Hepatitis E: Causes, Symptoms, Transmission, Treatment and Prevention

Hepatitis E is an inflammation of the liver caused by the hepatitis E virus (HEV). This virus has at least 4 different types: genotypes 1, 2, 3, and 4. Genotypes 1 and 2 have been discovered only in humans. Genotypes 3 and 4 circulate in several animals, including pigs, wild boars, and deer, without causing any disease, but they occasionally infect humans as well.

The virus is transmitted mainly through contaminated drinking water. The infection is usually self-limiting and resolves within 2-6 weeks. In some cases, it can progress into a serious disease known as fulminant hepatitis (acute liver failure), which can be fatal.

Mode of transmission

Hepatitis E infection is widespread worldwide and is common in underdeveloped countries with limited access to essential water, sanitation, hygiene, and health services. In these areas, the disease occurs both in the form of outbreaks and as sporadic cases. Outbreaks usually follow periods of fecal contamination of drinking water supplies.

Outbreaks also occur in conflict zones, such as in countries at war or in refugee camps, where sanitation and the supply of drinking water are difficult to maintain. Cases in these areas are mostly caused by infection with the genotype 1 virus and much more rarely by the genotype 2 virus.

In developed areas, hepatitis E infection is infrequent, with only occasional sporadic cases occurring. Most of these cases are caused by the genotype 3 virus and are triggered by infection with the virus from animals, usually through the ingestion of undercooked animal meat (including animal liver, especially pork). These cases are not linked to the contamination of water or other foods.

Symptoms

The incubation period following HEV exposure varies between 2 and 10 weeks. Infected individuals shed the virus starting from a few days before and up to 3-4 weeks after the onset of the disease.

In epidemic areas, symptomatic infection is more common in young adults aged between 15 and 40. In these areas, although infection also occurs in children, it often remains undiagnosed because they exhibit no symptoms or have only a mild form without jaundice.

Typical signs and symptoms of hepatitis include:

• mild fever, reduced appetite (anorexia), nausea, and vomiting lasting for a few days
• abdominal pain, itching, skin rashes, or joint pain
• jaundice and dark urine
• slightly enlarged and sensitive liver (hepatomegaly)

These symptoms are often indistinguishable from those experienced during other liver diseases and usually last 1-6 weeks.

In rare cases, acute hepatitis E can be severe and can lead to fulminant hepatitis (acute liver failure). These patients are at risk of death. Pregnant women with hepatitis E, especially those in the second or third trimester, are at an increased risk of acute liver failure, miscarriage, or death. Up to 20-25% of pregnant women may die if they contract hepatitis E in the third trimester.

Cases of chronic hepatitis E infection have been reported in immunocompromised individuals, particularly those who have received organ transplants and are taking immunosuppressive drugs, with genotype 3 or 4 HEV infection.

Diagnosis

Hepatitis E cases are not clinically distinguishable from other types of acute viral hepatitis. However, the diagnosis can often be strongly suspected in appropriate epidemiological contexts, for example, when multiple cases appear in localities in known endemic areas where there is a risk of water contamination.

Definitive diagnosis of hepatitis E infection is usually based on the detection of specific anti-HEV immunoglobulin M (IgM) antibodies against the virus in a person's blood. Rapid tests are also available.

Additional tests include reverse transcription polymerase chain reaction (RT-PCR) to detect hepatitis E virus RNA in the blood and feces.

Treatment

There is no specific treatment capable of altering the course of acute hepatitis E. Since the disease is usually self-limiting, hospitalization is generally not required. Avoiding unnecessary medications that have not been prescribed by a doctor is advised. Paracetamol and anti-vomiting medications should be used sparingly or avoided.

Hospitalization is necessary for people with fulminant hepatitis and should also be considered for symptomatic pregnant women.

Immunocompromised individuals with chronic hepatitis E benefit from specific treatment using ribavirin, an antiviral medication. In some specific situations, interferon has also been used successfully.

Prevention

Prevention is the most effective approach against infection. Transmission of HEV infection and hepatitis E can be reduced by:

• maintaining quality standards for public water supplies
• establishing adequate human fecal waste disposal systems
• maintaining norms of hygiene
• avoiding the consumption of water and ice from unsuitable areas

References
https://www.nfid.org/infectious-diseases/hepatitis/
https://www.who.int/news-room/fact-sheets/detail/hepatitis-e