| [Background]Acute Meningitis/Encephalitis Syndrome (AMES) is a group of infectious diseases which mainly damages central nervous system, caused by infection of multi-biological pathogens such as bacteria, epiphyte, virus and so on. The usual pathogenic bacteria include Neisseria Meningitidis (NM), Streptococcus Pneumoniae (S.p), Haemophilus Influenzae Type b (HiB), etc. The usual pathogenic viruses include Japanese Encephalitis Virus (JEV), Human Enteroviruses (HEV), Herpes Simplex Virus (HSV Ⅰ and HSV Ⅱ), Varicella-zoster Virus (VZV), Cytomegalovirus (CMV), Mumps Virus (MuV), Rubella Virus (RV), etc[1]. AMES often occurs in the children under15years old, with high incidence of sequelae and serious harm. At the present, China has only brought epidemic cerebrospinal meningitis (ECM) and Japanese B encephalitis in AMES into national legal infectious diseases report system. The monitoring data about viral encephalitis and bacterial meningitis caused by other pathogens is still deficient. Previous analyses about these data were limited to clinical diagnosed cases. We are lack of reports about systemic epidemiological surveillance and analyses on epidemic characteristics of AMES as a syndrome in a certain area at a certain period. So from September of2006, supported by National CDC and Shandong Province CDC, our Ji Nan CDC established the first AMES surveillance system in China. We analyzed the epidemic characters of cases from AMES Sentinel Surveillance Hospitals and the test results of bacteria and viruses, in order to systematically understand the AMES’s regularty of epidemic and its composing of pathogens, to evaluate its incidence rate and occurrence features more accurately, and to protect children’s health by directing clinical treatment.[Objectives]1. To understand the incidence strength and the epidemic characteristics of different kinds of AMES.2. To analyze the composing of the pathogen spectrum and compare the difference between the bacterial encephalitis and viral encephalitis’clinical characteristics and inspection index.3. To provide reference of controlling and preventing AEMS for the disease control system.[Methods]The monitoring system of AMES was established in Ji’nan, which taking the clinical symptoms as the monitoring standards. Six sentinel surveillance hospitals from Ji’nan were selected, with2hospitals at provincial, prefectural and county level, respectively. The correlative data were collected for AMES cases from2007to2011. 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 the composition of viral meningitis/encephalitis or bacterial meningitis/encephalitis were analyzed according to the test results.The serum and CSF samples of AMES cases were collected, using the timely fluorescent PCR and blood and cerebrospinal fluid routine inspection results and clinical symptoms to determine whether it was the bacterial infection and what kind of bacteria it was. Enzymelinked immunosorbent assay (ELISA) was used for laboratory serological detection and diagnosis. Specific IgM antibodies to JEV, HEV, HSV, MuV, VZV, CMV and RV in serum specimens were examined. The pathogen constitute was analyzed, and the differences between bacterial encephalitis and virus encephalitis’clinical symptoms and the laboratory testing in conventional index were compared.The main statistic methods for analyzing data were Chisquare test, Fisher’s exact probability and Wilcoxon rank sum test, and the main index was constituent ratio.[Results]1. There were4131cases of AMES, reported by47hospitals above second class in ji’nan from2007to2011, among which2656cases were coming from ji’nan. The average annual incidence was8.46/100000people.2.2289AMES cases were reported by six sentinel surveillance hospitals, in which the proportion of ji’nan residents was47.96%. The male cases were1444, and female were845, so the sex ratio of male to female cases was1.71:1. Most cases were attacked by AMES from May to September, accounting for67.67%AMES cases of the whole year. Most of AMES cases were under15years old, which accounted for66.75%, and most of them were children who lived scattered, students and preschool children.3. Most of the sentinel surveillance hospitals’AMES cases were diagnosed as viral encephalitis, followed by the suppurative meningitis. Fever, vomiting, malaise, nausea and disorder of consciousness were the main clinical symptoms which occupied89.65%,55.05%,41.24%,38.18%,and19.79%of AMES cases, respectively. The clinical signs were mainly neck rigidity, meningismus and anterior fontanelle apophysis, occupied respectively22.37%,22.19%and16.75%of all the cases.4. CDC received1828AMES cases’serum and1515samples of cerebrospinal fluid. Seven kinds of virus’ IgM were detected by ELISA for all serum, and the positive rate respectively was HEV17.72%(324/1828), JEV9.57%(175/1828), HSV9.30%(170/1828), MuV9.08%(166/1828), VZV0.11%(2/1828), MV0.11%(2/1828), RV0.00%(0/1828). We test the IgM of meningitis b by ELISA on1515samples of cerebrospinal fluid and also three types of bacteria by RT-PCR detection, the positive rate was respectively JEV98.12%(123/1515), Nm1.06%(16/1515), Spl.52%(23/1515) and Hib0.00%(0/1515).5. Fever, headache, vomiting, listlessness were the main four clinical symptoms of viral infection among the confirmed cases, with the corporation of4.90%,62.42%,56.11%, and 42.42%, respectively. While the top four clinical symptoms of the bacterial infection were fever, listlessness, vomiting and headache, with the corporation of92.31%,66.67%,58.97%and58.97%, respectively. To compare the clinical manifestations of viruses and bacteria infections, there were significantly statistical significance on8clinical symptoms (nausea, sluggishness, drowsiness, convulsions, neck rigidity, opisthotonos, petechia and ecchymosis). In the inspection of the index, there were significant differences between the virus infection and bacterial infections on the white blood count, the white blood cells content in cerebrospinal fluid, the glucose levels of cerebrospinal fluid and the appearance of cerebrospinal fluid. However, there were no significant differences on the scale of the neutrophile granulocyte and the laboratory parameters of the chloride content in cerebrospinal fluid.6. Among the confirmed cases, virus infection ones mainly occurred from May to September, while there were some differences among different viruses. For example, the mumps mainly focused from April to July and the peak value happened in May. Intestinal virus cases mainly appeared from June to September and the peak value happened in July. Herpes simplex virus cases mainly concentrated from May to August and the peak value happened in July. Epidemic encephalitis B cases mainly appeared from May to early November and the peak value happened on September. There were only two chicken pox infection cases and all patients were in June, and the measles virus infection cases were two, all in January. As to the crowd distribution, the sex ratio (men/women) of intestinal virus, the single blister virus, the mumps virus and the epidemic encephalitis B virus infection were1.11:1,1.46:1,1.96:1and1.07:1, respectively, which indicated that the risk of infection to men was higher than women, while the men and women constituent ratio of the measles and the chicken pox were1:1(1/1). The infection age of all kinds of virus except for the measles were under ten years old, and the ratio of intestinal virus, the single blister virus, the mumps virus, the epidemic encephalitis B virus and chicken pox virus which infected under10years old children was86.46%(281/325),72.19%(122/169),78.31%(130/166) and100%(2/2), respectively. The two measles patients were adults. The professional distribution mainly concentrates in the children who lived scattered, students and preschool children.Among the bacterial infections, pneumoniae streptococcus infection could happen all the year and concentration trend was not apparent. The peak value of the Neisseria meningitidis infection was in May. The Age of the pneumoniae streptococcus infection mainly concentrated in under five years old (43.48%) and the aged (21.74%). The main epidemic meningitis cases were children under five years old (25.00%) and15-24years old teenagers(50.00%). It’s professional distribution mainly concentrates in the peasants, students and preschool children.7. In the hospitals, although AMES had clear pathogens, the misdiagnosis rate of epidemic meningitis and epidemic encephalitis B was50.72%and56.25%respectively with clear test results.[Conclusions]1. This study took the clinical symptoms as the basis for cases screening, and the morbidity of AMES in ji’nan was understood primarily through the cases reported in time by47hospitals above second class. By analyzing the AMES surveillance cases in six sentinel hospitals in Ji’nan, we found that there were some epidemic features and clinical characters in AMES cases.2. Through the testing of JEV HEV, MuV, HSV, VZV, RV, Nm, S.p and Hib in serum and cerebrospinal fluid of AMES cases by network laboratories, we found that MuV, HEV, HSV and JEV were the main pathogen of viral infection, and Nm and S.p were the main pathogen that caused bacterial infection. JEV and Nm is no longer the main pathogen causing encephalitis and meningitis.3. There were certain differences between the clinical manifestations and test results of cases caused by Viruses and by bacteria, and there were certain epidemiologic features in different pathogen infected cases.4. The misdiagnose of the AMES’pathogen was very serious. |
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