Etiological structure of acute encephalitis in children and immunization program concerns at The National Hospital of PaediatricS in Vietnam.

37 Encephalitis is defined by the presence of an inflammatory process of the brain in association with clinical evidence of neurologic dysfunction. Among the pathogens that are reported to cause encephalitis, the majority are viruses. There are many benefits for the management of encephalitis if the cause is identified. However, despite extensive testing, the etiology of encephalitis remains unknown for the majority of patients. There are several causes of encephalitis that are now considered to be vaccine-preventable, that is, Japanese encephalitis (JE), measles, mumps, polio, rubella, and varicella. Other causes of encephalitis may include autoimmune disease; bacteria, such as Lyme disease, syphilis, and tuberculosis; and parasites, such as roundworms, and cysticercosis. In Vietnam, JE remains the most common cause of encephalitis. This is also one of the common etiologic pathogen of encephalitis in many ASEAN countries, as well as in India and China (Tuan et al, 2007; Sunara and Touch, nd). Our study’s research questions included: 1) what is the current etiological structure of viral encephalitis in Vietnamese children, and how has it changed over time?; and 2) has the national vaccination program reduced the number of children developing encephalitis in Vietnam? The objectives of the study were to compare the etiological structure of viral encephalitis in children at the National Hospital of Paediatrics, Hanoi, Vietnam in 2012 to the period of 2008-2012 and to analyze the National Immunization Program statistic data of Vietnam (MOH, 2008). The diagnostic criteria used were based on the “Guidelines for diagnosis and treatment of acute viral encephalitis” delivered by the Vietnamese Ministry of Health in 2008 and the guidelines of the Infectious Diseases Society of America (IDSA) (Tuan et al, 2007; IDSA, 2008). The etiology of the encephalitis was confirmed by the results of immunological and biomolecular tests on cerebrospinal fluid (CSF) and serum samples, such as polymerase chain reaction (PCR) and enzyme-linked Immunosorbent assay (ELISA) techniques. During 2012, there were 565 cases admitted to the NHP with the diagnosis of “acute encephalitis.” The causative agents were identified in only 147 patients (26%). The causative agents were JE virus 40.8%, herpes simplex virus 31.9%, enterovirus 14.3%, cytomegalovirus 4.8%, Epstein barr virus 4.8%, and mumps 3.4%. The incidence of JE was found to peak during the summer months of June to September ETIOLOGICAL STRUCTURE OF ACUTE ENCEPHALITIS IN CHILDREN AND IMMUNIZATION PROGRAM CONCERNS AT THE NATIONAL HOSPITAL OF PAEDIATRICS IN VIETNAM