Surveillance of neutralization antibody to Japanese encephalitis virus in healthy population in Tongchuan city, Shaanxi province

Objective To understand Japanese encephalitis virus (JEV) antibody level in the healthy population in Tongchuan, and provide scientific evidence for the prevention and control of Japanese encephalitis. Methods Totally 216 healthy people in 7 age groups (2, 3-5, 6-10, 11-15, 16-45, 46-60 and60 years old) were sampled by cluster random sampling in Yijun county of Tongchuan, and blood samples were taken from them to detect neutralization antibody (NA) to JEV by micro neutralization test. Results The positive rate of JEV NA (GMT) was 24.07% (1 ∶ 3.04) in the healthy population in Tongchuan. The positive rate (GMT) in age group 2 years old was highest (63.33%, 1 ∶ 11.06),the positive rates and GMT in other age groups ranged from 6.45% to 31.03% and from 1 ∶ 1.78 to 1 ∶ 3.95 respectively. The differences on antibody levels between different age groups were statistical significant. Conclusion The JEV antibody positive rate and GMT were relatively low in the healthy population in Tongchuan, which might facilitate the epidemic of Japanese encephalitis. It is necessary to strengthen the Japanese encephalitis vaccination to increase the vaccination coverage.