Eurosurveillance - Volume 9, Issue 3, 01 March 2004

Improvements in public health and the control of communicable diseases throughout Europe have been achieved due to the multidisciplinary approach and not only as a result of efforts of public health physicians. The conclusions of the Spanish team that studied the outbreak of gastroenteritis in tourists visiting the Dominican Republic provides a good example of the need for both cross discipline and international cooperation. Tourism is one of the top three global economic forces, with an increasing number of tourists each year. It is estimated that there are over 70 million package holidays sold in Europe annually with destinations worldwide. The tourists are exposed to a wide range of conditions and pathogenic organisms.

On 3 September 2002, the Spanish national centre of epidemiology (Centro Nacional de Epidemiología - 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.

In October 2001, foodborne outbreaks (FBO) were included in the Portuguese alert and response surveillance system. Accordingly, the northern regional health authority (Delegado Regional de Saúde do Norte - DRSN) began a surveillance programme of foodborne outbreaks. This report is a brief description of data generated from this programme in 2002. For each foodborne outbreak the local health authority (Delegado de Saúde Concelhio - DSC) produced a written report. Fifty-nine percent of the 27 FBOs studied by DSCs during 2002 were reported within 72 hours after the date of onset. Five hundred and seventy seven people became ill, 9.6% of the patients were admitted to hospital, and no deaths were reported. The aetiological agent was identified from patients in 63% of FBOs, and in food items in 18.5% of the situations. Salmonella enterica was responsible for 73.7% of the outbreaks in which the agent was laboratory confirmed. Meals implicated in the outbreak were mainly prepared in restaurants and private homes (75.0% of FBO). Inadequate processing, preparing or handling of foods were the contributing factors more often reported by the DSC. We believe that epidemiological surveillance and control of FBO must be reinforced in Portugal as part of a wider strategy to promote food safety.

In January 2003, the Institut de Veille Sanitaire received notification of clusters of gastroenteritis (GE) thought to be associated with consumption of oysters harvested from Etang de Thau in the south of France. At the same time Italy reported an outbreak (200+ cases) associated with oysters from the Etang de Thau. An investigation was carried out to determine the source and vehicle of the outbreaks. Descriptive analysis of reported clusters in France, microbiological analysis of stool and oyster samples, genotyping of noroviruses and an environmental investigation of the Etang de Thau were carried out. A retrospective cohort study was also undertaken among those attending a number of family meals in Paris. Thirteen family clusters in four districts of France (69 cases) could be attributed to the consumption of Thau oysters based on descriptive evidence. Oysters distributed at an office in Paris and consumed at fourteen family meals between 19 and 24 December led to a further outbreak. In this outbreak the attack rate was 21/36 (58%) for Thau oyster consumers and 0/22 for non-consumers (p=0.00002). Noroviruses (genogroups I and II) were found in stool samples from four clusters and oysters from three clusters (including Paris). Environmental investigations revealed heavy rainfall, an overflow of a water purification station and faecal contamination of the Etang de Thau in December. Oysters from the Etang de Thau were responsible for a number of clusters of norovirus GE in winter 2002 in France and also in Italy. High Escherichia Coli levels in Thau water and shellfish led to an official request, mid-December, for oyster purification before distribution. This was not possible, due to lack of purification facilities. This investigation has contributed to a change in the way that shellfish harvesting areas are classified in France.

This work describes and analyses an outbreak of epidemic keratoconjunctivitis which occurred in 2001 and 2002 in a nursing home for the elderly in Leganes (an area of Madrid). This is the first such published case in Spain with these characteristics and this serotype identification. Sociodemographic characteristics, epidemic curve and attack rates are described. Comparisons of the data were carried out using a chi2 test for qualitative variable and t-test for quantitative. Factors associated with the illness are explored by means of contingency tables and logistic regression models. One hundred and two cases were detected, with an attack rate of 36.4% for residents, and 12.9% for workers, not considering spatial or professional differences. The epidemic curve showed an interpersonal transmission pattern. Multivariate analysis identified the following risk factors in the residents: able to wander freely through the building, urinary incontinence and use of shared bathroom. In 34.6% of the conjunctival samples, adenovirus serotype 8 was detected with identical genomic sequence. Establishment of hygienic sanitary guidance adapted for the cleaning of such establishments and contact with residents as well as early diagnosis and good coordination of human and material resources are key factors in the prevention and control of these outbreaks in closed communities.