176 research outputs found

    Comparison of Intranasal Outer Membrane Vesicles with Cholera Toxin and Injected MF59C.1 as Adjuvants for Malaria Transmission Blocking Antigens AnAPN1 and Pfs48/45

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    Purified protein vaccines often require adjuvants for efficient stimulation of immune responses. There is no licensed mucosal adjuvant on the market to adequately boost the immune response to purified antigens for intranasal applications in humans. Bacterial outer membrane vesicles (OMV) are attractive candidates potentially combining antigenic and adjuvant properties in one substance. To more precisely characterize the potential of Escherichia coli OMV for intranasal vaccination with heterologous antigens, immune responses for AnAPN1 and Pfs48/45 as well as ovalbumin as a reference antigen were assessed in mice. The intranasal adjuvant cholera toxin (CT) and parenteral adjuvant MF59C.1 were used in comparison. Vaccinations were administered intranasally or subcutaneously. Antibodies (total IgG and IgM as well as subclasses IgG1, IgG2a, IgG2b, and IgG3) were measured by ELISA. T cell responses (cytotoxic T cells, Th1, Th17, and regulatory T cells) were determined by flow cytometry. When OMV were used as adjuvant for intranasal immunization, antibody and cellular responses against all three antigens could be induced, comparable to cholera toxin and MF59C.1. Antigen-specific IgG titres above 1 : 10 5 could be detected in all groups. This study provides the rationale for further development of OMV as a vaccination strategy in malaria and other diseases

    Comparison of Intranasal Outer Membrane Vesicles with Cholera Toxin and Injected MF59C.1 as Adjuvants for Malaria Transmission Blocking Antigens AnAPN1 and Pfs48/45

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    Purified protein vaccines often require adjuvants for efficient stimulation of immune responses. There is no licensed mucosal adjuvant on the market to adequately boost the immune response to purified antigens for intranasal applications in humans. Bacterial outer membrane vesicles (OMV) are attractive candidates potentially combining antigenic and adjuvant properties in one substance. To more precisely characterize the potential of Escherichia coli OMV for intranasal vaccination with heterologous antigens, immune responses for AnAPN1 and Pfs48/45 as well as ovalbumin as a reference antigen were assessed in mice. The intranasal adjuvant cholera toxin (CT) and parenteral adjuvant MF59C.1 were used in comparison. Vaccinations were administered intranasally or subcutaneously. Antibodies (total IgG and IgM as well as subclasses IgG1, IgG2a, IgG2b, and IgG3) were measured by ELISA. T cell responses (cytotoxic T cells, Th1, Th17, and regulatory T cells) were determined by flow cytometry. When OMV were used as adjuvant for intranasal immunization, antibody and cellular responses against all three antigens could be induced, comparable to cholera toxin and MF59C.1. Antigen-specific IgG titres above 1 : 10 5 could be detected in all groups. This study provides the rationale for further development of OMV as a vaccination strategy in malaria and other diseases

    Molecular markers of anti-malarial drug resistance in southwest Ethiopia over time: regional surveillance from 2006 to 2013

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    Background Drug resistance is one of the main reasons of anti-malarial treatment failures and impedes malaria containment strategies. As single nucleotide polymorphisms (SNPs) have been found to correlate with anti-malarial drug resistance, the surveillance strategy includes continuous monitoring of known molecular markers and detection of new mutation patterns. With the introduction of artemisinin-based combination therapy, selection of specific patterns has been observed worldwide. Methods From March to June 2013, whole blood was collected on filter paper from microscopically malaria positive patients in Jimma zone (District), southwestern Ethiopia. Plasmodium falciparum, Plasmodium vivax and mixed infections were included. SNPs were investigated by conventional or real-time PCR, restriction fragment length pattern analysis or sequencing. Results were compared to molecular patterns from Ethiopian isolates in 2004, 2006 and 2008/9. Results Plasmodium falciparum, P. vivax, and mixed infections were molecularly confirmed in 177, 80, and 14 samples, respectively. In P. falciparum, mutations in the pfcrt, pfmdr 1and pfATP 6 (SERCA) gene were investigated. Whereas the mutation in the pfcrt gene at codon 76 K was still found in 95.6 % of all samples, the pfmdr 1 86 T mutation fell to 1.2 % (2/163) in 2013 compared to 9 % in 2008/9 and 86 % in 2006 (P <0.001). The pfmdr 1 184 F mutation dominated with 100.0 % (172/172) in 2013. Sequencing of the recently reported PF3D7_1343700 kelch propeller domain showed no mutation at codon 476. First sequencing data of the pvmdr 1 gene from Jimma region revealed a prevalence of the mutations 976 F and 1076 L in 72.7 % (16/23) and 100.0 % (19/19) of the isolates, respectively. Conclusion Since the introduction of artemether-lumefantrine (AL) in Jimma, Ethiopia, in 2006, the prevalence of certain SNPs associated with AL use has increased. Markers for chloroquine resistance in P. vivax were highly frequent. Continuous molecular and clinical surveillance are of paramount importance

    Candidatus Borrelia kalaharica Detected from a Febrile Traveller Returning to Germany from Vacation in Southern Africa

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    A 26 year-old female patient presented to the Tropical Medicine outpatient unit of the Ludwig Maximilians-University in Munich with febrile illness after returning from Southern Africa, where she contracted a bite by a large mite-like arthropod, most likely a soft-tick. Spirochetes were detected in Giemsa stained blood smears and treatment was started with doxycycline for suspected tick-borne relapsing fever. The patient eventually recovered after developing a slight Jarisch-Herxheimer reaction during therapy. PCR reactions performed from EDTA-blood revealed a 16S rRNA sequence with 99.4% similarity to both, Borrelia duttonii, and B. parkeri. Further sequences obtained from the flagellin gene (flaB) demonstrated genetic distances of 0.066 and 0.097 to B. parkeri and B. duttonii, respectively. Fragments of the uvrA gene revealed genetic distance of 0.086 to B. hermsii in genetic analysis and only distant relations with classic Old World relapsing fever species. This revealed the presence of a novel species of tick-borne relapsing fever spirochetes that we propose to name "Candidatus Borrelia kalaharica", as it was contracted from an arthropod bite in the Kalahari Desert belonging to both, Botswana and Namibia, a region where to our knowledge no relapsing fever has been described so far. Interestingly, the novel species shows more homology to New World relapsing fever Borrelia such as B. parkeri or B. hermsii than to known Old World species such as B. duttonii or B. crocidurae

    Different mutation patterns of Plasmodium falciparum among patients in Jimma University Hospital, Ethiopia

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    <p>Abstract</p> <p>Background</p> <p>The emergence of drug resistance is a major problem in malaria control. Combination of molecular genotyping and characterization of mutations or single nucleotide polymorphisms (SNPs) correlated with drug resistance can provide information for subsequent surveillance of existing and developing drug resistance patterns. The introduction of artemether/lumefantrine (AL) as first-line treatment, never used before in Ethiopia, allowed the collection of baseline data of molecular polymorphisms before a selection due to AL could occur.</p> <p>Method</p> <p>97 patients with uncomplicated falciparum malaria were recruited from April to June 2006 and treated with either AL, quinine (Q) or atovaquone/proguanil (AP) in Jimma University Hospital, Ethiopia. Mutations or SNPs associated with resistance to these drugs were analysed by RFLP (<it>pfdhfr</it>, <it>pfmdr1</it>) and sequencing of the target genes (<it>pfcytb</it>, <it>pfserca </it>).</p> <p>Results</p> <p>SNPs previously reported to be associated with resistance to the study drugs were identified in recrudescent and treatment sensitive isolates. A total of seven recrudescences were obtained. The <it>pfmdr1 </it>N86Y mutation was found in 84.5% of isolates. The triple mutation 51I,59R,108N of the <it>pfdhfr </it>gene occured in high frequency (83.3%) but no <it>pfcytb </it>mutation was detected. Sequencing showed a variety of previously described and new mutations in the <it>pfserca </it>gene.</p> <p>Conclusion</p> <p>The prevalence of mutations was in accordance with the expected patterns considering recent drug regimens. The broad introduction of AL and the cessation of former drug regimens might probably change the current distribution of polymorphisms, possibly leading to decreased sensitivity to AL in future. Continuous surveillance of molecular patterns in this region is, therefore, recommended.</p

    High Seroprevalence for Typhus Group rickettsiae, southwestern Tanzania.

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    Rickettsioses caused by typhus group rickettsiae have been reported in various African regions. We conducted a cross-sectional survey of 1,227 participants from 9 different sites in the Mbeya region, Tanzania; overall seroprevalence of typhus group rickettsiae was 9.3%. Risk factors identified in multivariable analysis included low vegetation density and highway proximity

    Cross-sectional, descriptive study of Chagas disease among citizens of Bolivian origin living in Munich, Germany

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    PURPOSE: Chagas disease (CD) has become a global health issue mainly due to migration. Germany lacks surveillance data and is home to a large Latin American immigrant population. Recognising that Bolivia is the country with the highest CD prevalence in Latin America, this cross-sectional, descriptive pilot study investigated CD and associated factors among citizens of Bolivian origin living in Munich, Germany. METHODS: Participants completed a questionnaire in order to collect socioeconomic and health-related data. In addition, serology was performed. In case of positive serological tests, PCR diagnostic and clinical staging together with disease management was initiated. Qualitative research was conducted to identify personal and community barriers as well as strategies to increase CD awareness among the population at risk. RESULTS: Between June 2013 and June 2014, 43 people from Bolivia (or descendants) were enrolled. A total of 9.3% (4/43), of whom two women were of childbearing age, tested seropositive (ELISA and IFAT), and one also by PCR. For 2/4 positive participants, clinical evaluation was performed and the indeterminate form of CD was diagnosed. Knowledge about CD symptoms and ways of transmission were completely absent among 55.8% (24/43, 2/4 with CD) and 30.2% (13/43, 1/4 with CD) of participants, respectively. A total of 27.9% (12/43, 0/4 with CD) of participants had donated blood prior to the study, whereas 62.8% (27/43, 3/4 with CD) were motivated to donate blood in the future. The qualitative research identified lack of knowledge as well as stigma and fears related to CD. CONCLUSIONS: Despite the small number of participants, the prevalence of CD as well as the potential risk of non-vectorial transmission was alarming. Campaigns adapted for Latin American migrants as well as control strategies should be developed and put in place in order to prevent non-vectorial transmission and actively detect cases of CD in Germany.This study was supported through the Clinical Leave Programme (TI 07.001, grant to MP) and the MD Programme (TI 07.003, grant to MP and MH) by the German Center for Infection Research (DZIF). The University of Munich (LMU) contributed through the programme ‘Lehre@LMU’ (grants to MP and CS), and Mundo Sano provided financial and human resources to plan the informational approach to reach the Bolivian community living in Munich and to design and perform the qualitative research.S

    Severe Plasmodium knowlesi infection with multi-organ failure imported to Germany from Thailand/Myanmar

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    During the last two decades human infections with Plasmodium knowlesi are increasingly diagnosed in South East Asia and have also been reported in travellers. A severe case of imported P. knowlesi infection in a 73-year old German is presented, who had been travelling through Myanmar and Thailand for three weeks. Microscopy showed a parasitaemia of 3% and different parasite stages including band-forms resembling Plasmodium malariae. Due to the clinical picture of severe malaria and the microscopical aspect (combination of parasites resembling P. malariae and Plasmodium falciparum), P. knowlesi was suspected. The patient was treated with intravenous quinine; he was put on mechanical ventilation and catecholamines due to cardiorespiratory failure. Parasitaemia was cleared rapidly but renal function deteriorated resulting in intermittent haemodialysis. The patient was hospitalized for six weeks but he recovered completely without any physical sequelae. Plasmodium knowlesi mono-infection was confirmed by molecular methods later on. Plasmodium knowlesi infection has to be taken into account in feverish travellers returning from Thailand/Myanmar. Moreover this species can cause life-threatening or even lethal complications. Accordingly severe P. knowlesi infection should be treated like severe P. falciparum infections

    Neue Ergebnisse ĂŒber das JungquartĂ€r im NeckarschwemmfĂ€cher bei Heidelberg

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    Am Beispiel eines reprĂ€sentativen Aufschlusses nordwestlich Mannheim-Wallstadt wird aufgezeigt, wie sich mit Hilfe palĂ€ontologischer Methoden (Konchylien, 14C-Daten, Pollen- und Holzartenbestimmung) sowie Sediment- und Strukturmerkmalen (KorngrĂ¶ĂŸe, Schichtung, Kryoturbationserscheinungen etc.) das JungquartĂ€r des NeckarschwemmfĂ€chers stratigraphisch, palĂ€oklimatisch und genetisch gliedern lĂ€ĂŸt. Das Riß-WĂŒrm-Interglazial, bisher im nördlichen Oberrheingraben nur sedimentologisch erfaßt, kann im NeckarschwemmfĂ€cher auf Grund von Eichenholzfunden und warmzeitlichen Konchylien — in wesentlich geringerer Tiefe als bisher angenommen — nachgewiesen werden. Mittels Holzartenbestimmung lĂ€ĂŸt sich von etwa 50 000 bis ca. 42 500 J.v.h. ein kĂŒhl-atlantisches und von ca. 42 500 bis etwa 27 000 J.v.h. ein kĂŒhl-kontinentales Klima rekonstruieren. FĂŒr ein sehr kaltes Klima von 43 000—39 000 J.v.h., wie es in den Niederlanden von Zagwijn und Paepe (1968) festgestellt wurde, ergeben sich keine Anhaltspunkte. Das WĂŒrm-Hochglazial (oberes Pleniglazial) ist entweder nur relativ geringmĂ€chtig oder nur indirekt (durch intensive Kryoturbationserscheinungen etc.) nachweisbar.researc
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