Parasites are an important and diverse group of microbial pathogens that have a great impact on human and animal health, especially in tropical and subtropical areas of the world. Parasites are the most complex pathogens, as they are eukaryotic organisms with large genomes. These large genomes enabled the development of complex life cycles comprising distinct developmental stages that are either free-living or can infect one or most hosts. Plasmodium parasites are probably the most well-known parasites, as these cause malaria, a disease that lists among the top three infectious diseases with the highest number of fatal cases per year (ca. 450.000). However, most parasitic diseases do not cause fatal diseases, as it would also result in death of the parasite itself and thus limit its possibilities to produce offspring. For this reason, and because most parasitic diseases are mainly prevalent in poor and rural areas of the world, many parasitic infections were neglected diseases. Today, however, these Neglected Tropical Diseases (NTD) are considered to be important as their prevalence can be extremely high in rural areas and because they cause substantial morbidity. Hence, the World Health Organisation (WHO) has started special programs to combat and eradicate these parasitic diseases.
In high income European countries, such as the Netherlands, parasitic infections not only occur as imported diseases in immigrants and travellers from tropical countries, but they occur also in immune compromised patients and various opportunistic parasitic infections can cause severe problems in these patients. After incorporation of the tropical disease unit of the Havenziekenhuis into the Erasmus MC, the Erasmus MC is now for the above mentioned complex patient groups a national expertise centre. For this reason parasitic infections are an important discipline within the department of Medical Microbiology & Infectious Diseases of the Erasmus MC. Research objects are the development of state of the art diagnostic methods and fundamental research that aims to improve diagnostics as well as the treatment of parasitic infections.
Within the Netherlands, the national expertise centre for parasitology of the Erasmus MC has a broad expertise on clinical parasitology in combination with translational parasitological research from bench to bedside. In contrast to other Dutch universities, research on parasitic infections is not focused on developing countries in tropical areas, but it is focussed on the detection and treatment of parasitic infections in travellers and immigrants. Clinical presentation and disease progression are often substantially different in naïve adults with acute disease compared to chronically infected people in endemic countries. In addition, even larger differences exist in diagnostic tools and options for supporting (intensive) care and treatment. For instance, malaria is a much more fulminant disease in naïve adults compared to children and adults in endemic countries. However, knowledge on optimal treatment of malaria is almost exclusively derived from studies in endemic countries. Hence, information on the pathogenesis in naïve adults and on optimal supportive care that is available in high income countries, is limited. Similarly, development of diagnostic tools for low income countries has other requirements (low cost) than for high income countries (excellent performance). Therefore, the translational research on parasitic infections in the Erasmus MC is focussed on host-parasite interactions in order to (1) obtain fundamental knowledge on parasites and disease pathogenesis in naïve hosts that can be applied to improve treatment of patients, and (2) to improve diagnostic methods to detect parasitic infections, not only in tropical low income countries, but also in non-endemic high income countries, such as the Netherlands.
Over the last decade the national expertise centre for parasitology of the Erasmus MC has gathered a large biobank of clinical materials and has set up a comprehensive clinical database for imported parasitic diseases that can be life threatening (e.g. malaria and leishmaniasis). This biobank and clinical database are used to develop or evaluate novel diagnostic methods (e.g. molecular and serological detection methods, identification of markers for disease severity). In addition to this clinical research, more fundamental aspects of the interaction of the parasite with the host haemostasis are studied, as this aspect is important in malaria, visceral leishmaniasis and schistosomiasis. These studies recently resulted in a patent for the use of a parasitic enzyme to treat thrombotic disorders. Finally, parasites often have special adaptations that are essential to survive in their host. Some of these adaptations proofed to be valid targets to treat diseases and recently this resulted in the identification of several repurposing drugs, as the identified drugs were not only powerful drugs to treat amoebic meningitis, a very rare but highly fatal infection (>95% mortality), but these drugs are currently already in clinical use for treatment of non-infectious diseases.
Next to these research lines, the national expertise centre for parasitology of the Erasmus MC is frequently requested to participate in (or execute entire) studies on parasitic infections (e.g. Controlled Human Malaria Infection studies to evaluate vaccine efficacy). It is for its broad clinical expertise that other centres request the Erasmus MC to participate. Hence, many collaborations exist both at the national and international level.
Field(s) of expertise
- Clinical parasitology (diagnosis and treatment of parasitic infections)
- Host parasite interactions
- External quality assessment schemes (EQAS)
- Schistosomiasis, malaria and free-living amoeba
Education and career
Parasitology is an important and visual subject to teach. Medical students not only need to be aware of the common parasitic infections endemic in the Netherlands, such as giardiasis, cryptosporidiosis and ectoparasites (fleas, ticks and lice), but they also need to have knowledge on the life threatening parasitic diseases that can be imported from tropical areas, such as malaria, leishmaniasis and sleeping sickness, which is crucial for early detection of these diseases by general practitioners and clinicians in local hospitals. For infectious disease specialists (‘artsen-microbioloog’ and ‘internist-infectiologen’), much more comprehensive knowledge in clinical parasitology is required. For them state of the art courses have been developed, which include e-learning tutorials and blended learning modules. These courses are also open for infectious disease residents from other universities, as many of those either do not have substantial expertise in clinical parasitology or a very limited number of clinical patients with parasitic infections. Furthermore, the national expertise centre for parasitology of the Erasmus MC organises various practical courses for external technicians on methods to diagnose parasitic infections (e.g. malaria) and it coordinates the (inter)national external quality assessment schemes for parasitology (in conjunction with the Dutch Foundation for Quality Assessment in Medical Laboratories (SKML)).
Next to training of the medical doctors of the future, it is important that young biomedical researchers are trained in research on parasitic infections to ensure that also in the future this field has sufficient research potential. The scientific research performed on clinical relevant subjects in the broad field of clinical parasitology is unique in the Netherlands.