Analysis of integrated virological and epidemiological reports of norovirus outbreaks collected within the Foodborne Viruses in Europe network from 1 July 2001 to 30 June 2006.

The Foodborne Viruses in Europe network has developed integrated epidemiological and virological outbreak reporting with aggregation and sharing of data through a joint database. We analyzed data from reported outbreaks of norovirus (NoV)-caused gastroenteritis from 13 European countries (July 2001 to July 2006) for trends in time and indications of different epidemiology of genotypes and variants. Of the 13 countries participating in this surveillance network, 11 were capable of collecting integrated epidemiological and virological surveillance data and 10 countries reported outbreaks throughout the entire period. Large differences in the numbers and rates of reported outbreaks per country were observed, reflecting the differences in the focus and coverage of national surveillance systems. GII.4 strains predominated throughout the 5-year surveillance period, but the proportion of outbreaks associated with GII.4 rose remarkably during years in which NoV activity was particularly high. Spring and summer peaks indicated the emergence of genetically distinct variants within GII.4 across Europe and were followed by increased NoV activity during the 2002-2003 and 2004-2005 winter seasons. GII.4 viruses predominated in health care settings and in person-to-person transmission. The consecutive emergence of new GII.4 variants is highly indicative of immune-driven selection. Their predominance in health care settings suggests properties that facilitate transmission in settings with a high concentration of people such as higher virus loads in excreta or a higher incidence of vomiting. Understanding the mechanisms driving the changes in epidemiology and clinical impact of these rapidly evolving RNA viruses is essential to design effective intervention and prevention measures.

Data quality of 5 years of central norovirus outbreak reporting in the European Network for food-borne viruses.

BACKGROUND: The food-borne viruses in Europe (FBVE) network database was established in 1999 to monitor trends in outbreaks of gastroenteritis due to noroviruses (NoVs), to identify major transmission routes of NoV infections within and between participating countries and to detect diffuse international food-borne outbreaks. METHODS: We reviewed the total of 9430 NoV outbreak reports from 13 countries with date of onset between 1 January 2002 and 1 January 2007 for representativeness, completeness and timeliness against these objectives. RESULTS: Rates of reporting ranged from a yearly average of 1.8 in 2003 to 11.6 in 2006. Completeness of reporting of an agreed minimum dataset improved over the years, both for epidemiological and virological data. For the 10 countries that provided integrated (epidemiological AND virological) reporting over the 5-year period, the completeness of the minimum dataset rose from 15% in 2003 to 48% in 2006. Two countries have not been able to combine both data types due to the structure of the national surveillance system (England and Wales and Germany). Timeliness of reporting (median days between the onset of an outbreak and the date of reporting to the FBVE database) differed greatly between countries, but gradually improved to 47 days in 2006. CONCLUSION: The outbreaks reported to the FBVE reflect the lack of standardization of surveillance systems across Europe, making direct comparison of data between countries difficult. However, trends in reported outbreaks per country, distribution of NoV genotypes, and detection of diffuse international outbreaks were used as background data in acute questions about NoV illness and the changing genotype distribution during the 5-year period, shown to be of added value. Integrated reporting is essential for these objectives, but could be limited to sentinel countries with surveillance systems that allow this integration. For successful intervention in case of diffuse international outbreaks, completeness and timeliness of reporting would need to be improved and expanded to countries that presently do not participate.

Comparison of the European Union Disease Surveillance Networks' websites.

Currently the surveillance of infectious disease in the European Union (EU) is supported by the Basic Surveillance Network (BSN) and other disease specific surveillance networks (DSNs). Each network has its own website. The objective of the current study was to describe the information presented with public access on each website from the perspective of its usefulness for the surveillance of an EU member state. The BSN and the DSNs cited in Decision 2003/542/CE were included. Each website was reviewed and assessed on the inclusion of characteristics from three broad categories: 1) general information, 2) procedures for data collection and 3) data presentation. Ten surveillance network websites were reviewed during the week of 5 December 2005. At least 80% of the 10 networks included a list of participating countries, the contact addresses for the coordinator of the network and the participating country gatekeepers and the network's objectives. Only one network specified the source and coverage of the data of each country on its website, and seven presented the disease case definition. Raw data were shown on eight websites and only two networks included presentation of elaborated data for the whole of the EU. Four networks included no reports on their websites. The periodicity of presentation for both raw data and elaborated data varied greatly between networks. The publicly available information on the 10 network websites studied was not homogeneous. We recommend that all networks present a basic set of characteristics on their websites, including case definitions, procedures used for data collection and periodic reports covering elaborated data for the entire EU.

Waterborne outbreak among Spanish tourists in a holiday resort in the Dominican Republic, August 2002.

On 3 September 2002, the Spanish national centre of epidemiology (Centro Nacional de Epidemiologia--CNE) was alerted to a high number of gastroenteritis cases in Spanish tourists who had travelled to a hotel in Punta Cana on different days during august 2002. Entamoeba hystolitica cysts have been visualised by microscopy in the stools of several patients that sought medical attention in the Dominican Republic. The CNE informed the health authorities in the Dominican Republic and conducted in conjunction an epidemiological investigation. A descriptive study of the 76 initial cases estimated a mean illness duration of 5.1+2.9 days and a exposure period of 3.6+2.2 days. Following a retrospective cohort study, the attack rate was found to be 32.4%. Consequently, 216 (95% CI=114.75-317.25) spanish tourists had probably developed the illness. Stool samples were collected in Spain from untreated patients who still felt unwell. None of the samples were positive for E.hystolitica. On 10 September, a hygiene inspection was undertaken at the hotel. Samples of the ice and meals served at the buffet that day, yielded coliform bacteria. Consumption of water from the resort water system was the only risk factor associated with the symptoms (RR= 3.55; 95% CI =1.13-10.99). To avoid similar outbreaks occurring again at the hotel, it is essential to regularly monitor the water quality and to improve food handling hygiene standards. Basic food hygiene training for food handlers should be mandatory. An international guideline for the management foodborne and waterborne outbreaks among tourists in holiday resorts should be drawn up, involving all competent authorities of both destination and tourist origin countries.