Study On Acute Meningitis, Encephalitis Syndrome Surveillance In Guigang City And On-site Assessment Of WHO Japanese Encephalitis Surveillance Standards

Acute encephalitis, meningitis are serious threat to human. Including encephalitis, meningitis, human infection with swine streptococcus disease and encephalitis-type hand foot and mouth disease is a major concern in recent years. China has no information on the incidence of such diseases as a whole; the current statutory surveillance of communicable diseases is also related to some defects. WHO published "JE Surveillance Manual" and "Bacterial Meningitis Surveillance Manual" in 2007, to be collected on-site application of information to support continued development of the manual.A bacterial meningitis and virus Encephalitis Joint surveillance was conduct in china firstly,1400 suspected cases were assessed, and more than 2000 CSF and serum samples were collected.In our study, mutli-pathogen diagnosis tests were carry out, Discriminant analysis and logistic regression were apply to data analysis. The Japanese Encephalitis Surveillance Standards was assessed by cohort study, some revisions were submitted to WHO expert committee.ChapterⅠStudy on Acute Meningitis, Encephalitis Syndrome Surveillance in Guigang City, GuangxiObjectives Apply WHO new surveillance standards to conduct acute meningitis, encephalitis syndrome surveillance for exploratory practice, describe disease burden and epidemiological characteristics of bacterial meningitis, Japanese encephalitis and other viral encephalitis, and provide the basis for the disease control strategy development.Methods Acute meningitis, encephalitis syndrome surveillance system was established in Guigang city. For the suspected cases, serum and CSF were collected,2-stage epidemiological investigation was conducted, and bacterial culture, latex agglutination test, real-time PCR and ELISA tests were carry out. All involved cases were identifying to 6 categories according to WHO case definition. Epidemiological characteristics and disease burden were described, for the purpose of risk factors analysis. Discriminant analysis and logistic regression were applied to find the Characteristic difference between bacterial meningitis and virus Encephalitis.Results 1424 suspected cases were evaluated in surveillance, Serum and/ or cerebrospinal fluid specimens in 1422 cases were collected. Laboratory testing results,98 serum and 85 CSF were positive for JE IgM ELISA test,239 serum were positive for other virus IgM ELISA test. Bacteria were culture out in 36 bloods and 34 CSF.1 copy of blood and 8 copy of CSF were positive for real-time PCR detection. For the 3 common meningitis pathogens, antibiotic resistance was observed in Nalidixic acid, Sulfamethoxazole and Ciprofloxacin. According WHO standards, there are 103,51,127,188,189 and 766 cases were confirmed for JE, bacterial meningitis, excluded cases, possible encephalitis, Clinical diagnosis of bacterial meningitis and suspected encephalitis, meningitis cases respectively, yield the Estimated annual incidence of 0.8209/100,000, 0.4065/100,000,3.7461/100,000,1.5064/100,000 for JE, bacterial meningitis, possible encephalitis, Clinical diagnosis of bacterial meningitis respectively. 95.15% of the JE and 50.00% of possible encephalitis cases was observed occurred in May, June and July, and 48.15% of the clinical diagnosis of bacterial meningitis cases was observed occurred in May, June, July and August. The highest incidence on 4 kinds of AMES was observed in Guiping city.96.10% JE cases were found in children under the age of 10, of which 73.80% of children under age of 5, bacterial meningitis cases have a distribution of ages. For JE cases, high frequencies of clinical manifestations are following:fever (98.10%), meningeal irritation sign (97.09%), convulsion (82.52%), consciousness change (77.67%) and fever (65.05%). In multi-factor analysis, "headache", "diarrhea", "bulging anterior fontanel", "blood white blood cell count" and "CSF glucose" etc 5 clinical indications have statistically significant difference between viral encephalitis and bacterial meningitis. "CSF glucose content," "headache," "Bulging anterior fontanel" and other six variables into the discriminant analysis model, "convulsions" has the biggest difference between the coefficients of discriminant function. According to the current legal infectious disease reporting system,65.05% Japanese encephalitis cases would be omitted in project site. A positive predictive value of 10.81% was observed in this syndrome surveillance system.Conclusions Our surveillance base on clinical manifestations rather than clinical diagnosis to capture suspected cases, equipped rapid mutli laboratory-confirmed test, combined with active surveillance-based as quality control measures, initially with a basic feature of syndrome surveillance system. Antibiotic resistance is Common for 3 major meningitis, vaccine is an important protective factor, JE vaccine immunization program shows the enormous effect in project site. This study show, the CSF has the high diagnostic value for pathogen confirm, bacteriological culture is still the preferred diagnostic method, antibiotic abuse is affecting factor of bacteriological detection. JE is one of the largest numbers of viral encephalitis; Coxsackie virus, ECHO virus and mumps virus are also important composition of viral encephalitis pathogen. Epidemic cerebrospinal meningitis is no longer the main component of bacterial meningitis, Cryptococcus neoformans and other conditions of bacterial meningitis pathogenic bacteria to become an important pathogen, Streptococcus Pneumonia, People infected with meningitis caused by Streptococcus Suis disease are relative multiple. Clinical diagnosis is not reliable, legal infectious diseases report system in China have further room for improvement. Syndrome surveillance is far higher than the national infectious disease reporting system in case capture ability, and captured the emerging infectious diseases in project site, is a necessary complement of traditional monitoring systems.Chapter II On-site Assessment of WHO Japanese Encephalitis Surveillance StandardsObjectives Assess the new edition of WHO Japanese Encephalitis Surveillance Standards base on syndrome surveillance data, to provide on-site evidence and suggestion for the improvement.Methods Base on syndrome surveillance data, categorize the AES case according to the new WHO standards. A cohort study was applied in study to estimate the AES definition in standard. The sensitivity, specificity, Youden index and the positive predictive value of AES components were calculated for the purpose of finding clinical significance with screening value. Discriminant analysis and logistic regression were applied to data analysis.Results 1424 suspected cases were reported in syndrome surveillance, and 1396 case with ELISA result, of which 109 positive cases were detected. According to "standards" classification, a total of 706 cases in line with AES case definition, was categorized into 83 cases of JE,425 cases of AES unknown and 198 cases of AES other agent. In cohort study, a relative risk of 4.62 (95% CI:2.80-7.63) and percentage of attributable risk of 78.35%(95%CI:64.25%-86.89%) were observed. The screening parameters are following:sensitivity 81%(95% confidence interval:79%-83%), specificity 53%(95% confidence interval:50%-55%), Youden index 0.33, kappa value of 0.10, positive and negative predictive values were 13% and 97%. In multi-factor analysis, the "fontanel uplift," "convulsions," "meningeal irritation" and so on seven variables entered the final model, the likelihood ratio statistic G= 144.07 (χ2=61.79, P=0.00). In discriminant analysis, the "fever", "disturbance of consciousness," "convulsions" and other six variables and eventually enter the model, with cross-validation rate of 75.18%.Conclusions AES definition for JE was statistically significant effects on the screening, there is strong correlation strength was observed in study, AES syndrome can cover most of the Japanese encephalitis cases. "Convulsions" with quite screening value, was recommended involved in the new version of the WHO standards. Classification in JE surveillance standards is not stringent enough in practical application, it is recommended to add classification of "bacterial meningitis" and "diagnosed with other diseases," two categories. The "seizure" is an important clinical screening indicator in field, "meningeal irritation," "Fever" and "appearance of CSF" and three clinical indications also has certain screening value. Discriminant analysis shows that, it's not reliable for diagnosis to JE base on routine clinical and laboratory examination, and only laboratory testing is sufficient basis for JE case report.