-
[show abstract]
[hide abstract]
ABSTRACT: SUMMARYShiga toxin-producing Escherichia coli (STEC) bacteria can cause outbreaks and sporadic cases of gastroenteritis in humans. Ruminants are seen as the main reservoir. The aim of this study was to evaluate the spatial association between reported human STEC O157 infections in The Netherlands and different livestock densities. Data were collected at the municipality level and a spatial regression analysis was performed. Between April 1999 and December 2008, 409 symptomatic sporadic cases were registered. Adding an interaction term between season, age, and livestock density showed an increased risk of STEC cases in summer for living in areas with cattle, in particular for young children. In conclusion, cattle, but not pigs or poultry, are indicated as an important source for human STEC O157 infections in rural areas. The association is probably due to direct or indirect contact with cattle, resulting in symptomatic infections, especially in young children.
Epidemiology and Infection 09/2010; · 2.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In healthcare settings, norovirus (NoV) outbreaks are predominated by genotype II.4 (GII.4) strains. Periodically, new variants of GII.4 emerge, causing a temporary increase of outbreaks.
To study the relationship between symptoms and NoV genotype.
Data of 49 nursing homes which were monitored for NoV outbreaks in the winter seasons of 2005/2006 and/or 2006/2007 were used.
Data on symptoms and duration of illness were available for 465 residents and 174 staff members from 28 NoV outbreaks. Genotype GII.4 was responsible for 21 outbreaks. Attack rates for residents seemed to be higher in GII.4 outbreaks compared to other genotypes. In outbreaks caused by GII.4, residents vomited more often than in outbreaks with other genotypes. They also had more often complaints of nausea, abdominal cramps, fever, and mucus in stool. The GII.4 2004 variant outbreaks showed higher percentages of nausea, stomach ache, and fever than outbreaks with the GII.4 2006a variant. Differences in duration of illness were not found. In nursing home staff, no clear differences were found between outbreaks caused by GII.4 and non-GII.4 NoVs.
Genotype GII.4 was found to be related to more symptomatic disease, including more residents vomiting, and to a lesser extent, higher attack rates among residents.
Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology 09/2009; 46(4):341-4. · 3.12 Impact Factor
-
I H M Friesema,
H Vennema,
J C M Heijne, C M de Jager,
G Morroy,
J H T C van den Kerkhof,
E J M de Coster,
B A Wolters,
H L G ter Waarbeek,
E B Fanoy,
P F M Teunis,
R van der Linde,
Y T H P van Duynhoven
[show abstract]
[hide abstract]
ABSTRACT: Effective infection control measures during norovirus outbreaks are urgently needed in places where vulnerable individuals gather. In the present study, the effect of a number of measures was investigated in daily practice. Forty-nine Dutch nursing homes were monitored prospectively for norovirus outbreaks during two winter seasons. A total of 37 norovirus outbreaks were registered. Control measures were most effective when implemented within 3 days after onset of disease of the first patient. Measures targeted at reduced transmission between persons, via aerosols, and via contaminated surfaces reduced illness in staff and in residents. Reducing illness in staff results in fewer costs for sick leave and substitution of staff and less disruption in the care of residents. The effect of control measures on outbreak duration was limited. This is the first intervention study examining the effect of control measures. Further research is needed to extend and refine the conclusions.
Epidemiology and Infection 06/2009; 137(12):1722-33. · 2.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In September 2005, the first national food-related outbreak of Shiga toxin (Stx)-producing Escherichia coli (STEC) O157 was investigated in the Netherlands. A total of 21 laboratory-confirmed cases (including one secondary case), and another 11 probable cases (two primary and nine secondary cases) were reported in patients who became ill between 11 September and 10 October 2005. Preliminary investigation suggested consumption of a raw beef product, steak tartare (in the Netherlands also known as "filet americain"), and contact with other symptomatic persons as possible risk factors. A subsequent case-control study supported the hypothesis that steak tartare was the source of the outbreak (matched odds ratio (OR) 272, 95% confidence interval (CI) 3-23,211). Consumption of ready-to-eat vegetables was also associated with STEC O157 infection (matched OR 24, 95% CI 1.1-528), but was considered a less likely source, as only 40% of the cases were exposed. Samples of steak tartare collected from one chain of supermarkets where it is likely that most patients (67%) bought steak tartare, all tested negative for STEC O157. However, sampling was done three days after the date of symptom onset of the last reported case. Since 88% of the cases became ill within a two week period, point source contamination may explain these negative results. It is concluded that steak tartare was the most likely cause of the first national food-related outbreak of STEC O157 in the Netherlands.
Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 08/2006; 11(7):182-5. · 6.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In order to add to the limited data available about the incidence of invasive Listeria monocytogenes infection in the Netherlands, two studies were conducted. In the first study, data on hospital patients with listeriosis in the period 1995-2003 were obtained from the National Medical Registration (study 1). In the second study, hospital discharge letters for patients whose Listeria isolates were received by the Netherlands Reference Laboratory for Bacterial Meningitis (NRLBM) in the period 1999-2003 were retrieved (study 2). Serotyping and pulsed-field gel electrophoresis (PFGE) were used to subtype the various strains of Listeria. These reviews revealed 283 hospital patients and 159 patients with Listeria isolates. Discharge letters were received for 107 (67%) patients. The mean annual incidence of listeriosis in both studies was 2.0 per million inhabitants. The main clinical manifestations were meningitis (incidence: 0.9 and 1.0 per million in studies 1 and 2, respectively) and septicaemia (incidence: 0.08 and 1.0 per million, respectively). Listeriosis in pregnancy was rare (incidence: 1.3 and 2.4 per 100,000 pregnancies over 24 weeks of gestation, respectively). Predisposing conditions were present in 47 and 71% of the patients in studies 1 and 2, respectively. The mortality due to listeriosis was 18%. Serotypes 4b, 1/2a, and 1/2b were responsible for 96% of the cases of human listeriosis. Listeriosis is rare in the Netherlands, but its clinical course is severe and the resulting mortality is high. Therefore, the current recommendations for pregnant women to avoid high-risk foods should be continued. These dietary recommendations should also be given to individuals with predisposing conditions, since they, too, are at risk of Listeria infection.
European Journal of Clinical Microbiology 08/2006; 25(7):433-42. · 2.86 Impact Factor
-
Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 02/2006; 11(4):E060420.4. · 6.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: An outbreak of highly pathogenic avian influenza A virus subtype H7N7 began in poultry farms in the Netherlands in 2003. Virus infection was detected by RT-PCR in 86 poultry workers and three household contacts of PCR-positive poultry workers, mainly associated with conjunctivitis. To determine the magnitude of and risk factors for human-to-human transmission of influenza A/H7N7 in the Netherlands, a retrospective cohort study among household members of infected poultry workers was undertaken. In total, 33 (58.9%) of 56 (among 62) participants who provided blood samples had positive H7 serology, using single convalescent serum samples obtained at least 3 weeks after onset of symptoms of the index case. Eight household members (12.9%) reported symptoms (conjunctivitis and/or ILI), of which four of five (80.0%) tested seropositive. On univariate analysis, significant risk factors for seropositivity included having at least two toilets, a pet bird, and using cloth handkerchiefs. It was not possible to obtain a stable model for binomial regression for the outcome of A/H7N7 infection. Further seroprevalence studies among contacts of asymptomatic H7 cases should be conducted.
Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 01/2006; 10(12):264-8. · 6.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In 2002, in The Netherlands a national study of gastroenteritis outbreaks was performed. Epidemiological information was collected by the Public Health Services (PHS) and the Food Inspection Services (FIS) using standardized questionnaires. Stool samples were collected for diagnostic testing. For foodborne outbreaks, food samples were taken. In total, 281 gastroenteritis outbreaks were included, mainly from nursing homes and homes for the elderly (57%), restaurants (11%), hospitals (9%) and day-care centres (7%). Direct person-to-person spread was the predominant transmission route in all settings (overall 78%), except for restaurant outbreaks where food was suspected in almost 90% (overall in 21% of outbreaks). The most common pathogen was norovirus (54%), followed by Salmonella spp. (4%), rotavirus group A (2%), Campylobacter spp. (1%) and only incidentally others. In conclusion, most outbreaks were reported from health and residential institutions, with norovirus as the dominant agent. Control should aim at reducing person-to-person spread. In foodborne outbreaks norovirus was common, due to contamination of food by food handlers. Salmonella, as the second foodborne pathogen, was mainly associated with raw shell eggs. These results stress the continuous need for food safety education, complementary to governmental regulation.
Epidemiology and Infection 03/2005; 133(1):9-21. · 2.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In 2002, in The Netherlands a national study of gastroenteritis outbreaks was performed. Epidemiological information was collected by the Public Health Services (PHS) and the Food Inspection Services (FIS) using standardized questionnaires. Stool samples were collected for diagnostic testing. For foodborne outbreaks, food samples were taken. In total, 281 gastroenteritis outbreaks were included, mainly from nursing homes and homes for the elderly (57%), restaurants (11%), hospitals (9%) and day-care centres (7%). Direct person-to-person spread was the predominant transmission route in all settings (overall 78%), except for restaurant outbreaks where food was suspected in almost 90% (overall in 21% of outbreaks). The most common pathogen was norovirus (54%), followed by Salmonella spp. (4%), rotavirus group A (2%), Campylobacter spp. (1%) and only incidentally others. In conclusion, most outbreaks were reported from health and residential institutions, with norovirus as the dominant agent. Control should aim at reducing person-to-person spread. In foodborne outbreaks norovirus was common, due to contamination of food by food handlers. Salmonella, as the second foodborne pathogen, was mainly associated with raw shell eggs. These results stress the continuous need for food safety education, complementary to governmental regulation.
Epidemiology and Infection 01/2005; 133(01):9 - 21. · 2.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The aim of this study was to analyse the results of a programme in the Netherlands for enhanced surveillance of Shiga-toxin-producing Escherichia coli (STEC) O157. In this programme, implemented in January 1999, all laboratories report positive cases to the public health services and submit isolates for typing to the reference laboratory. Public health services collect clinical and risk factor information of patients, using a standardised questionnaire. Results were analysed for the first two and a half years of the programme. In February 2000, a questionnaire was sent to all laboratories to assess (i) the criteria for testing faecal samples for STEC O157, (ii) the diagnostic tools used, and (iii) the level of participation in the surveillance programme. Between January 1999 and June 2001, 93 cases of symptomatic STEC O157 infection were reported, 25% of which occurred in children aged 0-4 years. Serotyping for O, H and stx types showed that two types dominated, O157:H7, s tx2 positive (48%) and O157:H-, stx1 and stx2 positive (24%). Analysis of the 93 isolates by pulsed-field gel electrophoresis showed 17 clusters of isolates with at least 95% fragments in common, including isolates with unknown epidemiological links. Of the patients for whom questionnaire information was reported, 38% were hospitalised, 15% developed haemolytic uraemic syndrome, and 52% reported a known risk factor, such as contact with farm animals or manure, consumption of raw or undercooked beef, consumption of raw milk or cheese made from raw milk, or contact with a symptomatic individual. Response to the laboratory survey was high (97%). Only 6% of the laboratories carried out testing for non-O157 STEC, although 95% performed testing for STEC O157. The majority (88%) used culture on sorbitol MacConkey agar or sorbitol MacConkey agar with cefixime and tellurite as the method of detection of STEC O157. The identity of the strains was confirmed primarily with commercially available latex agglutination assays (95% of laboratories) and biochemical characterisation with the API 20E test (bioMérieux, France) (42% of laboratories). Most laboratories (92%) used selection criteria for testing, especially bloody diarrhoea and other clinical information (81% of laboratories) and young age (10%). It is concluded that STEC O157 is a limited public health problem in the Netherlands, although the selective testing policy and the low sensitivity of the culture techniques used probably caused the incidence of STEC O157 infection to be underestimated.
European Journal of Clinical Microbiology 08/2002; 21(7):513-22. · 2.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In September 2005, the first national food-related outbreak of Shiga toxin (Stx)-producing Escherichia coli (STEC) O157 was investigated in the Netherlands. A total of 21 laboratory-confirmed cases (including one secondary case), and another 11 probable cases (two primary and nine secondary cases) were reported in patients who became ill between 11 September and 10 October 2005. Preliminary investigation suggested consumption of a raw beef product, steak tartare (in the Netherlands also known as 'filet americain'), and contact with other symptomatic persons as possible risk factors. A subsequent case-control study supported the hypothesis that steak tartare was the source of the outbreak (matched odds ratio (OR) 272, 95% confidence interval (CI) 3 - 23211). Consumption of ready-to-eat vegetables was also associated with STEC O157 infection (matched OR 24, 95% CI 1.1 - 528), but was considered a less likely source, as only 40% of the cases were exposed. Samples of steak tartare collected from one chain of supermarkets where it is likely that most patients (67%) bought steak tartare, all tested negative for STEC O157. However, sampling was done three days after the date of symptom onset of the last reported case. Since 88% of the cases became ill within a two week period, point source contamination may explain these negative results. It is concluded that steak tartare was the most likely cause of the first national food-related outbreak of STEC O157 in the Netherlands.
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
