Cees C van den Wijngaard

Publications

• 4.41

  Impact points

  Comparing pandemic to seasonal influenza mortality: moderate impact overall but high mortality in young children.

  Cees C van den Wijngaard, Liselotte van Asten, Marion P G Koopmans, Wilfrid van Pelt, Nico J D Nagelkerke, Cornelia C H Wielders, Alies van Lier, Wim van der Hoek, Adam Meijer, Gé A Donker, Frederika Dijkstra, Carel Harmsen, Marianne A B van der Sande, Mirjam Kretzschmar

  PloS one. 01/2012; 7(2):e31197.

  We assessed the severity of the 2009 influenza pandemic by comparing pandemic mortality to seasonal influenza mortality. However, reported pandemic deaths were laboratory-confirmed - and thus an underestimation - whereas seasonal influenza mortality is often more inclusively estimated. For a valid c... [more] We assessed the severity of the 2009 influenza pandemic by comparing pandemic mortality to seasonal influenza mortality. However, reported pandemic deaths were laboratory-confirmed - and thus an underestimation - whereas seasonal influenza mortality is often more inclusively estimated. For a valid comparison, our study used the same statistical methodology and data types to estimate pandemic and seasonal influenza mortality. We used data on all-cause mortality (1999-2010, 100% coverage, 16.5 million Dutch population) and influenza-like-illness (ILI) incidence (0.8% coverage). Data was aggregated by week and age category. Using generalized estimating equation regression models, we attributed mortality to influenza by associating mortality with ILI-incidence, while adjusting for annual shifts in association. We also adjusted for respiratory syncytial virus, hot/cold weather, other seasonal factors and autocorrelation. For the 2009 pandemic season, we estimated 612 (range 266-958) influenza-attributed deaths; for seasonal influenza 1,956 (range 0-3,990). 15,845 years-of-life-lost were estimated for the pandemic; for an average seasonal epidemic 17,908. For 0-4 yrs of age the number of influenza-attributed deaths during the pandemic were higher than in any seasonal epidemic; 77 deaths (range 61-93) compared to 16 deaths (range 0-45). The ≥75 yrs of age showed a far below average number of deaths. Using pneumonia/influenza and respiratory/cardiovascular instead of all-cause deaths consistently resulted in relatively low total pandemic mortality, combined with high impact in the youngest age category. The pandemic had an overall moderate impact on mortality compared to 10 preceding seasonal epidemics, with higher mortality in young children and low mortality in the elderly. This resulted in a total number of pandemic deaths far below the average for seasonal influenza, and a total number of years-of-life-lost somewhat below average. Comparing pandemic and seasonal influenza mortality as in our study will help assessing the worldwide impact of the 2009 pandemic.

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• 5.51

  Impact points

  Unspecified gastroenteritis illness and deaths in the elderly associated with norovirus epidemics.

  Liselotte van Asten, Joukje Siebenga, Cees van den Wijngaard, Robert Verheij, Hans van Vliet, Mirjam Kretzschmar, Hendriek Boshuizen, Wilfrid van Pelt, Marion Koopmans

  Epidemiology (Cambridge, Mass.). 02/2011; 22(3):336-43.

  New variant strains of norovirus have emerged worldwide in recent years, evolving by mutation much like influenza viruses. These strains have been associated with a notable increase in the number of annual norovirus outbreaks. However, the impact of such increased norovirus activity on morbidity and... [more] New variant strains of norovirus have emerged worldwide in recent years, evolving by mutation much like influenza viruses. These strains have been associated with a notable increase in the number of annual norovirus outbreaks. However, the impact of such increased norovirus activity on morbidity and mortality is not clear because norovirus infection is rarely specifically registered. We studied trends of gastroenteritis with unspecified cause in medical registrations (ie, general practitioner [GP] visits, hospitalizations, and deaths) and their association with known temporal trends in norovirus outbreaks in the Netherlands. Using weekly counts in the elderly (aged 65+ years) from 1999 through 2006, we applied Poisson regression analyses adjusted for additional pathogens and seasonal trends (linear, sine, and cosine terms). In the elderly, each notified norovirus outbreak was associated with an estimated 26 unspecified gastroenteritis GP visits (95% confidence interval = 17-34), 2.2 unspecified gastroenteritis hospitalizations (1.6-2.7), and 0.14 unspecified gastroenteritis deaths (0.08-0.21). For the heaviest norovirus season (2004-2005), these models attributed up to 3804 unspecified gastroenteritis GP visits, 318 unspecified gastroenteritis hospitalizations, and 21 unspecified gastroenteritis deaths to norovirus outbreaks among a total elderly population of 2.3 million. The recent increase in norovirus outbreak activity is associated with increases of unspecified gastroenteritis morbidity and even deaths in the elderly. Norovirus should not be regarded as an infection with trivial health risks.
• 2.37

  Impact points

  In search of hidden Q-fever outbreaks: linking syndromic hospital clusters to infected goat farms.

  C C van den Wijngaard, F Dijkstra, W van Pelt, L van Asten, M Kretzschmar, B Schimmer, N J D Nagelkerke, P Vellema, G A Donker, M P G Koopmans

  Epidemiology and infection. 01/2011; 139(1):19-26.

  Large Q-fever outbreaks were reported in The Netherlands from May 2007 to 2009, with dairy-goat farms as the putative source. Since Q-fever outbreaks at such farms were first reported in 2005, we explored whether there was evidence of human outbreaks before May 2007. Space-time scan statistics were ... [more] Large Q-fever outbreaks were reported in The Netherlands from May 2007 to 2009, with dairy-goat farms as the putative source. Since Q-fever outbreaks at such farms were first reported in 2005, we explored whether there was evidence of human outbreaks before May 2007. Space-time scan statistics were used to look for clusters of lower-respiratory infections (LRIs), hepatitis, and/or endocarditis in hospitalizations, 2005-2007. We assessed whether these were plausibly caused by Q fever, using patients' age, discharge diagnoses, indications for other causes, and overlap with reported Q fever in goats/humans. For seven detected LRI clusters and one hepatitis cluster, we considered Q fever a plausible cause. One of these clusters reflected the recognized May 2007 outbreak. Real-time syndromic surveillance would have detected four of the other clusters in 2007, one in 2006 and two in 2005, which might have resulted in detection of Q-fever outbreaks up to 2 years earlier.

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• 2.31

  Impact points

  The burden of 2009 pandemic influenza A(H1N1) in the Netherlands.

  C C H Wielders, E A van Lier, T M van 't Klooster, A B van Gageldonk-Lafeber, C C van den Wijngaard, J A Haagsma, G A Donker, A Meijer, W van der Hoek, A K Lugnér, M E E Kretzschmar, M A B van der Sande

  European journal of public health. 12/2010; 22(1):150-7.

  The disease burden of the 2009 influenza pandemic has been debated but reliable estimates are lacking. To guide future policy and control, these estimates are necessary. This study uses burden of disease measurements to assess the contribution of the pandemic influenza A(H1N1) virus to the overall b... [more] The disease burden of the 2009 influenza pandemic has been debated but reliable estimates are lacking. To guide future policy and control, these estimates are necessary. This study uses burden of disease measurements to assess the contribution of the pandemic influenza A(H1N1) virus to the overall burden of disease in the Netherlands. The burden of disease caused by 2009 pandemic influenza was estimated by calculating Disability Adjusted Life Years (DALY), a composite measure that combines incidence, sequelae and mortality associated with a disease, taking duration and severity into account. Available influenza surveillance data sources (primary care sentinel surveillance, notification data on hospitalizations and deaths and death registries) were used. Besides a baseline scenario, five alternative scenarios were used to assess effects of changing values of input parameters. The baseline scenario showed a loss of 5800 DALY for the Netherlands (35 DALY per 100 000 population). This corresponds to 0.13% of the estimated annual disease burden in the Netherlands and is comparable to the estimated disease burden of seasonal influenza, despite a different age distribution in incidence and mortality of the pandemic compared to seasonal influenza. This disease burden estimate confirmed that, although there was a higher mortality observed among young people, the 2009 pandemic was overall a mild influenza epidemic. The disease burden of this pandemic was comparable to the burden of seasonal influenza in the Netherlands.

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• 4.37

  Impact points

  Detection of excess influenza severity: associating respiratory hospitalization and mortality data with reports of influenza-like illness by primary care physicians.

  Cees C van den Wijngaard, Liselotte van Asten, Adam Meijer, Wilfrid van Pelt, Nico J D Nagelkerke, Gé A Donker, Marianne A B van der Sande, Marion P G Koopmans

  American journal of public health. 11/2010; 100(11):2248-54.

  We explored whether excesses in influenza severity can be detected by combining respiratory syndromic hospital and mortality data with data on influenza-like illness (ILI) cases obtained from general practitioners. To identify excesses in the severity of influenza infections in the population of the... [more] We explored whether excesses in influenza severity can be detected by combining respiratory syndromic hospital and mortality data with data on influenza-like illness (ILI) cases obtained from general practitioners. To identify excesses in the severity of influenza infections in the population of the Netherlands between 1999 and 2005, we looked for increases in influenza-associated hospitalizations and mortality that were disproportionate to the number of ILI cases reported by general practitioners. We used generalized estimating equation regression models to associate syndromic hospital and mortality data with ILI surveillance data obtained from general practitioners. Virus isolation and antigenic characterization data were used to interpret the results. Disproportionate increases in hospitalizations and mortality (relative to ILI cases reported by general practitioners) were identified in 2003/04 during the A/Fujian/411/02(H3N2) drift variant epidemic. Combined surveillance of respiratory hospitalizations and mortality and ILI data obtained from general practitioners can capture increases in severe influenza-associated illness that are disproportionate to influenza incidence rates. Therefore, this novel approach should complement traditional seasonal and pandemic influenza surveillance in efforts to detect increases in influenza case fatality rates and percentages of patients hospitalized.

• Surveillance of hospitalisations for 2009 pandemic influenza A(H1N1) in the Netherlands, 5 June - 31 December 2009.

  T M van 't Klooster, C C Wielders, T Donker, L Isken, A Meijer, C C van den Wijngaard, M A van der Sande, W van der Hoek

  Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin. 01/2010; 15(2).

  We analysed and reported on a weekly basis clinical and epidemiological characteristics of patients hospitalised in the Netherlands for the 2009 pandemic influenza A(H1N1) using information from the national mandatory notification system. The notification criteria changed on 15 August 2009 from all ... [more] We analysed and reported on a weekly basis clinical and epidemiological characteristics of patients hospitalised in the Netherlands for the 2009 pandemic influenza A(H1N1) using information from the national mandatory notification system. The notification criteria changed on 15 August 2009 from all possible, probable and confirmed cases to only laboratory-confirmed pandemic influenza hospitalisations and deaths. In the period of comprehensive case-based surveillance (until 15 August), 2% (35/1,622) of the patients with pandemic influenza were hospitalised. From 5 June to 31 December 2009, a total of 2,181 patients were hospitalised. Of these, 10% (219/2,181) were admitted to an intensive care unit (ICU) and 53 died. Among non-ICU hospitalised patients, 56% (961/1,722) had an underlying medical condition compared with 70% (147/211) of the patients in ICU and 46 of the 51 fatal cases for whom this information was reported. Most common complications were dehydration among non-ICU hospitalised patients and acute respiratory distress syndrome among patients in ICU and patients who died. Children under the age of five years had the highest age-specific hospitalisation rate (62.7/100,000), but relatively few were admitted to an ICU (1.7/100,000). Characteristics and admission rates of hospitalised patients were comparable with reports from other countries and previous influenza seasons. The national notification system was well suited to provide weekly updates of relevant monitoring information on the severity of the pandemic for professionals, decision makers, the media and the public, and could be rapidly adapted to changing information requirements.
• 4.41

  Impact points

  Syndromic surveillance for local outbreaks of lower-respiratory infections: would it work?

  Cees C van den Wijngaard, Liselotte van Asten, Wilfrid van Pelt, Gerda Doornbos, Nico J D Nagelkerke, Gé A Donker, Wim van der Hoek, Marion P G Koopmans

  PloS one. 01/2010; 5(4):e10406.

  Although syndromic surveillance is increasingly used to detect unusual illness, there is a debate whether it is useful for detecting local outbreaks. We evaluated whether syndromic surveillance detects local outbreaks of lower-respiratory infections (LRIs) without swamping true signals by false alar... [more] Although syndromic surveillance is increasingly used to detect unusual illness, there is a debate whether it is useful for detecting local outbreaks. We evaluated whether syndromic surveillance detects local outbreaks of lower-respiratory infections (LRIs) without swamping true signals by false alarms. Using retrospective hospitalization data, we simulated prospective surveillance for LRI-elevations. Between 1999-2006, a total of 290762 LRIs were included by date of hospitalization and patients place of residence (>80% coverage, 16 million population). Two large outbreaks of Legionnaires disease in the Netherlands were used as positive controls to test whether these outbreaks could have been detected as local LRI elevations. We used a space-time permutation scan statistic to detect LRI clusters. We evaluated how many LRI-clusters were detected in 1999-2006 and assessed likely causes for the cluster-signals by looking for significantly higher proportions of specific hospital discharge diagnoses (e.g. Legionnaires disease) and overlap with regional influenza elevations. We also evaluated whether the number of space-time signals can be reduced by restricting the scan statistic in space or time. In 1999-2006 the scan-statistic detected 35 local LRI clusters, representing on average 5 clusters per year. The known Legionnaires' disease outbreaks in 1999 and 2006 were detected as LRI-clusters, since cluster-signals were generated with an increased proportion of Legionnaires disease patients (p:<0.0001). 21 other clusters coincided with local influenza and/or respiratory syncytial virus activity, and 1 cluster appeared to be a data artifact. For 11 clusters no likely cause was defined, some possibly representing as yet undetected LRI-outbreaks. With restrictions on time and spatial windows the scan statistic still detected the Legionnaires' disease outbreaks, without loss of timeliness and with less signals generated in time (up to 42% decline). To our knowledge this is the first study that systematically evaluates the performance of space-time syndromic surveillance with nationwide high coverage data over a longer period. The results show that syndromic surveillance can detect local LRI-outbreaks in a timely manner, independent of laboratory-based outbreak detection. Furthermore, since comparatively few new clusters per year were observed that would prompt investigation, syndromic hospital-surveillance could be a valuable tool for detection of local LRI-outbreaks.

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• 13.05

  Impact points

  Geographic distribution of Staphylococcus aureus causing invasive infections in Europe: a molecular-epidemiological analysis.

  Hajo Grundmann, David M Aanensen, Cees C van den Wijngaard, Brian G Spratt, Dag Harmsen, Alexander W Friedrich

  PLoS medicine. 01/2010; 7(1):e1000215.

  Staphylococcus aureus is one of the most important human pathogens and methicillin-resistant variants (MRSAs) are a major cause of hospital and community-acquired infection. We aimed to map the geographic distribution of the dominant clones that cause invasive infections in Europe. In each country, ... [more] Staphylococcus aureus is one of the most important human pathogens and methicillin-resistant variants (MRSAs) are a major cause of hospital and community-acquired infection. We aimed to map the geographic distribution of the dominant clones that cause invasive infections in Europe. In each country, staphylococcal reference laboratories secured the participation of a sufficient number of hospital laboratories to achieve national geo-demographic representation. Participating laboratories collected successive methicillin-susceptible (MSSA) and MRSA isolates from patients with invasive S. aureus infection using an agreed protocol. All isolates were sent to the respective national reference laboratories and characterised by quality-controlled sequence typing of the variable region of the staphylococcal spa gene (spa typing), and data were uploaded to a central database. Relevant genetic and phenotypic information was assembled for interactive interrogation by a purpose-built Web-based mapping application. Between September 2006 and February 2007, 357 laboratories serving 450 hospitals in 26 countries collected 2,890 MSSA and MRSA isolates from patients with invasive S. aureus infection. A wide geographical distribution of spa types was found with some prevalent in all European countries. MSSA were more diverse than MRSA. Genetic diversity of MRSA differed considerably between countries with dominant MRSA spa types forming distinctive geographical clusters. We provide evidence that a network approach consisting of decentralised typing and visualisation of aggregated data using an interactive mapping tool can provide important information on the dynamics of MRSA populations such as early signalling of emerging strains, cross border spread, and importation by travel. In contrast to MSSA, MRSA spa types have a predominantly regional distribution in Europe. This finding is indicative of the selection and spread of a limited number of clones within health care networks, suggesting that control efforts aimed at interrupting the spread within and between health care institutions may not only be feasible but ultimately successful and should therefore be strongly encouraged.
• 3.12

  Impact points

  Strengthening the diagnostic capacity to detect Bio Safety Level 3 organisms in unusual respiratory viral outbreaks.

  Liselotte van Asten, Mariken van der Lubben, Cees van den Wijngaard, Wilfrid van Pelt, Robert Verheij, Andre Jacobi, Pieter Overduin, Adam Meijer, Dirk Luijt, Eric Claas, [......], Charles Bouchier, Jurjen Schirm, Louis Kroes, Sander Leenders, Joep Galama, Marcel Peeters, Anton van Loon, Ellen Stobberingh, Martin Schutten, Marion Koopmans D V M

  Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology. 07/2009;

  BACKGROUND: Experience with a highly pathogenic avian influenza outbreak in the Netherlands (2003) illustrated that the diagnostic demand for respiratory viruses at different biosafety levels (including BSL3), can increase unexpectedly and dramatically. OBJECTIVES: We describe the measures taken sin... [more] BACKGROUND: Experience with a highly pathogenic avian influenza outbreak in the Netherlands (2003) illustrated that the diagnostic demand for respiratory viruses at different biosafety levels (including BSL3), can increase unexpectedly and dramatically. OBJECTIVES: We describe the measures taken since, aimed at strengthening national laboratory surge capacity and improving preparedness for dealing with diagnostic demand during outbreaks of (emerging) respiratory virus infections, including pandemic influenza virus. STUDY DESIGN: Academic and peripheral medical-microbiological laboratories collaborated to determine minimal laboratory requirements for the identification of viruses in the early stages of a pandemic or a large outbreak of avian influenza virus. Next, an enhanced collaborative national network of outbreak assistance laboratories (OAL) was set up. An inventory was made of the maximum diagnostic throughput that this network can deliver in a period of intensified demand. For an estimate of the potential magnitude of this surge demand, historical counts were calculated from hospital- and physician-based registries of patients presenting with respiratory symptoms. RESULTS: Number of respiratory physician-visits ranged from 140,000 to 615,000 per month and hospitalizations ranged from 3000 to 11,500 per month. The established OAL-network provides rapid diagnostic response with agreed quality requirements and a maximum throughput capacity of 1275 samples/day (38,000 per month), assuming other routine diagnostic work needs to be maintained. CONCLUSIONS: Thus surge demand for diagnostics for hospitalized cases (if not distinguishable from other respiratory illness) could be handled by the OAL network. Assessing etiology of community acquired acute respiratory infection however, may rapidly exceed the capacity of the network. Therefore algorithms are needed for triaging for laboratory diagnostics; currently this is not addressed in pandemic preparedness plans.

• [New influenza A (H1N1): advised indication and prescription of antiviral drugs]

  C C Kees van den Wijngaard, Jim E van Steenbergen, Marianne A B van der Sande, Marion P G Koopmans

  Nederlands tijdschrift voor geneeskunde. 01/2009; 153.

  AIM: To evaluate to what extent antiviral drugs have been prescribed to patients other than confirmed cases and their contacts since the emergence of New Influenza A (H1N1). DESIGN: Descriptive. METHODS: We inspected monthly and annual counts of oseltamivir (Tamiflu) and zanamivir (Relenza) prescrip... [more] AIM: To evaluate to what extent antiviral drugs have been prescribed to patients other than confirmed cases and their contacts since the emergence of New Influenza A (H1N1). DESIGN: Descriptive. METHODS: We inspected monthly and annual counts of oseltamivir (Tamiflu) and zanamivir (Relenza) prescriptions dispensed by public pharmacies in the Netherlands from 2005 until 30 June 2009. We compared these figures with counts of antiviral cures supplied by the Netherlands Vaccine Institute (NVI) to Municipal Health Services (GGDs) for the treatment of confirmed cases and contacts up until 1 July 2009. RESULTS: Counts of oseltamivir prescriptions dispensed by public pharmacies started to increase in April 2009. Although this increase might seem limited compared to increases in 2005/2006 triggered by avian influenza in Turkey, up to 1 July 2009 oseltamivir was dispensed 9069 times, which is 9 times more often than in 2007 and 15 times more often than in 2008. This total was also approximately 10 times more than that dispensed by Municipal Health Services to confirmed cases of H1N1 infection and their contacts. General practitioners prescribed 78% of the prescriptions dispensed. Counts of zanamivir prescriptions dispensed hardly increased. CONCLUSION: The counts of oseltamivir prescriptions dispensed by Dutch public pharmacies has increased, even though patients with a confirmed H1N1 infection and their contacts had already been treated by the Municipal Health Services. Therefore it cannot be excluded that this increase is due to prescription on a precautionary basis. To avoid unnecessary risks for the spread of resistant strains and a shortage of antivirals later in the epidemic, physicians should refrain from prescribing antiviral drugs if patients do not match the nationally advised medical grounds for treatment.
• 6.79

  Impact points

  Validation of syndromic surveillance for respiratory pathogen activity.

  Cees van den Wijngaard, Liselotte van Asten, Wilfrid van Pelt, Nico J D Nagelkerke, Robert Verheij, Albert J de Neeling, Arnold Dekkers, Marianne A B van der Sande, Hans van Vliet, Marion P G Koopmans

  Emerging infectious diseases. 07/2008; 14(6):917-25.

  Syndromic surveillance is increasingly used to signal unusual illness events. To validate data-source selection, we retrospectively investigated the extent to which 6 respiratory syndromes (based on different medical registries) reflected respiratory pathogen activity. These syndromes showed higher ... [more] Syndromic surveillance is increasingly used to signal unusual illness events. To validate data-source selection, we retrospectively investigated the extent to which 6 respiratory syndromes (based on different medical registries) reflected respiratory pathogen activity. These syndromes showed higher levels in winter, which corresponded with higher laboratory counts of Streptococcus pneumoniae, respiratory syncytial virus, and influenza virus. Multiple linear regression models indicated that most syndrome variations (up to 86%) can be explained by counts of respiratory pathogens. Absenteeism and pharmacy syndromes might reflect nonrespiratory conditions as well. We also observed systematic syndrome elevations in the fall, which were unexplained by pathogen counts but likely reflected rhinovirus activity. Earliest syndrome elevations were observed in absenteeism data, followed by hospital data (+1 week), pharmacy/general practitioner consultations (+2 weeks), and deaths/laboratory submissions (test requests) (+3 weeks). We conclude that these syndromes can be used for respiratory syndromic surveillance, since they reflect patterns in respiratory pathogen activity.
• 2.61

  Impact points

  Syndromic surveillance in the Netherlands for the early detection of West Nile virus epidemics.

  Barry Rockx, Liselotte van Asten, Cees van den Wijngaard, Gert-Jan Godeke, Lutz Goehring, Harry Vennema, Harrie van der Avoort, Wilfrid van Pelt, Marion Koopmans

  Vector borne and zoonotic diseases (Larchmont, N.Y.). 02/2006; 6(2):161-9.

  West Nile virus (WNV) is an arthropod-borne flavivirus that is endemic in Africa, Europe, and Eastern Asia. The recent introduction and rapid dissemination of the virus in the United States as well as an increase in WNV outbreaks in Europe, has raised concerns for its spread in Europe. A surveillanc... [more] West Nile virus (WNV) is an arthropod-borne flavivirus that is endemic in Africa, Europe, and Eastern Asia. The recent introduction and rapid dissemination of the virus in the United States as well as an increase in WNV outbreaks in Europe, has raised concerns for its spread in Europe. A surveillance system was developed to allow timely detection of an introduction of WNV infections in The Netherlands. This program focuses on cases presenting with neurological disease and includes the monitoring of hospital discharge diagnoses, trends in cerebrospinal fluid (CSF) diagnostic requests, laboratory testing of CSF, and monitoring of neurological disease in horses. Retrospective data from the hospital discharge records showed yearly peaks of unexplained meningitis and (meningo)encephalitis in the summer. A total of 781 CSF samples from humans and 71 serum and/or CSF samples from horses presenting with neurological disease of suspected viral etiology tested negative for the presence of specific antibodies to WNV. With a coverage rate of 59% in 2003, the probability that a cluster of five WNV cases presenting with neurological symptoms would have been detected was 99%. We conclude that, from 1999 to 2004, no evidence of WNV infection could be found in either humans or horses in The Netherlands.

• [Syndromic surveillance for the detection of outbreaks of unusual infectious diseases]

  C C van den Wijngaard, L. van Asten, J A van Vliet, W van Pelt, M Koopmans

  Nederlands tijdschrift voor geneeskunde. 11/2005; 149(40):2243-5.

  Syndromic surveillance has been developed in order to detect outbreaks of unusual infectious diseases such as severe acute respiratory syndrome (SARS) or anthrax at an early stage. Whereas the usual surveillance systems are based on established diagnoses and emergency department discharge data, synd... [more] Syndromic surveillance has been developed in order to detect outbreaks of unusual infectious diseases such as severe acute respiratory syndrome (SARS) or anthrax at an early stage. Whereas the usual surveillance systems are based on established diagnoses and emergency department discharge data, syndromic surveillance uses preliminary outcomes and derived data such as absenteeism, prescription medication and requests for laboratory tests. Investigations abroad have indicated the potential ofsyndromic surveillance. In the Netherlands, the National Institute of Public Health and Environment (RIVM) is examining the feasibility of implementing syndromic surveillance.

• Comparing pandemic to seasonal influenza mortality: Moderate impact overall but high mortality in young children

  C.C. van den Wijngaard, L. van Asten, M.P.G. Koopmans, W. van Pelt, N.J.D. Nagelkerke, C.C.H. Wielders, A. van Lier, W. van der Hoek, A. Meijer, G.A. Donker, F. Dijkstra, C. Harmsen, M.A.B. van der Sande, M. Kretzschmar

  PLoS ONE. 7(2).

  Cited By (since 1996): 1, Export Date: 25 April 2012, Source: Scopus, Art. No.: e31197

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• The burden of 2009 pandemic influenza A(H1N1) in the Netherlands

  C.C.H. Wielders, E.A. Van Lier, T.M. Van'T Klooster, A.B. Van Gageldonk-Lafeber, C.C. Van Den Wijngaard, J.A. Haagsma, G.A. Donker, A. Meijer, W. Van Der Hoek, A.K. Lugnér, M.E.E. Kretzschmar, M.A.B. Van Der Sande

  European Journal of Public Health. 22(1):150-157.

  Export Date: 25 April 2012, Source: Scopus

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• Unspecified gastroenteritis illness and deaths in the elderly associated with norovirus epidemics

  L. Van Asten, J. Siebenga, C. Van Den Wijngaard, R. Verheij, H. Van Vliet, M. Kretzschmar, H. Boshuizen, W. Van Pelt, M. Koopmans

  Epidemiology. 22(3):336-343.

  Cited By (since 1996): 3, Export Date: 25 April 2012, Source: Scopus

• Strengthening the diagnostic capacity to detect Bio Safety Level 3 organisms in unusual respiratory viral outbreaks

  L. van Asten, M. van der Lubben, C. van den Wijngaard, W van Pelt, R. Verheij, A. Jacobi, P. Overduin, A Meijer, D. Luijt, E. Claas, [......], C.A.B. Boucher, J Schirm, L. Kroes, S. Leenders, J.M.D. Galama, M Peeters, A M van Loon, E.E. Stobberingh, M Schutten, M Koopmans