[Outbreak of foodborne disease by Norwalk-like viruses genogroup II].
BACKGROUND
Our goal was to investigate the epidemiological characteristics and etiology of an outbreak of food-borne disease caused by Norwalk-like viruses, genogroup II.


METHODS
We performed a historical cohort study on the consumption of 21 food items and clinical symptoms. We assessed RNA Norwalk-like viruses by RT- PCR in stool samples from 5 patients and 2 food-handlers. The potential involvement of each food item was assessed by relative risk at 95% confidence intervals (CI).


RESULTS
The overall attack rate was 70.0% (7/10). The median incubation period was 35.0 hours. Symptoms included: vomits 85.7% (6/7), fever 85.7% (6/7) and diarrhoea 71.4% (5/7). Four food items were involved [fish (RR = 1.7; CI 95% 0.9-3.3); 'selection of cold meats' (RR = 1.6; CI 95% 0.9-2.7); yoghurt (RR = 1.5; CI 95% 1.0-2.4) and lamb (RR = 1.3; CI 95% 0.6-3.0)]. Three stool sample gave positive results for Norwalk-like viruses genogroup II. Important oversights in food-handlers' work were detected.


CONCLUSIONS
RT-PCR enabled us to confirm the etiology of this outbreak as Norwalk-like viruses genogroup II. Although patients recovered quickly, the outbreak caused considerable public alarm.
Godoy
Pere
P
Facultad de Medicina, Universidad de Lleida, Spain. godoy@slle.scs.es
Prat
Alba
A
Alsedà
Miquel
M
Torres
Joan
J
Domínguez
Angela
A
Salleras
Lluís
L
D001906:Botulism / Q000453:epidemiology* / Q000821:virology*; D017250:Caliciviridae Infections / Q000150:complications* / Q000235:genetics; D004196:Disease Outbreaks; D005759:Gastroenteritis / Q000150:complications* / Q000235:genetics; D005838:Genotype; D006801:Humans; D029322:Norovirus / Q000302:isolation & purification*; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013030:Spain / Q000453:epidemiology
D012367:RNA, Viral
Toxiinfección alimentaria por virus Norwalk-like genogrupo II.