A viral meningitis outbreak associated with Echo30 in drinking water / 中华流行病学杂志

ABSTRACT

Objective To study the source of infection,the scope of epidemic and control measures in an outbreak involving students having symptoms as fever,dizziness,headache,vomiting and nausea.Methods The suspected-case was defined as fever (armpit temperature ≥37 ℃) and with one or more of the following symptomsdizziness,headache,vomiting and nausea,among students and teachers at school from Mar 1,2012.Confirmed-case was among suspected case accompanied by both throat and rectal swabs enterovirus positive by RT-PCR.All the cases were collected through checking the medical records from 4 hospitals as well as through the absence records of students and teachers,from Mar 1,2012.We conducted a case-control study with ratio of 1 ∶ 2 and data on the exposures to water among students and teachers was collected prior to the illness.27 cases' throat and rectal swabs were collected and analyzed by RT-PCR and PCR sequence methods.2 warm-water samples were collected for testing the counts on total bacteria and E.coli.Results 103 students' cases were identified in school L,with the attack rate as 4.6％ (103/2255).Students from Grade three had the high attack rate as 18.1％ (72/397) and 77.7％ (80/103) of the cases located in the building with ' multiple-functions'.Epidemic curve of the outbreak showed a pattern with continuous common source of infection.It seemed that the exposure to warm-water appeared to be the major risk factor (OR =18.3,95％CI2.0-169.5) together with the intake of un-boiled water (OR =15.5,95 ％CI1.7-141.8).Specimens from 27 students (81.5％,22/27) were identified enterovirus positive by RT-PCR,and 7 of the 9 students were confirmed carrying Echo 30.Bacteria and coli were negative from the 2 warm-water samples.Conclusion This viral meningitis-outbreak was caused by Echo 30,with drinking water as the major risk factor.