HEV transmission routes vary by genotype distribution. HEV-1 and HEV-2 are transmitted primarily by the faecal–oral route, mainly through drinking contaminated water. Zoonotic foodborne transmission of HEV-3 is associated with eating uncooked or undercooked meat and offal (including liver), of boar, deer, and pig. HEV-4, identified in China, Taiwan, and Japan, has been linked to transmission through contaminated food. HEV-7 infection has been associated with consumption of camel meat and milk.

Transfusion-related hepatitis E has been reported. Additionally, vertical transmission of HEV from people infected during pregnancy to their foetuses is common.

Incubation Period: Usually 15 to 60 days (mean: 40 days) after exposure.

Infectious Period: 2 to 3 weeks before and 1 week after onset of jaundice.

Clinical features

Symptoms include:

Fever
Fatigue
Loss of appetite
Nausea
Vomiting
Abdominal pain
Jaundice
Dark urine
Clay-coloured stool
Joint pain

Symptoms typically last 1 to 6 weeks. Most people with hepatitis E recover completely. In rare cases, acute hepatitis E can be severe and result in fulminant hepatitis. These patients are at risk of death.

Pregnant women experience a higher mortality rate. Cases of chronic hepatitis E infection have been reported in immunosuppressed people. These remain uncommon.

Risk factors

High-Risk Groups:

Pregnant women in the second or third trimester are at increased risk of acute liver failure, fetal loss and death.
People who have had solid organ transplants or chronic liver disease.
People with compromised immune systems.

High-Risk Food Items:

Contaminated drinking water.
Uncooked or undercooked pork, deer meat, and shellfish.

Diagnosis

Confirmation of HEV infection is achieved through the detection of specific anti-HEV immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies in the patient's serum, or by identifying HEV RNA in blood or stool samples.

Treatment and management

No specific treatment is available to alter the course of acute hepatitis E.

Hospitalisation is necessary for persons with fulminant hepatitis and should also be considered for symptomatic pregnant women.

Precaution, prevention, and control

General advice

Practice good hygiene.
Refrain from consuming water and ice of uncertain purity – boiling and chlorination of water can deactivate hepatitis E virus.
Avoid high-risk food items such as raw or undercooked pork, deer meat, and shellfish.

There is no hepatitis E vaccination available in Singapore.

Notification

Who should notify:

Laboratories

When to notify:

On laboratory confirmation

How to notify:

Please refer to the Infectious Disease Notification for more information.

Notification timeline:

As soon as possible. No later than 72 hours from the time of clinical or laboratory confirmation.

Resources

Please refer to the Weekly Infectious Diseases Bulletin for the number of confirmed acute hepatitis E cases in Singapore.