Burden of gastroenteritis outbreaks: specific epidemiology in a cohort of institutions caring for dependent people

BACKGROUND:In institutions caring for dependent people, viral gastroenteritis occurs frequently and is highly contagious. In elderly persons, these episodes can lead to hospitalization and occasionally death. AIM:To study the impact of gastroenteritis outbreaks (GOs) in institutions caring for dependent people. METHODS:This study was conducted on 18 sites consisting of 35 units from four different disciplines (geriatric medicine and rehabilitation, psychogeriatrics, geriatric nursing homes, and specialized care homes for adults with physical and mental disabilities). Spatio-temporal analysis of GOs was performed during six winter seasons, and clinical and viral data were analysed with regard to structural parameters (size of the sites and dining-room organization), virus epidemiology and chronology of the outbreaks and type of activities. RESULTS:A total of 98 outbreaks were recorded in the 35 units. The risk of GO was high even outside national epidemic periods. Viruses were searched for in 86 outbreaks and were identified in 96.5% (83/86) of these outbreaks: norovirus genotype GII.4 (59.0%, 49/83), other viruses (41.0%, 34/83). There were variations between surveillance periods in terms of GO frequencies and attack rates and types of viruses. Dining-room organization could be a factor in cross-infection at a site. CONCLUSION:Specific surveillance that takes into account the precise epidemiology needs to be developed in institutions caring for dependent people in order to improve infectious disease control and information for healthcare workers.