hepatitis E virus
Meaning of hepatitis E virus: A liver virus carried by contaminated water and by undercooked meat, usually brief but dangerous in late pregnancy.
Definition of hepatitis E virus
Hepatitis E virus is a small RNA virus that infects the liver and causes hepatitis, meaning inflammation of the liver. Most infections clear on their own within weeks, and many cause no symptoms at all. It passes from stool to mouth, chiefly through drinking water contaminated with sewage and through undercooked pork, wild game and shellfish.
How does it spread?
The virus exists in several genotypes that behave like two different diseases.
| Genotype group | Main route | Pattern |
|---|---|---|
| 1 and 2 | Drinking water contaminated with sewage | Large outbreaks, humans the only host, mainly in parts of Asia and Africa |
| 3 and 4 | Undercooked pork, wild boar, deer, shellfish | Scattered individual cases with an animal reservoir, including in high-income countries |
Transmission from an infected food handler, the usual route for hepatitis A, is not the main way this virus travels. Spread through transfused blood and from mother to baby also occurs.
What does infection look like?
After an incubation period of several weeks, symptoms resemble other viral hepatitis: tiredness, loss of appetite, nausea, discomfort under the right ribs, dark urine, pale stool and jaundice. Blood tests show sharply raised liver enzymes. Joint pain and rash occur in some. Recovery is usual within about four to six weeks, and the diagnosis rests on antibodies against the virus and on detecting its genetic material.
Who is at higher risk of severe disease?
Three groups stand out. In pregnancy, particularly the later months and particularly with genotype 1, infection can progress to liver failure and the death rate is far higher than in the general population. In people with existing scarring of the liver, a new infection can tip a stable liver into failure. People whose immune system is suppressed, such as transplant recipients, may fail to clear genotype 3 and carry it for months or years with progressive scarring, a chronic course once thought impossible for this virus.
How does it compare with hepatitis B?
Both damage the liver, and the resemblance ends there. Hepatitis B virus spreads through blood, sexual contact and childbirth, embeds itself in liver cell DNA, and frequently becomes lifelong with a raised risk of liver cancer. Hepatitis E spreads by the stool to mouth route, is not built into the host genome, and in a person with normal immunity it does not persist.
Also known as
Used in a sentence
Hepatitis E virus RNA was detected in a patient with jaundice and markedly raised transaminases.
Good to know
Hepatitis E is often assumed to be a travel-related infection, yet many cases in high-income countries are acquired locally from undercooked pork or game, and it can persist for years in people whose immune system is suppressed.
Word origin
Where “hepatitis E virus” comes from
Hepatitis joins the Greek hepar, meaning liver, with the ending -itis, meaning inflammation.