[A viral meningitis outbreak associated with Echo30 in drinking water].

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°C) and with one or more of the following symptoms: dizziness, 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%CI: 2.0 - 169.5) together with the intake of un-boiled water (OR = 15.5, 95%CI: 1.7 - 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.