[Norovirus outbreaks in hospitals and nursing homes in Catalonia, Spain].
BACKGROUND
The low infectious dose and multiple transmission routes favour the appearance of norovirus outbreaks. The objective of this study was to compare the incidence of norovirus outbreaks in hospitals and nursing homes in Catalonia.


METHODS
A descriptive study of norovirus outbreaks between 15/10/2004 and 30/10/2005 was carried out. An epidemiological survey was completed for each outbreak. Norovirus in clinical samples was determined by PCR techniques. The incidence in each centre and the annual incidence of outbreaks by centre were calculated. Differences were calculated using the chi-square test and the Student's t test, taking a p value of > 0.05 as significant.


RESULTS
Seventeen outbreaks (6 in hospitals and 11 in nursing homes) were detected. The global attack rate was 33.4% (652/1951) and was slightly higher in nursing homes (35.2%) than in hospitals (31.4%). A total of 94.1% (16/17) of outbreaks were caused by person-to-person transmission and only 5.9% (1/17) by foods. The mean number of days between the first and last case was 11.4 (SD = 6.9). The mean duration of symptoms was 2.39 days (SD=1.6), and was higher hospitals, 2.63 (SD=1.7), than in nursing homes, 1.97 (SD=1.7) (p < 0.0001).


CONCLUSIONS
Norovirus is responsible for a large number of outbreaks due to person-to-person transmission. Control should be standardized to reduce the number and duration of outbreaks.
Godoy
Pere
P
Departamento de Salud, Generalidad de Cataluña, Barcelona, España. pere.godoy@gencat.net
Domínguez
Angela
A
Alvarez
Josep
J
Camps
Neus
N
Barrabeig
Irene
I
Bartolomé
Rosa
R
Sala
María Rosa
MR
Ferre
Dolors
D
Pañella
Helena
H
Torres
Joan
J
Minguell
Sofía
S
Alsedà
Miquel
M
Pumares
Analía
A
D000368:Aged; D017250:Caliciviridae Infections / Q000453:epidemiology*; D003428:Cross Infection / Q000453:epidemiology*; D004196:Disease Outbreaks; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology*; D006761:Hospitals; D006801:Humans; D015994:Incidence; D008297:Male; D029322:Norovirus; D009735:Nursing Homes; D013030:Spain / Q000453:epidemiology