Last updated on 02 December 2025

Main points

  • DEMELE-JEV is a prospective observational paediatric cohort, combining both cross-sectional and longitudinal designs, conducted in Cambodia.
  • The primary aim of the study is to quantify the clinical burden of Japanese Encephalitis (JE) and to investigate the asymptomatic circulation of JEV among Cambodian children.
  • The study focuses on two groups: children without fever at recruitment and children hospitalized with febrile neurological syndrome (FNS).

Objectives of the ANRS 0629s DEMELE-JEV study

Primary endpoint

Incidence of Japanese Encephalitis Virus infection in both participant groups based on laboratory confirmation (PCR positivity, seroconversion, or 4 fold antibody rising based on ELISA results, with confirmatory testing by virus neutralization assays).

Secondary endpoints

  • To estimate the anti-JEV seropositivity rate in children attending Kantha Bopha hospitals in Phnom Penh and Siem Reap for different age groups.
  •  To describe the influence of dengue immunity on the epidemiological, clinical, and biological characteristics of JEV infection (cohorts 1 and 2).
  • To develop new tools (Luminex serology) for diagnosis of JEV infection
  • To develop evaluate new tools (QUIASTAT) for diagnosis of meningitis and encephalitis infection in Cambodia
  • To model anti-JEV antibody kinetics over time following natural infection and vaccination (cohorts 1 and 2).
  • Using mathematical modeling of antibody titers, to quantify DENV and JEV interaction, e.g., to estimate the reduction of the risk of JEV infection following DENV infection.