Amsterdam, Netherlands
Amsterdam, Netherlands

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Belderok S.-M.,Public Health Service GGD | van den Hoek A.,Public Health Service GGD | Roeffen W.,Radboud University Nijmegen | Sauerwein R.,Radboud University Nijmegen | And 2 more authors.
PLoS ONE | Year: 2013

Background: We conducted a prospective study in a cohort of short-term travelers assessing the incidence rate of anti-circumsporozoite seroconversion, adherence to chemoprophylaxis, symptoms of malaria during travel, and malaria treatment abroad. Methods: Adults were recruited from the travel clinic of the Public Health Service Amsterdam. They kept a structured daily travel diary and donated blood samples before and after travel. Blood samples were serologically tested for the presence of Plasmodium falciparum anti-circumsporozoite antibodies. Results: Overall, the incidence rate (IR) of anti-circumsporozoite seroconversion was 0.8 per 100 person-months. Of 945 travelers, 620 (66%) visited high-endemic areas and were advised about both chemoprophylaxis and preventive measures against mosquito bites. Most subjects (520/620 = 84%) took at least 75% of recommended prophylaxis during travel. Travel to Africa, use of mefloquine, travel duration of 14-29 days in endemic areas, and concurrent use of DEET (N,N-diethyl-meta-toluamide) were associated with good adherence practices. Four travelers without fever seroconverted, becoming anti-circumsporozoite antibody-positive. All four had been adherent to chemoprophylaxis; two visited Africa, one Suriname, one India. Ten subjects with fever were tested for malaria while abroad and of these, three received treatment. All three were adherent to chemoprophylaxis and tested negative for anti-circumsporozoite antibodies. Conclusion: Travel to Africa, using mefloquine, travel duration of 14-29 days in endemic areas, and use of DEET were associated with good adherence to chemoprophylaxis. The combination of chemoprophylaxis and other preventive measures were sufficient to protect seroconverting travelers from clinical malaria. Travelers who were treated for malaria abroad did not seroconvert. © 2013 Belderok et al.


Elfrink F.,Public Health Service GGD | Elfrink F.,National Coordination Center for Travelers Health Advice | Van Den Hoek A.,Public Health Service GGD | Sonder G.J.B.,Public Health Service GGD | Sonder G.J.B.,National Coordination Center for Travelers Health Advice
Travel Medicine and Infectious Disease | Year: 2014

The number of individuals with a chronic disease increases. Better treatment options have improved chronic patients' quality of life, likely increasing their motivation for travel. This may have resulted in a change in the number of HIV-infected travelers and/or travelers with Diabetes Mellitus (DM) visiting our travel clinic. We retrospectively analyzed the database of the travel clinic of the Public Health Service Amsterdam, between January 2001 and December 2011 and examined the records for patients with these conditions. Of the 25,000 travelers who consult our clinic annually, the proportion of travelers with HIV or DM has increased significantly. A total of 564 HIV-infected travelers visited our clinic. The mean age was 41 years, 86% were male, 43% visited a yellow fever endemic country and 46.5% had a CD4 count <500 cells/mm3. Travelers with low CD4 counts traveled significantly more often to visit friends or relatives. A total of 3704 diabetics visited our clinic. The mean age was 55 years, 52% were male, 27% visited a yellow fever endemic country and 36% were insulin-dependent. Insulin-dependent diabetics traveled more often for work than non-insulin-dependent diabetics. Adequately trained and qualified travel health professionals and up-to-date guidelines for travelers with chronic diseases are of increasing importance. © 2013 Published by Elsevier Ltd.


Overbosch F.W.,National Coordination Center for Travelers Health Advice | Overbosch F.W.,Public Health Service GGD | Koeman S.C.,National Coordination Center for Travelers Health Advice | Van Den Hoek A.,Public Health Service GGD | And 2 more authors.
Journal of Travel Medicine | Year: 2012

Background. In travel medicine, as in other specialties, independent prescribing of medication has traditionally been the domain of practitioners like physicians, dentists, and midwives. However, a 2011 ruling in the Netherlands expands independent prescribing and introduces supplementary prescribing by nurses, with expected implementation over the next few years. As specialist nurses will not be eligible for independent prescribing, this study addresses supplementary prescribing, specifically by travel health nurses. Such nurses will work in partnership with an independent prescriber, usually a physician. After the physician evaluates a patient's condition and needs, the nurse may prescribe from an open or limited formulary. This supplementary approach seems appropriate in travel medicine, which is highly protocolized. A questionnaire survey was conducted to assess whether travel health nurses themselves aspire and feel competent to prescribe, and what training they might need. Methods. All travel health nurses in the Netherlands received a questionnaire seeking their anonymous response. Results. The response rate was 58%. Self-reported compliance with protocols and quality criteria was high; 82% of respondents aspire to prescribe and 77% feel competent to prescribe. Of the latter, 22% indicated that ongoing access to a doctor would remain important, and 14% preferred to prescribe under certain conditions like a restricted number of medicines. The reason most frequently given for not feeling competent was the need for additional education before obtaining prescribing rights (40%). Aspiration to prescribe was the only significant predictor for feeling competent to prescribe (odds ratios: 6.8; 95% confidence intervals: 3.5-13). Of all the responding nurses, 95% reported one or more educational needs related to prescribing, particularly in pharmacology. Conclusions. Most Dutch travel health nurses aspire to prescribe and feel competent for the supplementary approach, but require further education before the approach is implemented in travel medicine. © 2012 GGD Amsterdam, 1195-1982.


Belderok S.-M.,Public Health Service GGD | van den Hoek A.,Public Health Service GGD | Kint J.A.,Public Health Service GGD | Schim van der Loeff M.F.,Public Health Service GGD | And 2 more authors.
BMC Infectious Diseases | Year: 2011

Background: Travellers' diarrhoea (TD) is the most common infectious disease among travellers. In the Netherlands, stand-by or prophylactic antibiotics are not routinely prescribed to travellers. This study prospectively assessed the incidence rate, risk factors, and treatment of TD among immunocompetent travellers.Methods: Persons who attended the travel clinic of the Public Health Service Amsterdam in 2006-2007 before short-term travel to tropical and subtropical countries were invited to answer a questionnaire regarding sociodemographics and travel purpose; they were also asked to keep a daily structured travel diary, recording their itinerary, symptoms, and self-medication or consultation with a doctor. Diarrhoea episodes containing blood or mucous were considered severe.Results: Of 1202 travellers, the median age was 38 years, and the median travel duration 3 weeks. Of all episodes, 96% were mild. The median duration of TD was 2 days and significantly shorter in subsequent episodes compared to first episodes (p < 0.0005). Of first episodes 38% started in the first travel week. The incidence rate (IR) for first episodes was 2.49 (95% confidence interval [CI], 2.30-2.70) per 100 travel days, with the highest IR among travellers to South-Central and West Asia. The IR for first and subsequent episodes was comparable. Risk factors for first episodes included female sex, a Western country of birth, and tourism as the purpose of travel. The lowest risk was in travellers to South America. An independent risk factor for subsequent episodes was female sex. In total, 5% of travellers used antibiotics; of those, 92% had mild diarrhoea, and 53% received antibiotics over the counter.Conclusions: TD is common among travellers, but the overall course is mild, not requiring treatment. The incidence rates for first and second episodes are comparable. Female sex is a risk factor for the first episode, as well as subsequent ones. Prescription antibiotics are not needed in short-term healthy travellers. © 2011 Belderok et al; licensee BioMed Central Ltd.


Elfrink F.,Public Health Service GGD | Elfrink F.,National Coordination Center for Travellers Health Advice | van den Hoek A.,Public Health Service GGD | Mensen M.E.,Public Health Service GGD | And 2 more authors.
BMC Infectious Diseases | Year: 2014

Background: International travel from low-incidence to high-incidence countries for tuberculosis (TB) is regarded as a risk factor for acquiring TB infection. In this prospective study among long-term travellers we examined the incidence of TB infection using Interferon gamma release assay (IGRA) test and compared these data with results from a visit to the TB department to which all long-term travellers were routinely referred.Methods: Immunocompetent adults, travelling for 13-52 weeks to TB-endemic countries, donated blood pre- and post-travel for IGRA. The pre-travel IGRA was only tested in case of a positive IGRA post-travel. Results from their visit(s) to the TB department for TST pre- and post-travel were collected and compared with study results.Results: We found two IGRA conversions in a group of 516 travellers, resulting in an attack rate (AR) of 0.4% (95% CI: 0.5 - 13.9) and an incidence rate (IR) of 0.85 per 1000 person-months (95% CI: 0.1-3.1).We found 5 tuberculin skin test (TST) conversions, resulting in AR of 1.9% (5/261; 95% CI: 0.6 - 4.4) and an IR of 4.26 per 1000 person-months (95% CI: 1.38- 9.94). In our study these converters all had a negative IGRA. One traveller however, who was retested later at the TB department due to a positive TST, then appeared to have seroconverted.Conclusions: The risk of long-term travellers among our study population acquiring TB infection is low. We conclude that post-travel IGRA alone could be used for screening for TB infection among long-term travellers to high-endemic TB countries, but preferably not earlier than 8 weeks after return. One might even argue that IGRA testing should be limited to only those travellers who are going to work in a medical setting. A person with a positive IGRA should be referred to a TB physician for further evaluation. © 2014 Elfrink et al.; licensee BioMed Central Ltd.


Overbosch F.W.,Public Health Service GGD
BMC infectious diseases | Year: 2014

A substantial portion of Dutch travellers is comprised of immigrants returning to their country of origin to visit friends and relatives (VFRs), including VFRs returning to dengue-endemic areas such as Suriname. Limited attention has been focused on dengue among immigrants, therefore it is unknown whether immigration has effect on the epidemiology of (severe) dengue among VFRs.To get more insight in the seroprevalence of dengue among Surinamese immigrants, we conducted a seroprevalence study on a convenience sample of first-generation Surinamese immigrants living in the Netherlands. Blood samples were tested for IgG antibodies to DENV antigen serotypes (1, 2, 3 and 4). Gender, age, years lived in Suriname before immigration, history of yellow fever vaccination, and time between yellow fever vaccination and blood sample collection were examined as possible predictors for previous infection. Of the studied 400 Surinamese travellers with a mean age of 52 years (range 18-89), 37% were male. Serology suggestive of past DENV infection was found in 325 individuals (81.3%; 95% CI: 77-85%). The time lived in Suriname before immigration was the only significant predictor for previous DENV infection. Most first-generation Surinamese immigrants have evidence of past DENV infection, probably comparable to Surinamese inhabitants. Whether this influences the number of cases of (severe) dengue when travelling requires more study.


Lemmert M.E.,Maastricht University | De Vreede-Swagemakers J.J.M.,Public Health Service GGD | Eurlings L.W.M.,Maastricht University | Kalb L.,Maastricht University | And 3 more authors.
American Journal of Cardiology | Year: 2012

Sudden cardiac arrest (SCA), due mainly to coronary artery disease (CAD), is a leading cause of death. To identify electrocardiographic and clinical differences between patients with CAD with and without SCA, 87 victims of SCA with CAD were compared with 131 patients with CAD without SCA. Patients' latest routine electrocardiograms and clinical variables were compared. Patients with CAD with and without previous myocardial infarctions (MIs) were included. Patients with SCA had a higher incidence of echocardiographic evidence of left ventricular hypertrophy and/or heart failure than controls. The median left ventricular ejection fractions for patients with SCA with and without previous MIs were 0.30 (interquartile range 0.24 to 0.41) and 0.41 (interquartile range 0.25 to 0.56). The median time between the last electrocardiographic assessment and SCA was 59 days (interquartile range 29 to 137). Regarding electrocardiographic characteristics, in patients with and without previous MIs, QRS width (odds ratio 1.032, 95% confidence interval 1.012 to 1.053, p = 0.002, and odds ratio 1.035, 95% confidence interval 1.015 to 1.056, p = 0.001) was the only significant predictor of SCA. In conclusion, in patients with CAD, regardless of a previous MI, a longer QRS width and echocardiographic parameters consistent with heart failure are associated with SCA, even in patients with ischemic cardiomyopathy currently not eligible for an implantable cardioverter-defibrillator. © 2012 Elsevier Inc. All rights reserved.


PubMed | Public Health Service GGD
Type: Clinical Trial, Phase IV | Journal: Vaccine | Year: 2013

A phase IV interventional study with a combined hepatitis A and B vaccine was conducted in HIV-infected children and children receiving immunosuppressive medication for treatment of rheumatic diseases to evaluate immune responses.Both groups (1-16 years of age) received combined (inactivated) HAV and (rDNA) HBV vaccine Ambirix() at months 0 and 6. Serum samples were taken at four time points and tested for anti-HAV and anti-HBs antibodies. Anti-HAV concentrations 20 mIU/mL or anti-HBs concentrations 10 mIU/mL were considered protective. Seropositivity percentages were calculated and geometric mean concentrations (GMCs) were compared by nonparametric Mann-Whitney U-test or Kruskal-Wallis one-way-analysis-of-variance.Of 80 HIV-infected children who completed the study, 67 were HAV-susceptible and 68 HBV-susceptible at enrolment. Of 80 children with rheumatic diseases who completed the study, 65 were HAV-susceptible and 74 HBV-susceptible at enrolment. Immune responses to HAV after first dose of vaccine in both study groups were low: 71% and 55% respectively, whereas immune responses after the second dose were 99% and 100% respectively. Immune response to HBV after first dose of vaccine in both groups was also low: 27% and 17% respectively. Immune responses after the second dose were 97% and 93%, respectively. A larger proportion of children on combination antiretroviral therapy (cART) and of children with viral load <50 copies/mL responded to HBV, and also showed a significantly higher GMC.Although immune response after full series of combined HAV and HBV vaccine in both groups was excellent and comparable to healthy children, a substantial proportion of both groups was not protected for HAV after first dose of vaccine. This protection gap is especially important for HAV in travel health and postexposure prophylactic treatment: both groups of children should be serologically tested for anti-HAV prior to travel to ensure protection if there is no time to await second dose of vaccine.


International travel from low-incidence to high-incidence countries for tuberculosis (TB) is regarded as a risk factor for acquiring TB infection. In this prospective study among long-term travellers we examined the incidence of TB infection using Interferon gamma release assay (IGRA) test and compared these data with results from a visit to the TB department to which all long-term travellers were routinely referred.Immunocompetent adults, travelling for 13-52 weeks to TB-endemic countries, donated blood pre- and post-travel for IGRA. The pre-travel IGRA was only tested in case of a positive IGRA post-travel. Results from their visit(s) to the TB department for TST pre- and post-travel were collected and compared with study results.We found two IGRA conversions in a group of 516 travellers, resulting in an attack rate (AR) of 0.4% (95% CI: 0.5 - 13.9) and an incidence rate (IR) of 0.85 per 1000 person-months (95% CI: 0.1-3.1).We found 5 tuberculin skin test (TST) conversions, resulting in AR of 1.9% (5/261; 95% CI: 0.6 - 4.4) and an IR of 4.26 per 1000 person-months (95% CI: 1.38- 9.94). In our study these converters all had a negative IGRA. One traveller however, who was retested later at the TB department due to a positive TST, then appeared to have seroconverted.The risk of long-term travellers among our study population acquiring TB infection is low. We conclude that post-travel IGRA alone could be used for screening for TB infection among long-term travellers to high-endemic TB countries, but preferably not earlier than 8weeks after return. One might even argue that IGRA testing should be limited to only those travellers who are going to work in a medical setting. A person with a positive IGRA should be referred to a TB physician for further evaluation.


PubMed | Public Health Service GGD, National Research Council Italy, University of Stockholm and King's College London
Type: | Journal: Environment international | Year: 2016

This study reports the first investigation of atmospheric illicit drug concentrations in Northern Europe using measurements of cocaine and cannabinoids in Amsterdam, London and Stockholm. Further, these measurements were compared to those made in Rome to explore the geographical and inter-city variability. Co-located measurements of atmospheric particulate mass and PAHs were used to help describe and interpret the illicit drug measurements with respect to atmospheric dispersion. Cocaine concentrations ranged from 0.03 to 0.14ng/m

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