Table 2.

Diagnostic criteria used to assess JE laboratory-confirmed patients.^*

Level 1	JEV RNA detected in any specimen by RT-PCR.
	Virus isolation by inoculation of any specimen in cell culture or animal with characteristic cytopathic effect and confirmation by detection of JEV RNA or virus antigen.
	JEV virus antigen detected from brain tissue or CSF by immunofluorescence or immunohistochemistry
Level 2	Seroconversion or ≥ 4x rise in anti-JEV Ab by seroneutralization or detection of neutralizing antibody in CSF; Samples should be tested alongside other endemic flaviviruses (e.g., dengue viruses)
Level 3	Anti-JEV IgM detected in CSF; Samples should be tested alongside other endemic flaviviruses (e.g., dengue viruses)
	Seroconversion or 4x rise in anti-JEV Ab HI, CF, IFA, or seroconversion by ELISA; Samples should be tested alongside other endemic flaviviruses (e.g., dengue viruses).
Level 4	Anti-JEV IgM detected in serum in one sample (acute/convalescent), or seroneutralisation tested in one sample or single high titer HI/CF/IFA; Samples must be tested alongside other endemic flaviviruses (e.g., dengue viruses)

RT-PCR = reverse transcription-polymerase chain reaction; RNA = ribonucleic acid; CSF = cerebrospinal fluid; Ab = antibody; ELISA = enzyme-linked immunosorbent assay; HI = haemagglutination inhibition; CF = complement fixation test; IFA = indirect immunofluorescence assay.

^*Confirmation of JE is categorized into levels 1-4 based on existing WHO and CDC criteria, such that level 1 provides the highest level of confidence.