Surveillance of viral encephalitis in some areas of Henan province

Objective To analyze pathogen species and prevalent characteristics of the viral encephalitis in some areas of Henan province. Methods Surveillance data on all viral encephalitis(VE)cases diagnosed in 2008 were collected from Xinxiang,Kaifeng,and Luoyang.The blood and cerebrospinal fluid(CSF)samples were collected from the cases and IgM antibody against Japanese encephalitis(JE)was detected with enzyme-linked immunosorbent assay(ELISA).The antibody of other virus was detected with reverse transciption-PCR(RT-PCR).Cell culture separation was conducted for IgM antibody negative specimens. Results A total of 215 viral encephalitis cases were reported and 47(21.86%)cases were positive for IgM antibody against JE.A total of 24(14.29%)intestinal virus strains were isolated from the cerebrospinal fluid of 168 IgM antibody negative cases.Among the the virus,there were twelve of ECHO30,seven of ECHO6, four of ECHO25,and one of CoxB5.The 47 JE and 168 intestinal virus and other viral encephalitis cases occurred mainly in July to September,accounting for 93.62% and 70.24% of the cases.The 0-14 years old group of JE and intestinal virus and other virus encephalitis cases occurred mainly in Xinxiang(91.91% and 92.31%)and Kaifeng(97.92% and 98.41%).The 0-14 years old cases of intestinal virus and other viral encephalitis cases accounted for 92.99% of all cases in Luoyang city and≥15 years old cases of JE significantly increased(56.52%).The incidences of JE,intestinal virus,and other viral encephalitis were significantly different between 0-14 years old group and≥15 years old group (χ²=21.13,P<0.05).The JE cases were mainly farmers in Luoyang and the JE cases of intestinal virus and other viral encephalitis in Xinxiang and Kaifeng were mostly scattered children,children in and kindergarten,or students. Conclusion Japanese encephalitis virus and intestinal virus are main pathogens of viral encephalitis in Xinxiang, Kaifeng,and Luoyang.The peak season of the intestinal virus and other viral encephalitis was the same as that of JE.The age and occupation distribution of the cases are different in different areas.