Etiological Test And Epidemic Analysis For Samples Of Viral Encephalitis In Some Areas Of Hebei Province

Objective:1 To study the pathogenic and epidemic characteristics of viral encephalitis in Hebei Province, to provide scientific evidence for monitoring and prevention and control of viral encephalitis.2 To investigate viral encephalitis caused by the Getah virus in Hebei area.Methods:1 Collection and transcription of samples: According to the clinical standardizations of viral encephalitis serum and cerebrospinal fluid samples of patients or suspects were collected at acute stage. Most of the samples were from monitoring site hospitals and some samples were from non-monitoring site hospitals. All the samples were transported frozen to the laboratory for examination and stored at -70℃to preserve;2 Enzyme-linked immunosorbent assays were used for detection of IgM antibody to Japanese encephalitis virus, Enteroviruses, Herpes simplex virus, Epstein-Barr virus, Cytomegalovirus, Varicella-zoster virus, Rubella virus and Mumps virus. The RNA of Getah virus was detected by polymerase chain reaction from 100 patients of Serum or cerebrospinal fluid specimens;3 On the basis of the Japanese encephalitis data of our province which reported over the years and reference the documents of this topic the tendency and the cause of the Japanese encephalitis of our province was analyzed. The purpose is to provide scientific evidence for prevention and cure measure of Japanese encephalitis and ensure the people's healthy much better.Results:1 We collect 431 samples of 384 cases from various monitoring hospitals include 220 samples of serum and 211 samples of cerebrospinal fluid. 323(77.5%) samples focus on May to October videlicet summer and fall seasons. The ages of patients are between 29 days and 79 years of age. Among these cases the number of people that smaller than 15 years of age is 288(82.1%). The number of male is 243 and female is 136. Male female ratio is 1.8:1.2 Japanese encephalitis virus IgM antibodies are detected in 28 of 384 cases. The positive ratio is 7.3%. We pick 193 serum samples of 189 cases from 356 cases which are negative in JEV IgM antibody for detection of other viruses because the kit is not applicable for cerebrospinal fluid samples. Among 189 cases, 104 cases are positive. The positive ratio is 55.0%. The most common pathogen is enteroviruses (43, 22.8%), followed by herpes simplex virus (23, 12.2%), mumps virus (18, 9.5%), varicella-zoster virus (12, 6.3%), Epstein-Barr virus (5, 2.6%), cytomegalovirus (2, 1.1%), Rubella virus (1, 0.5%).We statistics all the positive cases by areas. The results show that enteroviruses take a large percentage of viral encephalitis cases in Shijiazhuang, and then the secondary pathogen is herpes simplex virus. While mumps virus takes a large percentage of viral encephalitis cases in Handan.3 100 patients were tested negative in Getah virus by PCR.4 With the apply of the Japanese encephalitis vaccine in wide scale, the incidence of Japanese encephalitis descends notably. Since 2000 the incidence depress 0.1/10 thousand, Hebei province becomes one of the lowest incidence province nationwide. The whole epidemic situation of Japanese encephalitis takes a descent tendency over ten years. The incidence is to change with the season, above 80% cases are concentrated in 7 to 10 month. But the other month has the sporadic cases. The patients are distributed over 11 cities of the whole province, but focus on the countryside region of Cangzhou, Handan, Xingtai and Hengshui while Zhangjiakou and Chengde that are situated northwest of Hebei province have fewer cases. The patients are mainly students, farmer and children. 57.2% cases are under 15 years old. The ratio of male and female is 1.5:1. Conclusion:1 According to the study, children and teenagers are subject to virus encephalitis and boys are more liable to it than girls; the peak of incidence occurred in summer and autumn; Herpes simplex virus, Enterovirus and Mumps virus are important pathogens in Hebei province.2 Although we have succeed in separating Getah virus from mosquito specimen, it has not definite that Getah virus could cause human encephalitis.3 The incidence of Japanese encephalitis has depressed below 0.1/10 thousand since 2000 in Hebei province. It becomes one of the lowest incidence province nationwide. Over the years the number of Japanese encephalitis cases that reported and died cases descends gradually except a small peak in 2006(0.108/10 thousand) but the whole epidemic situation of Japanese encephalitis takes a descent tendency.4 The distribution of pathogens in different areas of Hebei province shows different characteristic. We must aim at different characteristic of distribution of pathogens in different areas to take measures to prevent and control viral encephalitis.