De Geest B.G.,Ghent University |
Willart M.A.,Ghent University |
Lambrecht B.N.,Ghent University |
Pollard C.,Ghent University |
And 5 more authors.
Angewandte Chemie - International Edition | Year: 2012
Immunizing: To evoke highly potent immune responses against recombinant antigens, hollow capsules consisting of layers of dextran sulphate and poly-L-arginine that encapsulate the antigen ovalbumin (orange circles) were coated with immune-activating CpG-containing oligonucleotides (green). These capsules were readily internalized by dendritic cells (see picture) and showed activity in further immunization experiments. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Vanaerschot M.,Antwerp Institute of Tropical Medicine
Critical reviews in microbiology | Year: 2013
Drug-resistant microorganisms (DRMs) are generally thought to suffer from a fitness cost associated with their drug-resistant trait, inflicting them a disadvantage when the drug pressure reduces. However, Leishmania resistant to pentavalent antimonies shows traits of a higher fitness compared to its sensitive counterparts. This is likely due the combination of an intracellular pathogen and a drug that targets the parasite's general defense mechanisms while at the same time stimulating the host's immune system, resulting in a DRM that is better adapted to withstand the host's immune response. This review aims to highlight how this fitter DRM has emerged and how it might affect the control of leishmaniasis. However, this unprecedented example of fitter antimony-resistant Leishmania donovani is also of significance for the control of other microorganisms, warranting more caution when applying or designing drugs that attack their general defense mechanisms or interact with the host's immune system.
De Vooght L.,Antwerp Institute of Tropical Medicine |
Caljon G.,Antwerp Institute of Tropical Medicine |
Van Hees J.,Antwerp Institute of Tropical Medicine |
Van Den Abbeele J.,Antwerp Institute of Tropical Medicine
Molecular biology and evolution | Year: 2015
Sodalis glossinidius, a maternally inherited secondary symbiont of the tsetse fly, is a bacterium in the early/intermediate state of the transition toward symbiosis, representing an important model for investigating establishment and evolution of insect-bacteria symbiosis. The absence of phylogenetic congruence in tsetse-Sodalis coevolution and the existence of Sodalis genotypic diversity in field flies are suggestive for a horizontal transmission route. However, to date no natural mechanism for the horizontal transfer of this symbiont has been identified. Using novel methodologies for the stable fluorescent-labeling and introduction of modified Sodalis in tsetse flies, we unambiguously show that male-borne Sodalis is 1) horizontally transferred to females during mating and 2) subsequently vertically transmitted to the progeny, that is, paternal transmission. This mixed mode of transmission has major consequences regarding Sodalis' genome evolution as it can lead to coinfections creating opportunities for lateral gene transfer which in turn could affect the interaction with the tsetse host. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
Vanham G.,Antwerp Institute of Tropical Medicine |
Vanham G.,University of Antwerp |
Van Gulck E.,Antwerp Institute of Tropical Medicine |
Van Gulck E.,Present Address Community Of Research Excellence And Advanced Technology Create
Retrovirology | Year: 2012
Immunotherapy aims to assist the natural immune system in achieving control over viral infection. Various immunotherapy formats have been evaluated in either therapy-naive or therapy-experienced HIV-infected patients over the last 20 years. These formats included non-antigen specific strategies such as cytokines that stimulate immunity or suppress the viral replication, as well as antibodies that block negative regulatory pathways. A number of HIV-specific therapeutic vaccinations have also been proposed, using in vivo injection of inactivated virus, plasmid DNA encoding HIV antigens, or recombinant viral vectors containing HIV genes. A specific format of therapeutic vaccines consists of ex vivo loading of autologous dendritic cells with one of the above mentioned antigenic formats or mRNA encoding HIV antigens.This review provides an extensive overview of the background and rationale of these different therapeutic attempts and discusses the results of trials in the SIV macaque model and in patients. To date success has been limited, which could be explained by insufficient quality or strength of the induced immune responses, incomplete coverage of HIV variability and/or inappropriate immune activation, with ensuing increased susceptibility of target cells.Future attempts at therapeutic vaccination should ideally be performed under the protection of highly active antiretroviral drugs in patients with a recovered immune system. Risks for immune escape should be limited by a better coverage of the HIV variability, using either conserved or mosaic sequences. Appropriate molecular adjuvants should be included to enhance the quality and strength of the responses, without inducing inappropriate immune activation. Finally, to achieve a long-lasting effect on viral control (i.e. a " functional cure" ) it is likely that these immune interventions should be combined with anti-latency drugs and/or gene therapy. © 2012 Vanham and Van Gulck; licensee BioMed Central Ltd.
Lejon V.,Antwerp Institute of Tropical Medicine |
Bentivoglio M.,University of Verona |
Franco J.R.,World Health Organization
Handbook of Clinical Neurology | Year: 2013
Human African trypanosomiasis or sleeping sickness is a neglected tropical disease that affects populations in sub-Saharan Africa. The disease is caused by infection with the gambiense and rhodesiense subspecies of the extracellular parasite Trypanosoma brucei, and is transmitted to humans by bites of infected tsetse flies. The disease evolves in two stages, the hemolymphatic and meningoencephalitic stages, the latter being defined by central nervous system infection after trypanosomal traversal of the blood-brain barrier. African trypanosomiasis, which leads to severe neuroinflammation, is fatal without treatment, but the available drugs are toxic and complicated to administer. The choice of medication is determined by the infecting parasite subspecies and disease stage. Clinical features include a constellation of nonspecific symptoms and signs with evolving neurological and psychiatric alterations and characteristic sleep-wake disturbances. Because of the clinical profile variability and insidiously progressive central nervous system involvement, disease staging is currently based on cerebrospinal fluid examination, which is usually performed after the finding of trypanosomes in blood or other body fluids. No vaccine being available, control of human African trypanosomiasis relies on diagnosis and treatment of infected patients, assisted by vector control. Better diagnostic tools and safer, easy to use drugs are needed to facilitate elimination of the disease. © 2013 Elsevier B.V.
Agyepong I.A.,University Utrecht |
Orem J.N.,Health systems and services cluster |
Hercot D.,Antwerp Institute of Tropical Medicine
Tropical Medicine and International Health | Year: 2011
This brief paper addresses some of the difficulties inherent in international ideological approaches to solving the complex problems of health care financing and delivery in poor countries using Ghana as an example. It concludes with an appeal for problem solving approaches involving informed debate as to optimal ways forward to solve low income country health financing woes that are open minded about possible options rather than vested in particular positions. © 2010 Blackwell Publishing Ltd.
Clerinx J.,Antwerp Institute of Tropical Medicine |
Van Gompel A.,Antwerp Institute of Tropical Medicine
Travel Medicine and Infectious Disease | Year: 2011
Schistosomiasis is a tropical parasitic disease caused by blood-dwelling fluke worms of the genus Schistosoma whose infective stages, the cercariae, are amplified through mollusks acting as intermediate hosts. People are infected when exposed to fresh water containing cercariae that penetrate the skin. There are however considerable differences in intensity of infection and morbidity, depending on the pattern of exposure and the infective species. In travellers, schistosomiasis differs substantially from infection in endemic populations in many aspects: geography, morbidity, treatment and prevention. In migrants, schistosomiasis manifests itself in a way more akin to what is seen in endemic populations. In this paper we will review the specific issues associated with schistosomiasis in travellers and migrants, with emphasis on the acute disease manifestations in non-immune persons, and on neuroschistosomiasis as a potential severe complication. We discuss new trends in diagnosis and treatment with respect to the specific disease stage, and summarize precautionary measures and novel ways to prevent Schistosoma infection in travellers. © 2010 Elsevier Ltd. All rights reserved.
Deborggraeve S.,Antwerp Institute of Tropical Medicine |
Buscher P.,Antwerp Institute of Tropical Medicine
Expert Review of Molecular Diagnostics | Year: 2012
This article will review the most recent progress in the molecular diagnosis of sleeping sickness and its potential role in patient management and disease control. While PCR remains restricted to research and reference laboratories, promising alternative molecular platforms have emerged over the last few years. Several loop-mediated isothermal amplification assays have been developed for detection and identification of the parasite with reported high analytical sensitivity and specificity. Simplified loop-mediated isothermal amplification formats have been designed and are undergoing evaluation studies in the field. Accurate diagnosis based on specific detection of the parasite's ribosomal RNA has been made possible by the isothermal nucleic acid sequence-based amplification and by direct hybridization with fluorescent detection probes. In addition to the technological progress, the authors also discuss the diagnostic performance of molecular tests in the most recent clinical evaluation studies and briefly present some viewpoints for the near future. © 2012 Expert Reviews Ltd.
Marchal B.,Antwerp Institute of Tropical Medicine |
Dedzo M.,PO Box HP 72 |
Kegels G.,Antwerp Institute of Tropical Medicine
BMC Health Services Research | Year: 2010
Background. Realist evaluation offers an interesting approach to evaluation of interventions in complex settings, but has been little applied in health care. We report on a realist case study of a well performing hospital in Ghana and show how such a realist evaluation design can help to overcome the limited external validity of a traditional case study. Methods. We developed a realist evaluation framework for hypothesis formulation, data collection, data analysis and synthesis of the findings. Focusing on the role of human resource management in hospital performance, we formulated our hypothesis around the high commitment management concept. Mixed methods were used in data collection, including individual and group interviews, observations and document reviews. Results. We found that the human resource management approach (the actual intervention) included induction of new staff, training and personal development, good communication and information sharing, and decentralised decision-making. We identified 3 additional practices: ensuring optimal physical working conditions, access to top managers and managers' involvement on the work floor. Teamwork, recognition and trust emerged as key elements of the organisational climate. Interviewees reported high levels of organisational commitment. The analysis unearthed perceived organisational support and reciprocity as underlying mechanisms that link the management practices with commitment. Methodologically, we found that realist evaluation can be fruitfully used to develop detailed case studies that analyse how management interventions work and in which conditions. Analysing the links between intervention, mechanism and outcome increases the explaining power, while identification of essential context elements improves the usefulness of the findings for decision-makers in other settings (external validity). We also identified a number of practical difficulties and priorities for further methodological development. Conclusion. This case suggests that a well-balanced HRM bundle can stimulate organisational commitment of health workers. Such practices can be implemented even with narrow decision spaces. Realist evaluation provides an appropriate approach to increase the usefulness of case studies to managers and policymakers. © 2010 Marchal et al; licensee BioMed Central Ltd.
News Article | November 8, 2016
November 14 is World Diabetes Day. Globally about 442 million people live with this chronic condition, most of them in low-income countries, where health systems often function poorly. As they are not equipped to follow-up on patients or improve the quality of care, chronic disease management largely falls under the responsibility of the patients. In her doctoral thesis, Dr Josefien van Olmen of the Antwerp Institute of Tropical Medicine (ITM) says that much-touted mobile technologies for self-management alone will not solve the problem. Dr van Olmen and colleagues studied how health care systems in low-income countries can improve care for people with chronic diseases and support the self-management of patients, through the use of new features such as mobile technologies. They investigated how diabetes care programmes have developed in three countries: the Democratic Republic of Congo, Cambodia and the Philippines. The researchers also looked at the effects of a new mobile health (mHealth) intervention in all three countries. This multi-country study involved almost 1500 diabetes patients, who were followed-up multiple times during the course of two years. The patients received text messages several times a week that highlighted the importance of healthy eating habits, doing more physical exercise or wearing shoes to avoid foot ulcers, a common effect of long-term diabetes. "These people make day-to-day decisions about behaviours that potentially influence the course of their illness," said Josefien van Olmen, "so it is essential that they are well-informed. Our intervention was designed to change their lifestyle, their behaviour, which was an ambitious goal." "Our study was different from other mHealth studies in terms of its the duration, the variation of patient characteristics and the scope of the intervention. We also faced many unforeseen difficulties along the way, ranging from technical issues such as filled inboxes or lost phones to challenges at programme level." The researchers found that the intervention via text messages did not lead to more people with controlled diabetes after two years, showing that more is needed to improve the fate of diabetes patients in low-income countries. At the end of the study, 34% of the patients receiving SMS had well-controlled levels of blood glucose, which was, statistically, not more than the patients who received routine care. "However, there were some improvements for all patients in the study which illustrate the influence of the overall programme in which the patient participated. For instance, their knowledge and attitude of their own illness showed considerable improvement. In addition, there were improvements in the pharmacological management of hypertension and diabetes, with an increase of more than 10% of people receiving medication for hypertension, added van Olmen. "Mobile health is not a game changer in itself. Its integration into the overall programme and the quality of the overall programme are far more crucial." The lessons learnt are relevant for other chronic diseases as well. According to van Olmen's study, tackling chronic diseases in low-income countries requires interventions focusing on health care providers, patients and their families alike. Van Olmen carried out the research in the framework of the TEXT4DSM study, which was sponsored by the International Diabetes Foundation (IDF). It was a joint effort of ITM and the Free University of Amsterdam. She will defend her PhD thesis in Amsterdam on Tuesday 29 November.