From January 2004 through December 2006, 110 acute encephalitis cases were reported; 75 (68.2%) were confirmed as JE via positive JEV IgM ELISA test in their CSFs, and 50 JE cases belonged to the 2004 cohorts aged 1-9 year(s) whose incidence rates were 11.32, 2.15, and 2.79 per 100,000 in Group A, B and C districts respectively in 2004 (Table 1) and were 5.22, 7.51, and 9.75 per 100,000 respectively in 2005; the rates declined significantly in all 3 groups in 2006. The gene discussed is CD40LG; the disease is Japanese encephalitis.