A Norovirus-associated Gastroenteritis Outbreak in a school in Yilan County, 2010

Ming-Chih Liu1,Dah-Shyong Jiang1,Yi-Ting Shen1,Wan-Ching Chen2,Hsuan-Chih Lin2,Wang-Chin Cheng3

2011 Vol.27 NO.20

Correspondence Author： Ming-Chih Liu

Abstract：

In September 2010, a gastroenteritis outbreak in School X was reported to Taiwan Centers for Diseases Control, involving 425 of the 2,199 students (attack rate = 20.1%). The most common symptoms were diarrhea (90.8%), abdominal pain (61.9%), and tenesmus (23.5%). Some patients had vomiting (8.9%). The average duration of illness was 4.3 days. Among those who had diarrhea, 72.9% had watery diarrhea and more than 60% had stool passage twice per day at least. Among those who had symptoms, 47.9% had sought medical consultation and 0.6% had been hospitalized. Stool specimens of 1 student and 2 restaurant workers were positive for norovirus but there was no pathogens detected in the water samples. Because of the two-peak appearance of the epidemic curve and the scattering of patients in different classes, the outbreak could be resulted from a combination of common-source exposure and human-to-human transmission. Risk factors could not be identified, but the number of patients ceased increasing after implementation of aggressive control measures. Norovirus is highly contagious in populous institutions and schools. A comprehensive surveillance and reporting system and early intervention might be helpful in controlling outbreaks, but environmental sanitation and hand hygiene are of fundamental importance.