Data from the World Health Organization (WHO) National Network Laboratory for Japanese Encephalitis

AIM: Japanese encephalitis (JE) virus is the leading cause of viral neurologic disease and disability in Asia. In the present study JE virus-specific IgM in serum and CSF from acute encephalitis syndrome (AES) patients, attending Assam Medical College and Hospital (AMC and H), Dibrugarh, Assam from 2007 to 2009 were detected and different epidemiological parameters namely age, season and vaccination campaign were enumerated. MATERIALS AND METHODS: A cross-sectional study on patients with AES admitted in AMC and H, Dibrugarh, Assam was done during 2007 to 2009. The different epidemiological features were characterized depending on a pretested structured questionnaire called the clinical information form (CIF). Serum and CSF obtained were tested by a Panbio JE-Dengue IgM Combo ELISA kit and JEV Chex kit (Xycton). STATISTICAL ANALYSIS: A z-test was used for the statistical analytic assessment. RESULTS: Detection rate of JE was 39.4%, 51.1%, and 51.3% in the years 2007, 2008, and 2009 respectively. Cases of JE increased in the age group more than 15 years in the district where the vaccination program was undertaken. This increase of cases from pediatric to adults is also statistically significant by the z-test (P<0.05). CONCLUSION: There was an increase in AES cases and also JE cases from 2007 to 2009. JE also showed a seasonal variation with maximum cases in the months of July and August. Although vaccination campaigns with the live attenuated vaccine SA-14-14-2 have started and are protecting the under-15 children, there is a shift of disease pattern in the older population.