Analysis of an outbreak of GⅡ norovirus in a middle school in Ninghe District, Tianjin City
LIU Jie1, CONG Longxue2
1.Ninghe District Center for Disease Control and Prevention, Tianjin 301500, China; 2.Ninghe District Center for Disease Control and Prevention, Tianjin 301500, China
Abstract:Objective To investigate and analyze the epidemiological characteristics of an outbreak of acute gastroenteritis caused by norovirus (NV) in a middle school in Ninghe District, Tianjin City, in order to provide scientific evidence and experience for the treatment of similar epidemics in the future. Methods According to the “Diagnostic Criteria for Infectious Diarrhea” and the “Technical Guidelines for Norovirus Infection Outbreak, Prevention and Control”, the on-site investigation was carried out, the descriptive epidemiological method was used for data analysis, and relevant specimens were collected, and the NV nucleic acid detection was performed by real-time fluorescent quantitative PCR. Results From November 12 to 17, 2019, there were a total of 41 confirmed cases of NA infection, including 38 students with a prevalence rate of 3.02% (38/1 260) and 3 faculty and staff with a prevalence rate of 1.22% (3/245), with no significant difference (χ2=2.484, P=0.115). There were 420 students in all grades, and the case incidence rates were 4.76% (20/420) in grade 1,2.62% (11/420) in grade 2, and 1.67% (7/420) in grade 3, respectively, with a statistically significant difference (χ2=7.218, P=0.027). The prevalence rates of day students and residential students were 0.68% (3/439) and 4.26% (35/821), respectively, and the difference was statistically significant (χ2=12.532, P<0.001). A total of 95 samples of feces, vomit and swabs were collected for NV nucleic acid testing, of which 59 were detected with NV-GII, with a positive rate of 62.10% (59/95). The positive detection rates of feces, swabs and vomit samples were 80.00%, 46.67%, and 72.00%, respectively, and the difference was statistically significant (χ2=10.138, P=0.006). Conclusions The outbreak was caused by NV-GII, which was clustered by grade, and the positive detection rate of norovirus in fecal specimens was higher than that of other specimens. After taking measures such as case isolation, diagnosis and treatment, sanitation and disinfection, the epidemic situation has been effectively controlled. Therefore, when dealing with the epidemic, it is necessary to strengthen the investigation of transmission route and the source of infection, and the nucleic acid testing of the virus, so as to identify and properly handle the epidemic in a timely manner and control the spread of the epidemic.
刘杰,丛龙学. 天津市宁河区某中学1起GⅡ型诺如病毒暴发疫情分析[J]. 中国校医, 2023, 37(12): 905-907.
LIU Jie, CONG Longxue. Analysis of an outbreak of GⅡ norovirus in a middle school in Ninghe District, Tianjin City. Chinese Journal of School Doctor, 2023, 37(12): 905-907.