in a thick film. Blood levels of mefloquine at that stage were at 1400 ng/ml, thus largely excluding non-compliance and malabsorption. To our knowledge, this is the first case of confirmed prophylaxis failure due to mefloquine resistance in East Africa. (C) 2003 Elsevier Science B.V. All rights reserved.
  • Publication
    Métadonnées seulement
    Seasonal epidemiology of ticks and aspects of cowdriosis in N'Dama village cattle in the Central Guinea savannah of Cote d'Ivoire
    (2002)
    Knopf, L
    ;
    Komoin-Oka, C
    ;
    Betschart, Bruno 
    ;
    Jongejan, Frans
    ;
    Gottstein, Bruno
    ;
    Zinsstag, Jacob
    In the Central Guinea savannah of Cote d'Ivoire, cattle breeding started only similar to30 years ago. The impact of parasitism on the overall health status and productivity of the trypanotolerant N'Dama cattle in this area is unknown. In close collaboration with national veterinary institutions and local farmers, we studied spectrum, burden and seasonal dynamics of ticks (including aspects of cow-driosis) on N'Dama village cattle. In a longitudinal study, three randomly selected cattle herds (traditional farming type) of one village were examined repeatedly for ticks. Spectrum, burden, seasonal epidemiology of ticks were assessed. In these traditional herds (which lack (ecto)parasite management), all animals were infested by ticks at monthly counts. Five different tick species were identified; the four genera in order of frequency were: Amblyomma (overall prevalence 96%), Boophilus (47%), Hyalomina (
  • Publication
    Métadonnées seulement
    Isoniazid plus sulphadoxine-pyrimethamine can reduce morbidity of HIV-positive patients treated for tuberculosis in Africa: A controlled clinical trial
    (1999)
    Haller, Louis
    ;
    Sossouhounto, Raoul
    ;
    Coulibaly, Issa M
    ;
    Dosso, Mireille
    ;
    Kone, Moussa
    ;
    Adom, Hilaire
    ;
    Meyer, Urs A
    ;
    Betschart, Bruno 
    ;
    Wenk, Markus
    ;
    Haefeli, Walter E
    ;
    Lobognon, Legré R
    ;
    Porquet, Michel
    ;
    Kabore, Geneviève
    ;
    Sorenson, Fred
    ;
    Reber-Liske, Rosemaria
    ;
    Sturchler, Dieter
    An annual 20% excess mortality rate is observed in HIV-seropositive patients after treatment for tuberculosis. An affordable secondary prophylaxis against main opportunistic diseases is needed, i.e. against tuberculosis, toxoplasmosis, pneumocystosis and other infections occurring in this target population. This open prospective randomized study assessed morbidity and mortality in 2 cohorts of HIV-seropositive patients having recently recovered from pulmonary tuberculosis: 134 patients assigned to prophylactic treatment with isoniazid (INH, 300 mg once daily) plus sulphadoxine-pyrimethamine (S, 500 mg/P, 25 mg once weekly), and 129 were controls, comparable for sex, age, weight and HIV-serology. Patients were followed-up for up to 2 years: 192 person-years (PY) in the prophylaxis group and 142 PY in the control group. Four patients developed tuberculosis and 20 patients died in the prophylaxis group, compared to 10 and 23 controls, respectively. Sick days were reported by 22 patients in the prophylaxis group and by 77 patients in the control group. This prophylaxis was associated with a moderate decrease of mortality (log rank test: p = 0.1736), a significant decrease of tuberculosis incidence (log rank test: p = 0.0234), a highly significant reduction of adverse events and sick days, and a prevention of wasting (p = 0.008) and anaemia (p = 0.045). No death from toxoplasmosis occurred in the prophylaxis group as compared to 2 possible cases among controls; toxoplasmosis IgG levels declined in treated patients, but increased in controls (p = 0.01). There was no adverse drug reaction due to SP (10,006 doses) or to INH. Compliance with SP intake was good, but moderate as with INH intake. We conclude that a secondary prophylaxis with INH+SP represents a cost-effective measure to improve health conditions of HIV-infected adults in Cote d'Ivoire, following a full treatment course against tuberculosis. Copyright (C) 1999 S. Karger AG, Basel.
  • Publication
    Métadonnées seulement
    DNA extraction from Ascaris suum muscle tissue
    (1998)
    Di Mito, Carmela
    ;
    Betschart, Bruno 
    A new method for the extraction of DNA from Ascaris suum muscle has been developed. It combines a standard SDS-based extraction with a plant DNA extraction procedure. The use of SDS and proteinase It allows the elimination of proteins, while CTAB and polyclar AT eliminate glycogen and polyphenols. The DNA thus obtained can easily be digested by endonucleases and amplified by PCR.
  • Publication
    Métadonnées seulement
    Repetitive peptide motifs in the cuticlin of Ascaris suum
    (1996)
    Bisoffi, Marco
    ;
    Marti, Stefan
    ;
    Betschart, Bruno 
    The cuticle of parasitic nematodes is composed of extracellular structural proteins. Over 90% of these proteins are collagenous molecules in the basal and median layers of the cuticle. The outermost layers of the cuticle, the epicuticle, is composed of non-collagenous proteins, that represent the structural surface of nematodes. In Ascaris these proteins have been termed 'cuticlins'. While cuticular collagens have been well studied by both biochemical and genetic means, knowledge of the molecular structure of cuticlin components of parasitic nematodes is scarce. In the present paper we report on the production of monoclonal antibody 8.1, which is specific for cuticlin: but does nor recognize collagen epitopes. We have screened a cDNA library derived from adult Ascaris suum mRNA of the hypodermal tissue underlying and synthesizing the cuticle. One positive cDNA clone encodes alanine-rich repetitive motifs, which are part of the insoluble cuticlin of the outermost layers of the epicuticle of Ascaris suum. This was shown in immunocytochemical experiments using specific polyclonal antisera raised against these motifs, expressed as fusion protein with glutathione S-transferase of the helminth Schistosoma japonicum. Comparison of the repetitive amino acid sequence with structural proteins of the nematode Caenorhabditis elegans and the insects Locusta migratoria and Ceratitis capitata revealed a minimal consensus motif.
  • Publication
    Métadonnées seulement
    Trypanosoma-Brucei-Brucei and High-density-lipoproteins - old and new thoughts on the identity and mechanism of the trypanocidal factor in human serum
    (1995)
    Lorenz, Patrick
    ;
    Betschart, Bruno 
    ;
    Owen, James S
    Nature has Provided humans with a surprising means of protection against the African trypanosome, Trypanosoma brucei brucei. There is consensus, in that this singular trypanocidal factor is serum high-density lipoproteins (HDL), which the trypanosomes engulf through a physiological, receptor-mediated pathway for delivery to acidic intracellular vesicles. There is also controversy, however, in that the active particles and their essential cytotoxic elements are disputed, in part reflecting the ill-defined mechanism by which the parasites are finally killed. Here Patrick Lorenz, Bruno Betschart and jim Owen discuss the possibilities for resolving these discrepancies and speculate on the prospects of exploiting this unexpected Property of human HDL for Protecting livestock.
  • Publication
    Métadonnées seulement
    Heterogeneity in the properties of the trypanolytic factor in normal human serum
    (1994)
    Lorenz, Patrick
    ;
    James, Richard W
    ;
    Owen, James S
    ;
    Betschart, Bruno 
    Although it seems clear that the trypanolytic factor in human serum capable of killing Trypanosoma brucei brucei is high density lipoprotein (HDL), it nevertheless remains controversial as to whether the trypanolytic properties of HDL are confined to a specific subclass or whether all particles have activity. In the present study, we have compared the lytic activities of serum fractions from six normal individuals prepared by gradient ultracentrifugation and also, to avoid ultracentrifugally-induced loss of HDL apolipoproteins, by gel filtration using fast protein liquid chromatography (FPLC). All sera displayed trypanolytic activity in fractions corresponding to the general density (rho = 1.06-1.20 g ml(-1)) and size (59-440 kDa) limits conventionally used to describe bulk human HDL, the particles between rho = 1.18-1.20 g ml(-1) and between 214-440 kDa being particularly lytic. But some sera additionally contained fractions with powerful activity outside these density (rho > 1.24 g ml(-1)) and size (> 1000 kDa) ranges. Nevertheless, such fractions were considered to contain material with HDL characteristics; apolipoprotein A-I, the major protein of HDL, was always present and the lytic activity of the sera could be completely neutralized by absorption with HDL antiserum. We conclude that all of the trypanolytic activity in human sera is associated with HDL particles and that it is a property of several HDL subpopulations with very different density and size characteristics. Presumably the well-recognized wide variation in trypanocidal activity of normal human sera reflects differences in the quantities of these HDL subpopulations rather than in the total amount of a single, uniquely lytic particle.