• Bestrijding van aviaire influenza onder pluimvee: vaccinatie als aanvullende mogelijkheid

      Aarle, P van; Breytenbach, J; Schueller, S (RIVM, 2006-08-01)
      Since mid-December 2003, highly pathogenic avian influenza (HPAI) has caused an epidemic in the Asian poultry sector and avian influenza cases have been reported in Europe, the Middle East and Africa. Human fatalities catapulted avian influenza into the public arena with fears of a possible global influenza pandemic in case the virus gains capacity to spread from human to human. What should be the way forward? The article describes control options and discusses the role vaccination can play in combating specifically under European conditions and in dynamic poultry markets in other countries.
    • Epidemiologische trends in cryptokokkose : De Cryptococcus gattii-uitbraak in Canada

      Hagen, F; Boekhout, T (RIVM, 2006-06-01)
      Cryptococcosis is, when untreated, a fatal disease, which in the Netherlands is mainly caused by the basidiomycetous yeast Cryptococcus neoformans, and in more rare cases by Cryptococcus gattii. Infections with C. gattii occur almost only in immunocompetent individuals, while C. neoformans has a predilection for immunodeficient humans. Another major epidemiological difference between both species is the restriction of C. gattii to tropical and sub-tropical regions, whereas C. neoformans can be found worldwide. However, the distribution pattern of C. gattii has dramatically changed by an ongoing outbreak in the temperate climate of Vancouver Island (British Columbia, Canada). Epidemiological research revealed that the outbreak is caused by the rare AFLP genotype 6 (= VGII) of C. gattii. Only a few strains of this genotype were known before this outbreak. Since the past decade, however, strains of this genotype are isolated more frequently, especially in South America. In the Netherlands, the number of infections with C. neoformans in HIV/AIDS patients shows a decreasing trend, due to the introduction of the HAART therapy. However, clinicians and microbiologists should also be alert for infections caused by C. gattii in (immunocompetent) individuals who travelled recently to Vancouver Island and the main land of British Columbia (Canada).
    • Filet américain oorzaak van eerste landelijke uitbraak van Shigatoxine-producerende Escherichia coli O157-infecties

      Doorduyn, Y; Jager, C M de; Zwaluw, W K van der; Friesema, I H M; Heuvelink, A E; Boer, E de; Wannet, Wim J B; Duynhoven, Yvonne T H P van (RIVM, 2006-08-01)
      In September 2005, the first nationwide outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 infections was observed. A total of 21 confirmed and 11 probable patients were reported, who fell ill between September 11 and October 10. Preliminary investigation by the local public health services revealed two possible risk factors: consumption of steak tartare and contact with other persons with gastroenteritis. The results of the subsequent case-control study suggested steak tartare as the most likely cause of the outbreak. Samples of steak tartare taken at a supermarket chain where most of the patients bought the product, tested negative for STEC O157. However, sampling took place 3 days after the date of symptom onset of the last outbreak case. Because 88% of the cases became ill within a two-week period and samples taken shortly afterwards tested negative, point source contamination of steak tartare was considered most plausible.
    • Geen paniek! : Zelfredzaamheid bij uitbraken van infectieziekten

      Helsloot, I (RIVM, 2006-09-01)
      The understanding of citizen response to disaster is crucial to outbreak management of infectious diseases. Large scale outbreaks cannot be mitigated without the active corporation of citizens. This article shows that citizens in general will not panic, are not helpless and will not start plundering. Inappropriate actions and communication of authorities may cause unwanted reactions of citizen which then are labelled by both authorities and media as panic or irrational behaviour.
    • Intensieve surveillance van Shigatoxine-producerende Escherichia coli O157 in Nederland, 2005

      Friesema, I H M; Jager, C M de; Heuvelink, A E; Zwaluw, W K van der; Maas, Henny M E; Pelt, W van; Wannet, Wim J B; Duynhoven, Yvonne T H P van (RIVM, 2006-08-01)
      Since January 1999, an enhanced surveillance of Shiga toxin-producing Escherichia coli (STEC) O157 has been implemented in the Netherlands. In 2005, 53 symptomatic patients were diagnosed with STEC O157. This was relatively high compared with the number in previous years (annually 36 to 57), due to a national outbreak with 21 patients involved. Of the patients, 33% were hospitalised, 8% developed the haemolytic-uraemic syndrome (exclusion of outbreak-cases: 13%), including one one-year-old boy who died. Consumption of raw or undercooked beef and contact with farm animals and manure are still most frequently mentioned by the patients as possible cause. In 2005, cluster analyses of the fingerprints of bacterial DNA from the STEC O157 isolates (by pulsed-field gel electrophoresis) nine times suggested a relationship between several patients. For three clusters this was supported by additional epidemiological information. One cluster, consisting of two sub clusters, comprises the national outbreak caused by filet américain, except for two patients who fell ill two and one month before this outbreak. Furthermore, one household cluster was identified for which an indistinguishable PFGE pattern was found in a manure isolate taken from their cattle. In addition, an isolate from one individual case could be matched with an isolate taken from their neighbours cattle. As other serogroups than O157 can cause serious illness, a collaboration between RIVM and eight medical microbiological laboratories to assess the relative importance of non-O157 serogroups was started in the Netherlands in the autumn of 2005.
    • Malariameldingen in 2005: Evaluatie van de richtlijnen van het Landelijk Coördinatiecentrum Reizigersadvisering (LCR) voor malariaprofylaxe

      Sondera, G J B; Plas, Simone M van der (RIVM, 2006-08-01)
      In The Netherlands, malaria is a notifiable disease in group C since 1999: the laboratory where the patient tested positive has to report the test results, together with a few demographic data, to the National Center for Disease Control (CIb). Since January 2005, the National Coordination Center for Travelers Health Advice (LCR) added some questions to the voluntary part of these reports in order to obtain more insight in the prevalence of malaria in people who used prophylaxis according to the LCR guidelines, and to evaluate these guidelines. The goal of the LCR guidelines is to prevent malaria caused by P. falciparum. All reported cases with a disease onset date in 2005 were evaluated. In 2005, 288 cases of malaria were reported. Seventy-five (26%) malaria patients used chemoprophylaxis. In total, 32 (11%) contracted malaria despite the use of chemoprophylaxis according to the LCR guidelines. Eight of these cases concerned malaria caused by P. falciparum. Four of these had used second choice chemoprophylaxis, to which parasitic resistance is common. In the blood sample of one patient no mefloquine was detected. Of the other three, the thick smear or EDTA blood was not available for resistance tests. Most likely, all other cases had a delayed onset malaria, which cannot be prevented by the currently available chemoprophylaxis. Based on these data, we conclude that the LCR guidelines are still valid. It is advised that in cases of breakthrough malaria caused by P. falciparum blood samples are taken to determine chloroquine or mefloquine levels where applicable, and to save EDTA blood for molecular confirmation of the species and determination of resistant parasites.
    • Praktijkevaluatie van de regionale toepassing van artikel 7 van de Infectieziektenwet

      Petrignani, M W F; Yap, K B (RIVM, 2006-08-01)
      In 1999 a new Dutch law on notifiable diseases is implemented. It contains article 7, which states that institutions are obliged to report unusual numbers of inhabitants or staff with symptoms of infectious diseases to the local public health service. We think evaluation of the actions deriving from article 7 is in place. We analysed regional data from these reports in the years 2003, 2004 and 2005. Thereby categorizing medical and non-medical institutions. Most of the reports come from non-medical institutions and can be dealt with by giving information and advice. Skin infections and rashes were reported the most. Medical institutions often reported actual outbreaks. 41% Of all institutions in our region contacted us in the period that was analyzed. We conclude that our role is well known to the regional institutions and that we have a good idea of how they report. Because of the large diversity in registration of article 7 reports, national surveillance is not useful. Registration of certain reports might attribute to surveillance of specific syndromes. A more uniform registration can attribute to an improvement in the quality of local public health services.
    • Rubella-epidemie 2004-2005: surveillance van congenitale gevolgen

      Veen, Y van der; Hahné, Susan J M; Ruijs, H; Timen, A; Binnendijk, R S van; Loon, T van; Melker, Hester E de (RIVM, 2006-09-01)
      In 2004-2005, the Netherlands experienced an outbreak of rubella. The Centre for Infectious Disease Control (CIb/RIVM) monitors characteristics and the extent of the outbreak and reports on the disease-burden of rubella, congenital rubella-virus infection (CRI) and congenital rubella syndrome (CRS). In this article, the used methods for surveillance and the results are presented and discussed. Data available so far, indicate that 32 pregnant women were infected during the outbreak, resulting in 15 cases of CRI. Nine of these infants showed symptoms associated with CRS. Surveillance of the congenital consequences of the rubella-epidemic is a difficult task, but important for effective treatment, increasing of the knowledgebase and immunization and antenatal screening policy
    • Vaccinaties in het eerste levensjaar en gerapporteerde allergische aandoeningen bij kinderen van 8-12 jaar

      Bernsen, R M D; Jongste, Johan C de; Koes, B W; Aardoom, H A; Wouden, J C van der (RIVM, 2006-06-01)
      Evidence for the relationship between the diphtheria tetanus pertussis (DTP) vaccination and allergic disorders is inconclusive, because the available studies that constitute the evidence are liable to confounding by indication. Further the Haemophilus influenzae type b (Hib) vaccination was added recently to most existing vaccination programmes and therefore no conclusive data on the relationship with allergic disorders are yet available. Objective of the study was to assess the relationship between vaccinations in the first year of life and reported allergic disorders at primary school age. We conducted a cross sectional study in 1875 children attending Orthodox Reformed (Protestant) primary schools in the Netherlands. The parents returned questionnaires with data on vaccination status, allergic symptoms and lifetime allergic disorders (asthma, hay fever, eczema and food allergy), and possible confounders. In the diphtheria tetanus pertussis (inactivated) poliomyelitis (DTP-IPV) vaccinated group Hib vaccinated and Hib unvaccinated children were compared as to allergic disorders. No clinically or statistically significant differences in the prevalence of asthma, hay fever, eczema and food allergy appeared between vaccinated and unvaccinated groups. The DTP-IPV vaccination and the Hib-vaccination, administered in the first year of life, do not increase the risk of allergic disorders in 8-12 years-old, Dutch children.