| r Background]Acute Meningitis/Encephalitis Syndrome (AMES) is a group of diseases with meningitis or encephalitis to be main clinical representations and characterized with rapid course of disease. AMES often occurs at the children under 15 year-old, and it is an important factor to the children's health. Many pathogens such as virus, bacterium, protozoon, and parasite can induce brain inflammation, with virus to be the mostly common pathogen, followed by bacterium, protozoon and parasite. Over 130 kinds of viruses can induce brain inflammation. Japanese B encephalitis virus (JEV), human enterovirus (HEV), herpes simplex virus type 1 and type 2 (HSV1, HSV2), varicella-zoster virus (VZV), cytomegalovirus (CMV), mumps virus (MuV) and rubella virus (RV) are the most common viral pathogens for AMES. Serological examination for antivirus IgM antibody in serum or CSF is one of the most commonly used method for diagnosis of virus infection at acute stage. AMES has a critical course of disease and a top rate of deformity and caused severe family and society burden. So, AMES is one of the most important public health problems.Since the occurrence of SARS in 2003, the prevention and control-especially the surveillance-of infectious diseases had been strengthened gradually in China. Some progress at the surveillance and laboratory test of fever and rash syndrome had been achieved, but researches on other syndromes were underway. At present, the majority of the epidemiological study on AMES in China, except the separate notifiable disease such as Japanese B Encephalitis (JE) and Meningococcal Meningitis, is the clinical data analysis. The research reports based on general and systemic AMES epidemic surveillance as a syndrome built at the hospital surveillance system to investigate its epidemic characteristics, were lacked.In this study, the epidemiology and viral serological diagnosis results of Shandong AMES sentinel surveillance cases were analyzed, so as to investigate the harm of the disease and to lay foundation for the institution of control strategies.[Objectives]1. To analyze the epidemic characteristics of AMES cases from sentinel hospitals in Jinan prefecture, and to explore the main risk factors.2. To investigate the pathogen spectrum and epidemiological characterization of AMES via serological examination.3. To analyze the diagnosable JE cases according to admitting clinical diagnosis by laboratory serum diagnosis, and know JE morbidity and the report of infectious disease, for providing the proof of JE control from now on.4. To summarize the experience of AMES surveillance and generalize the surveillance for the whole province or even the country, to improve the laboratory diagnosis ability to the major pathogens of AMES in Shandong province, and to enhance the surveillance and control of related diseases.[Methods]Six sentinel surveillance hospitals from Jinan city of Shandong province were selected, with 2 hospitals at provincial, prefectural and county level, respectively. The correlative data were collected for AMES cases in 2008 and 2009. The descriptive epidemiology was adopted as the main method to analyze the epidemic characteristics, and the primary epidemiological factors were discussed. The main clinical features and laboratory routine test indexes were analyzed, and they were classified by admitting clinical diagnosis. The clinical features included clinical syndrome and clinical sign, and the analysis item was constituent ratio. The laboratory routine test indexes were serum and CSF correlative indexes, and the differences between viral meningitis/encephalitis and bacterium meningitis/encephalitis were analyzed.The serum and CSF samples of AMES cases were collected and examined via serological method. Specific IgM antibodies to JEV, HEV, HSV, MuV, VZV, CMV and RV in serum specimens were examined via ELISA, and the CSF samples were examined by ELISA for the specific IgM antibody to JEV. The serum test results were analyzed, and the epidemiology characteristics of AMES whose specific IgM antibody to HEV, MuV and HSV was positive with higher proportions were analyzed too.Partial AMES cases were classified into JE clinical diagnosis group and missed diagnosis group, according to the JEV specific IgM antibody serology diagnosis results and the admitting clinical diagnosis of cases. The differences about the epidemic characteristics, clinical representations and clinical laboratory results of the two groups were compared.The main statistic methods for analyzing the data were chisquare test, Fisher's exact probability and Wilcoxon rank sum test, and the main index was constituent ratio.[Results]1.669 AMES cases were reported with 369 cases in 2008 and 330 cases in 2009. Seasonal peaks appeared from July to September for AMES cases in both years. The cases from Jinan residents were almost equal to those from non-Jinan residents. The ratio of male to female cases was 1.75:1. More than 70%AMES cases were children under 15 year-old, and the age median of onset was 7 year-old with most students, the day-care and preschool children.2. Febrile, headache, vomiting, nausea were the main four clinical symptoms of AMES cases, with the number of 653(93.42%),422(60.37%),409(58.51%) and 297(42.49%), respectively. The number of cases with neck rigidity and meningismus was relatively more with 155(22.17%) and 129(18.45%) cases. In the aspect of the laboratory routine test indexes, the differences of WBC count, the percentage of neutrophils, the content of the protein in CSF, the content of WBC in CSF, the content of glucose in CSF and the content of chloride in CSF between viral meningitis/encephalitis and bacterium meningitis/encephalitis were statistically significant. In admitting clinical diagnoses,574 AMES cases (82.12%) belonged to virus infection and 73 cases (10.44%) belonged to bacterium infection.3.95.93%(354/369) and 99.09%(327/330) of serum and/or CSF samples were collected from the reported AMES cases in 2008 and 2009. The specific IgM antibody to JEV was examined for all samples, and the positive rate was 10.28%(70/681 cases). The positive results on the specific IgM antibody to other six kinds of viruses from other serum samples of 480 cases were 17.29%(83/480 cases) for MuV,16.88% (81/480 cases) for HEV,10.63%(51/480 cases) for HSV,3.33%(16/480 cases) for RV,2.92%(14/480 cases) for RV, and 1.88%(9/480 cases) for CMV.4. The differences of gender distribution and region distribution in epidemiology characteristics between JE clinical diagnosis group and JE missed diagnosis group were not statistically significant. The proportion of the cases under five years old in the missed diagnosis group was higher. The differences of age distribution between the two groups were statistically significant (X2=:3.99, P<0.05). The seasonal distribution showed a peak from July to September in both clinical diagnosis group and missed diagnosis group. In the aspect of clinical representations such as depressed mind, conscious disturbance and neck rigidity, the number of cases in clinical diagnosis group was distinctly higher compared with missed diagnosis group, and the differences were statistically significant(P<0.05). The differences were not statistically significant between the two groups in other clinical symptom and sign. In the aspect of laboratory routine test index, there was more CSF leucocyte content in missed diagnosis group compared with clinical diagnosis group, and the differences were statistically significant (Wilcoxon rank sum test, P<0.05). There were no statistic significances between the two groups in other indexes.[Conclusions]1. By analyzing on the AMES surveillance in six sentinel hospitals in Jinan, we found, firstly, there were some epidemic features and clinical characters in AMES cases; secondly, the viral infection was the main aspect in the admitting diagnosis; lastly, AMES was the syndrome which could be seen frequently in the clinic. More surveillance and controlling work should be reinforced for AMES cases in the future.2. It could be found that MuV, HEV, HSV and JEV were the main pathogens of AMES cases in the aspect of viral infection of the six sentinel hospitals in Jinan city of Shandong province by examination on virus specific IgM antibody in serum or CSF samples via ELISA. The surveillance of AMES cases should be reinforced from now on, especially the pathogen diagnosis in the laboratory.3. JE is the disease which can be prevented by vaccine. After the JE vaccine was brought into Expanded Program on Immunization of children in 1986 in Shandong province, the morbidity had decreased year after year. It appeared that the general control measure which was taken consistent in inoculating JE vaccine in Shandong province had acquired great achievements. However, by serological examination, it could be found that some JE cases were missed diagnosis for slight symptoms or the absence of laboratory pathogen diagnosis. Hence in the future, JE surveillance and reporting should be reinforced, and the examination of the JEV specific IgM antibody in serum or CSF specimens should be paid great attention to in the JE diagnosis.4. After the establishment of National Notifiable Disease Reporting System in 1951, there were not comprehensive and systemic data of AMES cases which were caused by the other viruses except the JE and Meningococcal Meningitis which were brought into the routine surveillance. Reinforcing the surveillance and laboratory diagnosis of AMES cases could make for the guidance of therapy and improve the survival rate. The surveillance and prevention of AMES cases should be reinforced from now on. |
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