Date Published:
Dec 18
Abstract:
An outbreak of acute gastroenteritis occurred in a nursing home
for elderly in Majorca between 4 and 23 February 2008. To know
its aetiology and mechanism of transmission a retrospective cohort
study was conducted with a fixed cohort including 146 people
(96 residents and 50 employees). The data were collected from
clinical histories and through a survey by questionnaire. In total 71
cases were identified (53 residents, 18 employees), corresponding
to an overall attack rate (AR) of 48.6%. The consumption of tap
water, adjusted by age, sex and consumption of meals provided at
the nursing home, presented a relative risk (RR) of 4.03 (95%CI,
1.4-11.4). The microbiological analyses confirmed the presence
of norovirus and/or rotavirus in five of the seven stool samples
submitted. The slow appearance of cases at the beginning of the
outbreak is characteristic of a person to person transmission, while
the sudden peak in the middle of the month suggests a common
source such as the tap water. We therefore concluded that the
outbreak likely originated from two sources: an infected employee of
the nursing home and the tap water. The high number of dependent
residents most probably facilitated the spread of the outbreak.
ECDC Europe Eurosurveillance