[Nosocomial epidemic outbreak of acute gastroenteritis by Norwalk-like virus].
BACKGROUND
From the notification of an acute gastroenteritis outbreak in a nursing home, an epidemiological study was started to determine the characteristics of the outbreak and its spreading pattern and to identify determining factors.


METHODS
A study of historic cohorts was performed and the case was defined by the presence of diarrhea and vomiting. Spatial aggregation in double rooms was analyzed by a binomial distribution and temporal aggregation was analyzed by a relative risks model. The variables in the study allowed us to calculate the adjusted relative risk; the odds ratio was calculated in relation to the meal on day January 30.


RESULTS
We studied 95.9% residents. The total attack rate was 28.7% (31.8% employees, 30.1% permanent residents and 15.2% day residents). The attack rate in rotation health personnel was 45.2%. Spatial and temporal spread in double rooms was negative. There was a significant association with the disease in rotator employees (RR = 3.22; CI 95%, 1.30-7.99; p = 0.02). No association was found between eating and disease (OR = 1.5; CI 95%, 0.4-6.1; p = 0.46). Norwalk-like virus was isolated in four faecal samples.


CONCLUSIONS
This epidemic outbreak had the characteristic of a nosocomial infection with a likely person-to-person transmission mechanism. The main factor contributing to the spread of the infection was the existence of employees in permanent contact with residents with an important physical and mental impairment, hence highly dependent on the care provided by these health workers.
González Morán
Francisco
F
Centro de Salud Pública de Castellón. Spain. francisco.gonzalez@sanidad.m400.gva.es
Moreno Civantos
Antonio
A
de Mateo Ontañón
Salvador
S
Barrasa Blanco
Alicia
A
Valadés Rodríguez
Javier
J
Domínguez Berjón
Felicitas
F
Herrera Guibert
Dionisio
D
Martínez Navarro
Ferran
F
D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D017250:Caliciviridae Infections / Q000453:epidemiology*; D015331:Cohort Studies; D003428:Cross Infection / Q000453:epidemiology*; D004196:Disease Outbreaks; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology*; D006801:Humans; D008297:Male; D029322:Norovirus; D013030:Spain