Hepatitis E

2023 Case Definition (supplied by ADPH)

A. Clinical Criteria

An acute illness with discrete onset of any sign or symptom associated with acute viral hepatitis (e.g., fever, joint pain, loss of appetite/anorexia, nausea, vomiting, abdominal pain, clay colored stool, jaundice, or dark urine),

AND

Elevated total bilirubin levels (>3.0 mg/dL),

OR

Elevated serum alanine aminotransferase (ALT) levels (>200 IU/L)

OR

Aspartate aminotransferase (AST) levels (> 2.5 times the upper limit of normal 32 U/L for males, 26 U/L for female)

B. Laboratory Criteria

Confirmatory laboratory evidence:

• Detection of HEV RNA by nucleic acid amplification testing (NAAT) in serum or stool

OR

• Detection of HEV IgM in serum (CDC)

OR

• Detection of a four-fold increase in quantitative anti-HEV IgG in acute and convalescent serum specimens.

Note: Only testing confirmed or conducted by the CDC constitutes confirmatory laboratory evidence.

Only CDC laboratories are able to make a definitive diagnosis of HEV because there is no FDA approved diagnostic test for HEV (CDC reference)

AND

• The absence of a more likely diagnosis (Hepatitis A, Cytomegalovirus, and Epstein-Barr virus)

Note: The identification of anti-HEV IgM and rising titers of anti-HEV IgG antibodies are inadequate for diagnosis due to the lack of specificity for these antibodies (reference) based on the potential for false positives caused by cross reactivity:

Presumptive laboratory evidence

• Detection of HEV using any of the above diagnostic methods by a commercial or reference laboratory

C. Epidemiologic Linkage

• Epidemiological link to a setting with a confirmed source of HEV (e.g., household, meal sharer, travel partner, or sexual partner) 2-9 weeks prior to symptom onset

OR

• Epidemiologic link to a setting with a suspected source of HEV that is associated with at least one confirmed case

D. Case Classification:

Confirmed Case: A case meeting the clinical criteria with confirmatory laboratory evidence for HEV.

Probable: A case meeting the clinical criteria with presumptive laboratory evidence.

Date Posted: June 30, 2023