J A R van den Hoek

Gezond Amsterdam, Amsterdamo, North Holland, Netherlands

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Publications (25)40.25 Total impact

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    ABSTRACT: A study was undertaken to estimate the seroprevalence of parvovirus B19 infection in the general adult population of Amsterdam, The Netherlands. To our knowledge this is the first study testing parvovirus B19 in a random sample of the Dutch adult population. The study was a cross-sectional survey, and the study sample was stratified by age and ethnicity, with deliberate oversampling of minority ethnic groups. Serum samples obtained from 1,323 residents in 2004 were tested for antibodies to parvovirus B19. Basic demographic data (gender, age, country of birth, and number of children) were also available. Sixty-two percent of the participants were seropositive; corrected for the oversampling the estimated prevalence in the Amsterdam adult population was 61%. No specific predictors or risk groups for seropositivity were identified. In our urban adult study population no positive correlation with increasing neither age, nor significant differences between age groups were found. These results imply that almost 40% of the adult Amsterdam population is susceptible to infection. J. Med. Virol. 81:1305-1309, 2009. (c) 2009 Wiley-Liss, Inc.
    Journal of Medical Virology 08/2009; 81(7):1305-9. · 2.37 Impact Factor
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    ABSTRACT: To gain insight into hepatitis B virus (HBV) transmission in the Netherlands. Descriptive. During 2004, epidemiological data and blood samples (if available) were collected for all reported cases of acute HBV infections in the Netherlands. Following DNA isolation and amplification a 648 base pairs fragment of the HBV S gene was sequenced and subjected to phylogenetic analysis. The sequencing details were also linked to epidemiological information. In 2004, 291 cases ofacute HBV infections were reported. Blood samples were received from 171 patients (59%), and the genotype could be determined for 158 patients (54%). 6 genotypes were identified: A (64%), B (3%), C (3%), D (21%), E (5%) and F (4%). Of all patients with genotype A, 52% had been infected via homosexual or bisexual contact and 16% via heterosexual contact. Of all patients with genotype D, 42% had been infected via heterosexual contact and 15% via homosexual or bisexual contact. The genotype A cluster was extremely homogeneous with many identical sequences, while genotype B-E clusters were more heterogeneous. 4 identical sequences were found within genotype F, but the patients could not be epidemiologically linked. Sexual transmission, particularly via homosexual or bisexual contact in men, formed the most important risk factor for acquiring an acute HBV infection. Genotype A was predominant in the Netherlands, especially among homosexual or bisexual men. Most infections within genotype D occurred as a result of heterosexual contact. The results show that there was ongoing transmission of HBV in homosexual or bisexual men, while in heterosexuals more cases of new introduction were seen, possibly via chronic carriers from areas where HBV is endemic.
    Nederlands tijdschrift voor geneeskunde 01/2009; 152(49):2673-80.
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    ABSTRACT: This paper provides an estimation of the lifetime health-care cost of HIV-infected children and an update of the cost-effectiveness of universal HIV-screening of pregnant women in Amsterdam (The Netherlands). During 2003-2005, we collected data concerning the prevalence of newly diagnosed HIV-infected pregnant women in Amsterdam. Also, data on resource utilization and HAART regimen for HIV-infected children was gathered from a national registry. Using Kaplan-Meier survival analysis, we estimated the life-expectancy of a vertically HIV-infected child at 19 years, with the corresponding lifetime health-care costs of 179,974 Euros. HIV-screening of pregnant women could prevent 2.4 HIV transmissions annually in Amsterdam, based on an estimated prevalence of nine yet undiagnosed HIV-positive pregnant women per 10,000 pregnancies. We show that universal HIV screening during pregnancy generates significant net cost savings and health benefits in most situations. Universal antenatal HIV screening is justified in Amsterdam from a health-economic point of view.
    International Journal of STD & AIDS 11/2008; 19(10):668-75. · 1.00 Impact Factor
  • Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 02/2008; 13(2). · 5.49 Impact Factor
  • G J B Sonder, J A R van den Hoek
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    ABSTRACT: Zusammenfassung Hepatitis-B- und -C-Viren rufen chronische Infektionen mit einer ausgeprägten Virämie hervor, die häufig unerkannt bleiben. Daher trägt das medizinische Personal bei der Ausübung verletzungsträchtiger Eingriffe ein erhöhtes Risiko, mit HBV oder HCV infiziert zu werden bzw. diese Viren auf Patienten zu übertragen. Das Ausmaß der Virämie schwankt individuell beträchtlich, und auch das Übertragungsrisiko variiert in Abhängigkeit vom medizinischen Eingriff/der medizinischen Tätigkeit. Hochvirämische HBV-Träger mit HBeAg übertragen das Virus bei risikobehafteten Eingriffen im Mittel zu 4% auf die von ihnen operierten Patienten, HBeAg-negative Chirurgen mit einer Virämie zwischen 10 6 und 10 7 HBV-DNA-Moleküle/ml zu 1,5%.Wegen des Fehlens von gesicherten Übertragungen bei einer Virämie unter 10 5 HBV-DNA-Moleküle/ml lässt sich ein Restrisiko von unter 1:100.000 ableiten, dass ein operativ tätiger Arzt mit niedriger Viruslast in 15 Jahren auch nur einen Patienten infiziert. 8 bekannt gewordene HCV-Träger unter Chirurgen haben zu 0,15% (17/11.119) das Virus auf ihre Patienten übertragen,wobei ihre Viruslast (soweit bekannt) immer um oder über 10 6 HCV-RNA-Moleküle/ml lag. Gegenwärtige Hinweise und Empfehlungen von zuständigen Fachgesellschaften und Institutionen sehen eine Impfung des Personals gegen HBV mit Erfolgskontrollen, Einstellungsuntersuchungen auf HBV und HCV und weiteren regelmäßigen Untersuchungen auf HCV sowie bei fehlender Immunität auch auf HBV vor. Infiziertes Personal mit Virämie muss entweder von sich aus auf die Ausübung verletzungsträchtiger operativer Tätigkeiten verzichten oder aber die Zulässigkeit bestimmter Tätigkeiten unter Berücksichtigung des individuellen Infektionsstatus von einer Expertenkommission prüfen lassen.
    Nederlands tijdschrift voor geneeskunde 01/2008; 151(50):2809; author reply 2809-10.
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    ABSTRACT: To investigate the epidemiological links between several outbreaks of hepatitis A in The Netherlands (2001-2004). Descriptive. Blood samples taken in connection with reports of hepatitis A to municipal health centres from 2001-2004, were typed by determining the nucleotide sequence of the VP3-VP1 and the VP1-P2A regions of the genome of the hepatitis A virus (HAV). Genetic distances were represented graphically by means of a phylogenetic tree. The study into the spread of various subtypes of HAV showed a clear link between the HAV-(sub)genotype and risk of transmission: in men that have sex with men only genotype 1A occurred, in travellers to African countries genotype 1B was predominantly seen. A database containing various viral strains from people with hepatitis A in The Netherlands could, if kept up to date, be used as an aid in confirming the classical way of tracing sources as well as for the evaluation of preventative measures.
    Nederlands tijdschrift voor geneeskunde 01/2008; 151(50):2779-86.
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    ABSTRACT: In order to enhance screening and preventive strategies, this study investigated the seroprevalence of hepatitis A, B, and C in the general adult urban population and in subgroups. In 2004, sera from 1,364 adult residents of Amsterdam were tested for viral markers. Sociodemographic characteristics were collected using a standardized questionnaire. For hepatitis A, 57.0% was immune. Of first-generation immigrants from Turkey and Morocco, 100% was immune. Of all Western persons and second-generation non-Western immigrants, approximately half was still susceptible. For hepatitis B, 9.9% had antibodies to hepatitis B core antigen (anti-HBc) and 0.4% had hepatitis B surface antigen. Anti-HBc seroprevalences were highest among first-generation immigrants from Surinam, Morocco, and Turkey, and correlated with age at the time of immigration, and among men with a sexual preference for men. Seroprevalence among second-generation immigrants was comparable to Western persons. The seroprevalence of hepatitis C virus antibodies was 0.6%. In conclusion, a country with overall low endemicity for viral hepatitis can show higher endemicity in urban regions, indicating the need for differentiated regional studies and prevention strategies. More prevention efforts in cities like Amsterdam are warranted, particularly for hepatitis A and B among second-generation immigrants, for hepatitis B among men with a sexual preference for men, and for hepatitis C. Active case finding strategies are needed for both hepatitis B and C.
    Journal of Medical Virology 01/2008; 79(12):1802-10. · 2.37 Impact Factor
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    ABSTRACT: To gain insight into hepatitis B virus (HBV) transmission in the Netherlands, epidemiological data and sera were collected from reported cases of acute HBV infections in the Netherlands in 2004. Cases were classified according to mode of transmission. A fragment of the S-gene of HBV (648 bp) was amplified, sequenced, and subjected to phylogenetic analysis. Of the 291 acute HBV cases reported in 2004, 158 (54%) were available for genotyping. Phylogenetic analysis identified 6 genotypes: A (64%), B (3%), C (3%), D (21%), E (5%) and F (5%). Of HBV infected men having sex with men, 86% were infected with genotype A, accounting for 43% of all patients infected with this genotype. There were only three reported cases of injecting drug use of which one was available for sequencing (genotype A). Unlike the genotype A cluster, sequences within the genotype B-E clusters were heterogenic. Within genotype F, several isolates had identical sequences, but patients could not be epidemiologically linked. Sexual transmission, particularly by men having sex with men was the most important transmission route for HBV. Injecting drug use plays a minor role. Genotype A is predominant in the Netherlands, especially among men having sex with men. In addition to imported strains, there seems to be a pool of related but non-identical strains circulating among chronic carriers in the migrant population, from which occasionally new patients are infected, primarily by heterosexual transmission.
    Journal of Medical Virology 08/2007; 79(7):895-901. · 2.37 Impact Factor
  • J A R van den Hoek, E P F IJzerman, R A Coutinho
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    ABSTRACT: During the period 6-28 July 2006, 30 confirmed cases of Legionella infection were identified in Amsterdam, 2 of which were fatal. All had a positive urinary antigen test, by which Legionella pneumophila serogroup I could be demonstrated. Consultations between the parties involved in the control of infectious diseases started on July 7th, as soon as it became clear that there was an outbreak. On July 10th it was established that relatively many of these patients lived in the eastern part of the city centre. After a study of the prevailing winds during the past 3 weeks, the search for installations containing water was started. A cooling tower in the town centre was closed on July 11th by way of precaution. During the following week, this tower was proven to be the source of the outbreak.
    Nederlands tijdschrift voor geneeskunde 09/2006; 150(33):1808-11.
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    ABSTRACT: To evaluate the impact and effectiveness of risk-group vaccination against hepatitis A targeted at migrant children living in a country with low endemicity of hepatitis A. Retrospective population based data analysis. Routinely collected data on hepatitis A incidence in migrant children and other risk groups in Amsterdam from 1 January 1992 to 2004 were analyzed and related to exposure, immunity and vaccination coverage in migrant children. The overall hepatitis A incidence in Amsterdam declined after a pediatric vaccine was introduced in 1997. This decline was seen in migrant children traveling to hepatitis A-endemic countries, contacts with hepatitis A patients, primary school students, injecting drug users, and persons with unknown source of infection, but not in men who have sex with men (MSM) or in travelers to endemic countries other than migrant children. The hepatitis A vaccination campaigns are effective: they reduce both import and secondary HAV cases. The campaigns could be more efficient and cost-effective if the hepatitis B vaccinations currently given to these groups were replaced by a combined hepatitis A and B vaccine. This would increase the hepatitis A vaccination coverage considerably and further reduce the hepatitis A incidence.
    Vaccine 07/2006; 24(23):4962-8. · 3.49 Impact Factor
  • A G Koek, L P M J Bovée, J A R van den Hoek, A J Bos, S M Bruisten
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    ABSTRACT: In Amsterdam, 17 of the 55 gastroenteritis (GI) outbreaks reported from January 2002 to May 2003 were confirmed to be caused by noroviruses (NV). In this study, we describe the molecular epidemiology of a group of nine outbreaks associated with a catering firm and two outbreaks, 5 months apart, in an Amsterdam hospital. All outbreaks were typed to confirm their linkage, and the hospital-related cases were studied to see if the two outbreaks were caused by one persisting NV strain or by a reintroduction after 5 months. For the outbreaks associated with the catering firm one NV genogroup I strain was found which was identical in sequence among customers and employees of the caterer. This was not the strain that predominantly circulated in 2002/2003 in and around Amsterdam, which was the NV genogroup II4 "new variant" (GgII4nv) strain. In the Amsterdam hospital, the two outbreaks were caused by this predominant GgII4nv type, and we argue that NV was most likely reintroduced in the second outbreak from the Amsterdam community.
    Journal of Clinical Virology 03/2006; 35(2):167-72. · 3.29 Impact Factor
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    J Worp, A Boonstra, R A Coutinho, J A R van den Hoek
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    ABSTRACT: Tattooing, body piercing and permanent makeup are increasing in popularity. Here, we describe the procedures involved in these practices, their risks, the content of guidelines developed by the Municipal Health Service in Amsterdam (the Netherlands) to reduce infection risks, the legislation in the city of Amsterdam, and results of monitoring in tattoo and piercing studios.
    Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 02/2006; 11(1):34-6. · 5.49 Impact Factor
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    J A R van den Hoek, E P F IJzerman, Roel A Coutinho
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    ABSTRACT: During the period 6-28 July 2006, 30 confirmed cases of Legionella infection were identified in Amsterdam, 2 of which were fatal. All had a positive urinary antigen test, by which Legionella pneumophila serogroup I could be demonstrated. Consultations between the parties involved in the control of infectious diseases started on July 7th, as soon as it became clear that there was an outbreak. On July 10th it was established that relatively many of these patients lived in the eastern part of the city centre. After a study of the prevailing winds during the past 3 weeks, the search for installations containing water was started. A cooling tower in the town centre was closed on July 11th by way of precaution. During the following week, this tower was proven to be the source of the outbreak.
    01/2006;
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    ABSTRACT: Previous studies on the molecular epidemiology of hepatitis A virus (HAV) in Amsterdam, The Netherlands, show that subgenotype 1A is mainly seen among homosexual men practising anonymous oral-anal sex in saunas and darkrooms, while subgenotype 1B is usually detected among children originating from Morocco, and subgenotype 3A is mostly found among travellers to Pakistan. We studied the genotype distribution in a more rural area of The Netherlands, Noord-Brabant, and compared it with Amsterdam. We collected blood and feces samples from 34 HAV IgM(+) individuals who were reported from August 2001-March 2003 at the Municipal Health Service (MHS) Heart for Brabant (Brabant). We also collected feces samples from nine household contacts of whom the HAV IgM status was not known. HAV RNA was isolated and subsequently amplified by reverse transcriptase polymerase chain reaction (RT-PCR) at the VP1-P2a and the VP3-VP1 region, sequenced and analysed. In most cases, relations between risk groups and HAV subgenotypes in Noord-Brabant were similar to those in Amsterdam. Next to genotypes 1 and 3 we also detected a genotype 2/7 strain in a Noord-Brabant case. Also, in contrast to the Amsterdam study, sporadic transmission occurred among various risk groups. Children involved in a school-related outbreak were infected with strains identical to one that was previously isolated from a man who has sex with men (MSM). Also, Dutch patients having no epidemiological link with Turkish or Moroccan children harboured strains imported from high-endemic countries. Furthermore, we report a special case in which HAV may be causally involved in meningitis. The results of this study show that the molecular epidemiology of HAV in The Netherlands can be more complicated than previously anticipated and that HAV phylogenetic studies can provide important information for the design of appropriate public health measures.
    Journal of Clinical Virology 03/2005; 32(2):128-36. · 3.29 Impact Factor
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    ABSTRACT: In 2003 the Municipal Health Service in Amsterdam started to screen pregnant women for HIV according to the opting-out method. In this method the HIV test is routinely included in the prenatal screening along with hepatitis B virus (HBV) and syphilis. If the woman does not want to be tested for HIV then she must actively opt out of this test. This screening method was chosen because in the universal screening method used in 2002, women had to give their explicit consent to test for HIV and this led to a high refusal rate (13.6%), especially among women from AIDS-endemic countries. After the introduction of the opting-out method, the refusal rate fell from 3% in the first quarter of 2003 to 1.4% in the last quarter of 2003. None of the women refused to be tested for HBV or syphilis. In 2003, the HIV prevalence among pregnant women was 0.3% (35/13.621). The experiences with this screening method in Amsterdam were used to implement the national opting-out method for HIV screening in pregnant women, which was introduced on 1 January 2004.
    Nederlands tijdschrift voor geneeskunde 11/2004; 148(41):2035-7.
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    M J Postma, J M Bos, Ph Beutels, H Schilthuis, J A R van den Hoek
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    ABSTRACT: Estimate cost-effectiveness of vaccination against hepatitis A virus (HAV) for children of ethnic minorities in Amsterdam. Pharmaco-economic analysis is relevant for motivating reimbursement of vaccination costs in the framework of a programmatic approach to vaccination of ethnic minorities. Pharmaco-economic modeling. In cost-effectiveness analysis, costs, benefits and health gains were estimated for a large-scale HAV-vaccination for children of Turkish and Maroccan origin. Analysis was performed from the societal perspective, as recommended in the Dutch guidelines for pharmaco-economic research. This implies that indirect costs of production losses are included in the analysis. Cost-effectiveness was expressed in net costs per adult HAV-infection averted in incremental and aggregate analysis. Incremental analysis compares targeted vaccination with the current limited-scale HAV-vaccination that exists, whereas aggregate analysis compares targeted vaccination with the sheer absence of vaccination. Net aggregate costs of targeted HAV-vaccination for Turkish and Maroccan children in Amsterdam amounts to 61.000. Cost-effectiveness was estimated, in aggregate and incremental analysis, at 13.500 and 11.100 respectively per adult HAV-infection averted. Uni- and multivariate sensitivity analyses show that major impact on cost-effectiveness may be expected from reductions in the vaccine price through economies of scale. Probabilistic sensitivity analysis indicates possible large fluctuations in cost-effectiveness from 1 year to another, related to varying incidence of disease. HAV-vaccination for children from ethnic minorities in Amsterdam is not cost saving, but may have a favourable cost-effectiveness. Such a vaccination program fits into the recent Dutch policy of specific vaccinations directed at groups of ethnic minorities, such as for hepatitis B.
    Vaccine 06/2004; 22(15-16):1862-7. · 3.49 Impact Factor
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    R Welte, M Kretzschmar, J A R van den Hoek, M J Postma
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    ABSTRACT: Cited By (since 1996): 4, Export Date: 25 April 2012, Source: Scopus
    Sexually Transmitted Infections 11/2003; 79(5):426. · 2.61 Impact Factor
  • H Dijkshoorn, H J Schilthuis, J A R van den Hoek, A P Verhoeff
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    ABSTRACT: To determine the travel behaviour of inhabitants of Amsterdam, the Netherlands, with respect to age and ethnicity, as well as the impact of travel advice, in particular regarding hepatitis A vaccination of Turkish and Moroccan children. Descriptive. In a sample of 2000 inhabitants of Amsterdam, a survey was carried out during the period October 1999-November 2000 on seeking medical advice prior to travelling. In addition, 429 Turkish and Moroccan parents were questioned about hepatitis A vaccination of their children when travelling to their country of origin. In the three years preceding the survey one third of the Amsterdam population travelled to a country where infectious diseases such as malaria and hepatitis A were endemic. Many travellers (18%) went to Asia, Central or Latin America and Africa. Others (12%) travelled to the Middle-East or North Africa. One third of the travellers had sought advice from the Municipal Public Health Service of Amsterdam. Other travellers were advised by their general practitioner (10%). A large group (38%) did not seek any advice at all. Almost one third of the travellers went to their country of origin, particularly Turkish and Moroccan inhabitants of Amsterdam. Seventy percent of Turkish and Moroccan travellers had not sought travel advice. More than half the Turkish and Moroccan parents did not have their children vaccinated against hepatitis A when travelling to their country of origin. One fifth of the indigenous Dutch population received no travel advice. More than half of Turkish and Moroccan children travelling to their country of origin were not vaccinated against hepatitis A.
    Nederlands tijdschrift voor geneeskunde 05/2003; 147(14):658-62.
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    ABSTRACT: Dit artikel is gebaseerd op het artikel 'HIV en aids in Nederland: prevalentie en incidentie, 1987-2001 (Ned Tijdschr Geneeskd 2003;147(22):1071-6) 1 en is, waar mogelijk, aangevuld met cijfers over 2002. De bovengenoemde auteurs hebben bijgedragen aan deze cijfers.
    Archives of Internal Medicine - ARCH INTERN MED. 01/2003;
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    ABSTRACT: To determine the incidence of patients reported with typhoid fever in Amsterdam (1991-2000) and to evaluate the contact tracing for those patients with the specific objective of examining whether contact tracing can be simplified. Retrospective. From an automated database, data were collected on all reported typhoid fever patients in Amsterdam during the period 1991-2000 and on their contact persons. One hundred and one patients with typhoid fever were reported during the study period, and Salmonella typhi infection was diagnosed in 12 of the 281 household contacts. For 96 of the 101 index patients, travelling abroad was the most likely source of infection. In 8 of the 12 contact persons with an S. typhi infection, the index person was the most likely source of infection, which is equivalent to a secondary transmission rate of 2.8% (8/277). Seven of the 8 secondary infected persons had symptoms indicative of typhoid fever infection and S. typhi was found in all their first stool samples. Supported by these results, the national guidelines for source and contact tracing in the case of typhoid fever have been amended. In the case of index patients with bad toilet hygiene or who are responsible for food preparation, the faeces of all household contacts must be examined once. If the contact persons have symptoms indicative of an S. typhi infection and/or if their work involves food preparation, their faeces should also be tested once. The changes to the national protocol will markedly reduce the labour-intensity of tracing and testing the contacts of patients with typhoid fever, thereby maintaining the quality of the process. Tracing the source of infection in the case of patients with typhoid fever will also remain important in the future in order to detect potential transmission within the Netherlands at an early stage.
    Nederlands tijdschrift voor geneeskunde 10/2002; 146(39):1833-7.

Publication Stats

292 Citations
40.25 Total Impact Points

Institutions

  • 2002–2009
    • Gezond Amsterdam
      Amsterdamo, North Holland, Netherlands
    • Academisch Medisch Centrum Universiteit van Amsterdam
      Amsterdamo, North Holland, Netherlands
  • 2008
    • University of Groningen
      • Department of Pharmacy
      Groningen, Province of Groningen, Netherlands
  • 2006–2008
    • GGD Amsterdam
      Amsterdamo, North Holland, Netherlands
  • 2002–2006
    • Gemeentelijke Geneeskundige en Gezondheidsdienst
      Utrecht, Utrecht, Netherlands
  • 2004
    • Municipal Health Service of South Netherlands
      Dordt, South Holland, Netherlands
  • 2003
    • Universität Ulm
      Ulm, Baden-Württemberg, Germany