Hepatitis E Outbreak Toolbox

Hepatitis E Outbreak Toolbox

Updated | August 2024

Welcome to the Hepatitis E Outbreak toolbox

Key reference documents

Case definition

Case definitions may vary between organizations and may be adapted based on the specific context of an outbreak, available data, and evolving evidence. Users should refer to official guidelines from relevant public health authorities and adjust definitions as necessary to fit local epidemiological and operational needs.

WHO suggested outbreak case definition

Presumptive case:

A person with either or both of the following:

  • discrete onset of an acute illness with symptoms of acute infectious illness (fever, malaise, fatigue) AND signs of liver damage (anorexia, nausea, jaundice, dark urine, right upper quadrant tenderness, or
  • raised alanine aminotransferase (ALT) levels more than ten times the upper limit of normal laboratory levels1
Probable case:

Not applicable

Confirmed case:
  • laboratory confirmation: Immunoglobulin M (IgM) anti-HEV (Hepatitis E) positive;2 or 
  • an epidemiological link with a confirmed case.3

WHO surveillance case definition

1. Ten times the upper limit of normal (400 IU/L) is the threshold used by the United States Council of State and Territorial Epidemiologists (CSTE). Countries may also select lower (more sensitive) or higher (more specific) thresholds.

2. Adding a second test (e.g. Immunoglobulin A (IgA) anti-HEV, Immunoglobulin G (IgG) anti-HEV, or HEV-RNA) increases specificity to IgM anti-HEV.

3. Contact with a confirmed case/patient in the context of an etiologically confirmed outbreak.

 

Data collection tool

Laboratory confirmation