[Quality of case report of Japanese Encephalitis after the establishment of surveillance on acute meningitis and encephalitis syndrome in Baoji].

Objective: To evaluate the quality of Japanese Encephalitis (JE) case reports based on the establishment of surveillance on acute meningitis and encephalitis syndrome (AMES) in Baoji. Methods: A surveillance network on AMES cases was set up in Baoji city of Shaanxi province between July 2013 and December 2016. All the cases met the surveillance definition of AMES cases were conducted a questionnaire, collected serum and/or cerebrospinal fluid (CSF) specimens to test JE immunoglobulin M antibodies by using enzyme-linkedimmunosorbent assay methods.The information of the incidence of JE in Shaanxi and Baoji from 2009 to 2016 originated from the China information system for disease control and prevention. Chi square test was used to compare the difference in JE incidence in Baoji, Shaanxi before and after the implementation of AMES monitoring project. Results: 75 out of 855 collected cases were laboratory confirmed as JE, Including 42 suspected JE cases and 33 other suspected cases diagnosed after hospitalization. Except 1 case occurring in December, all the other cases occurred between July and October, especially in August with a peak of 55 cases (73.3%), and 6 cases (8.0%) in July, 11 cases (14.7%) in September, 2 cases (2.7%) in October. The proportion of patients aging 0-6, 7-14 and ≥15 years old were respectively 4.0% (3 cases), 8.0% (6 cases) and 88.0% (66 cases). The biochemical test showed the cerebrospinal fluid in 13 cases (17.3%) were slightly turbid, the white blood cell in 31 cases (41.3%) elevated, the glucose levels in 24 cases (32.0%) were abnormal, and the chloride level in 23 cases (30.7%) were abnormal. A total of 103 cases of JE were diagnosed in Baoji from 2009 to 2016, with an average annual incidence rate at 0.34/100 000. The average incidence of JE in 2009-2012 and 2013-2016 was 0.21/100 000 and 0.48/100 000 respectively. From 2013 to 2016, the proportion of JE cases in Baoji, Shaanxi was 19.3% (71/369), and it was 8.9% (32/362) between 2009 and 2012 (χ(2)=4.15, P=0.040). Conclusion: The AMES surveillance project improved the quality of the JE case report in Baoji. Changes appeared in biochemistrical and epidemiological characteristics of cerebrospinal fluid. The incidence of JE was seriously underestimated in Shaanxi province and therefore the sensitivity of Japanese encephalitis surveillance cases should be further improved.