Noroviruses represent an important cause of gastroenteritis outbreaks, in particular those related to closed or semi-closed communities such as hospitals, cruise ships and hotels [1–4]. A possible gastroenteritis outbreak in a hotel located in northern Majorca was reported on 23 June 2009. The subsequent investigation revealed a total of 14 cases with onset of symptoms from 18 June to 24 June. Norovirus was thought to be the pathogen responsible for the outbreak.
A case was defined as any guest or employee of the hotel with acute onset of at least two of the following symptoms: diarrhoea, vomiting, abdominal clumps or fever (>37°C). Cases were identified through the symptoms and epidemiological questionnaires provided by the medical staff attending the hotel. A total of 685 guests were resident in the hotel during the outbreak, and ten cases were identified among them: five adults (four women and one man), four children between 2 and 14 years old and one baby (<2 years old). The attack rates were 1.06%, 2.4% and 2.0%, respectively. Guests were attended by 90 employees, four of them (all women) being affected. In this case, the attack rate was 4.4%. However, when data only from the entertainment team were analysed, the attack rate increased to 66.7%, rising to 100% for those working directly in the children’s club of the hotel. The most frequent symptoms were vomiting (93%), diarrhoea (50%), abdominal pain (29%) and fever (7%). The duration of symptoms ranged from 1 to 4 days. Two children and one woman were hospitalized for hydration support, with good outcomes. Fig. 1 shows the evolution of cases, with an initial peak on 18 June and all the remaining cases between 21 June and 24 June. Initially, three members of the same family were affected, with one vomiting episode being described at the children’s club. A few days later, new cases appeared among guests and staff members.
Figure 1. Evolution of cases, by date of onset of symptoms, for an outbreak of gastroenteritis in a hotel in Majorca, June 2009 (n = 14).
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Both clinical and environmental samples were analysed to determine the aetiological agent of the outbreak. Four stool samples from four patients were taken for culture during the acute phase of the gastroenteritis. Samples were analysed for intestinal pathogens, including Salmonella, Shigella, Yersinia, Cryptosporidium and norovirus. One sample from a child was also tested for rotavirus and adenovirus. Genotype 2 norovirus was detected in two of the four samples, one from an adult and one from a child, with the IDEIA Norovirus ELISA kit (DakoCytomation, Ely, UK). All other pathogens tested negative.
Environmental samples were tested on 23 June. Food samples were analysed for total aerobic count, enterobacteria, Escherichia coli and other lactose-fermenting Enterobacteriaceae, Staphylococcus aureus, Salmonella and Listeria. Drinking water was tested for total aerobic count, E. coli and other coliforms, and Clostridium perfringens. Ice cubes were analysed for E. coli and other coliforms. Pool water samples were analysed for E. coli and other coliforms, S. aureus and Pseudomonas aeruginosa. Levels of microorganisms were acceptable in all cases, ruling out their role as a source of infection.
As for the control procedures, once the gastroenteritis problem was spotted, a specially designed plan to solve the problem was rapidly implemented. Enhanced hand hygiene practices were established, and cleaning and disinfection of frequently contacted surfaces (doorknobs, phone keys, etc.) with 70% alcohol was performed. Common areas, especially toilets, were also frequently treated with bleach. Special care was taken in the children’s club and patients’ rooms. General guidelines included the following: the use of vapour for carpets and curtains and mopping for floor-cleaning instead of brooms and vacuum cleaners, to avoid air dissemination of norovirus; a long washing machine programme for virus inactivation in possibly contaminated clothes; and the use of masks, gloves and closed bags when dealing with vomit.
Several cases of norovirus outbreaks have been described in hotels worldwide. However, to our knowledge, they have been described only in hospitals [5,6] and the community [7,8] in Spain. In Majorca, only one norovirus outbreak in a nursing home for the elderly has been reported .
In this article, we describe a gastroenteritis outbreak caused by norovirus in a hotel. Stool sample analysis demonstrated that genotype 2 norovirus, the most prevalent in recent years , was present in 50% of the tested samples, and no additional pathogen was detected. These results demonstrate that norovirus was the aetiological agent of the outbreak.
Epidemiology data showed that all guest cases were children and members of their family, mainly their mothers. The affected staff were in direct contact with children, and some of the employees even worked at the children’s club. In fact, all of the employees belonging to this last group presented gastroenteritis symptoms. A vomiting episode was described at the beginning of the outbreak in the children’s club, and was probably the main source of infection. Airborne and environmental transmission of norovirus after vomiting episodes is well established in hotel outbreaks [11–14]. The most probable scenario is that one member of the family affected by gastroenteritis symptoms on 18 June acquired the infection outside the hotel and infected members of their family through close contact, and that the rest of the patients became ill after acquiring norovirus at the children’s club, or indirectly from these people. Person-to-person transmission is frequently associated with norovirus outbreaks [13,15]. In some cases, food and food-handlers or drinking water play a role in norovirus transmission [13,16–18]. Recreational water has also been involved in gastroenteritis outbreaks . However, in our case, an origin within the hotel is improbable because: (i) analysis of environmental samples showed that food, drinking water and recreational water met the sanitary standards; and (ii) the number of cases would have been higher and more diverse. The characteristics of the affected people clearly indicate that the children’s club was directly or indirectly involved in all cases.
In summary, the present investigation describes a gastroenteritis outbreak caused by norovirus, associated with a hotel children’s club. This case reflects the importance of a rapid analysis and response to control the outbreaks caused by norovirus in hotels, avoiding extreme measures such as closure because of the outbreak becoming out of control (Doménech-Sánchez A, 3rd Congress of European Microbiologists, FEMS, 2009, Abstract 3008).