What Is Hepatitis E?

Overview

Hepatitis E is a viral infection that has clinical and morphological characteristics of acute hepatitis. It was formerly known as enterically (fecal-oral route) transmitted non-A, non-B hepatitis.  It is hypothesised that the hepatitis E virus (HEV) infection may have originally been widespread throughout the world and has only lately been limited to a few specific geographic areas, such as Asia and Africa.¹  Since the virus is frequently waterborne, infection is more likely to happen in areas with poor sanitation and a limited supply of clean water. The hepatitis E virus was first identified in the late 1970s. There are four known strains of the HEV that can infect humans, with HEV1 and HEV2 being the predominant agents responsible for infection outbreaks. HEV is thought to be responsible for 20.1 million infections per year in Africa and Asia combined, with 3.4 million individuals suffering from symptomatic cases of acute hepatitis and 70,000 fatalities being recorded as an outcome of acute liver failure.²

Causes of hepatitis E

Hepatitis E is caused by a HEV infection. The virus has different modes of transmission and hence, the cause of the infection can largely differ from person to person. The HEV can spread in the following ways:

• Faecal-oral route:

The primary mode of transmission of the HEV during epidemics is through the faecal-oral pathway. The majority of epidemics that have been recorded have been linked to drinking water being contaminated with faecal matter. When water supplies become contaminated after severe rains or flooding, outbreaks typically follow. Several epidemics have happened during hot, humid months when there is a higher risk of infection due to the decreased water flow in rivers and streams

• Person-to-person transmission:

This route of transmission for the HEV appears to be rare during hepatitis E outbreaks. Some studies have shown that only between 0.7–2.2% of hepatitis E cases in households were a result of secondary transmission.³ When a household does experience several cases of infection, this is more likely to be due to exposure to a common source of contaminated water than from person-to-person transmission

• Sporadic infections:

Sporadic HEV infections can also occur. These typically have an uncertain source of infection and can have a resurgence in some patients. Water contamination appears to be the most probable route of transmission. Yet, consuming undercooked pork has also been associated with HEV infections

• Vertical transmission:

It is known that HEV can be transmitted vertically, from an infected child-bearing parent to their unborn child while it is still in the uterus⁴ 

There is no proof that HEV is transmitted sexually. However, an Italian study found that 20% of homosexual men had anti-HEV antibodies, compared to only 3% of intravenous drug users. This suggests sexual transmission of the HEV is conceivable.⁵

The frequency of anti-HEV antibodies among individuals with haemophilia, thalassaemia, and intravenous drug users is comparable to the prevalence rates for the general population. Hence, there is no evidence to suggest that the HEV may be transmitted during the transfusion of blood or blood products.^5,6

Signs and symptoms of hepatitis E

HEV enters the host and travels to the liver through unidentified pathways. The virus replicates within the cytoplasm of liver cells, which are also known as hepatocytes. About a week before symptoms appear, and for the duration of the infection, HEV particles are excreted in the faeces. A brief period of flu-like fever and nausea precedes clinically overt hepatitis. Most HEV infections either disappear after the early flu-like phase or continue to be asymptomatic. 

Yet, HEV infections can become symptomatic and can vary in severity. Common symptoms of hepatitis E include:^1,2,7

• Jaundice
• Feeling unwell
• Loss of appetite
• Stomach discomfort 
• Hepatomegaly (abnormally enlarged liver)
• Nausea
• Vomiting 
• Fever 
• Pruritus (Itchy skin)

Management and treatment for hepatitis E

Molecular and immunological electron microscopy to detect the virus in faeces or serum, as well as serological assays to identify IgM or IgG class anti-HEV antibodies in the blood are laboratory tests that can help diagnose human HEV infection. Additionally, reverse transcription polymerase chain reaction (RT-PCR) can be used to identify HEV genomic sequences in serum and stool samples.

To avoid contracting HEV, it's crucial to practice good hygiene and sanitation. Some important steps to take to ensure this are:^1,7

• While travelling in regions with limited access to safe drinking water, boil or chlorinate water (or buy bottled water) 
• Frequently wash your hands frequently for at least 20 seconds with soap and water 
• Avoid the consumption of undercooked and raw meat
• Exercise extra caution if you are visiting an area where the risk of HEV transmission is higher than usual, especially if you are pregnant or have an impaired immune system
• Vaccinate yourself against hepatitis E

The United Nations 2030 Sustainable Development Agenda and the WHO call for the global eradication of hepatitis. They aim to achieve this by:

• Increasing public awareness
• Fostering collaboration
• Mobilising resources needed to tackle hepatitis infections
• Enhancing health equity in regards to the hepatitis response
• Developing evidence-based hepatitis policies and gathering experimental data 
• Expanding access to screening, care, and treatment programs

To raise awareness about viral hepatitis, the WHO sponsors annual World Hepatitis Day campaigns. WHO has chosen the theme "One Life, One Liver," for World Hepatitis Day 2023 to focus on the need to preserve your liver by preventing liver disease and hepatitis infections.

FAQs

How is hepatitis E diagnosed?

The detection of specific anti-HEV immunoglobulin M and G (IgM and IgG) antibodies against the virus in a person’s blood is typically sufficient for the diagnosis of hepatitis E infection in regions where it is prevalent. 

How can I prevent hepatitis E?

The availability of clean drinking water and proper sanitation are the two main factors that can help prevent hepatitis E. Avoiding the consumption of raw pork is also advised.

Is hepatitis E contagious?

Although it is extremely uncommon, the virus has been seen to spread from person to person through solid organ transplantation, sexual activity and blood transfusion.⁵

Who is at risk of hepatitis E?

You have the highest risk of contracting hepatitis E when you are visiting places with poor sanitation that have limited access to clean drinking water.

How common is hepatitis E?

An estimated 20 million HEV infections occur annually, resulting in an estimated 3.3 million cases of hepatitis E where patients experience symptoms.²

When should I see a doctor?

It is advisable to visit a doctor if you present with symptoms of hepatitis E, especially after travelling to a country with poor sanitation, or if you palpate an abnormally enlarged liver.

Summary

Hepatitis E is a viral illness. It is thought to be responsible for 20.1 million infections per year. The primary mode of transmission of hepatitis E is through the faecal-oral pathway, which is linked to drinking water that has been contaminated by faecal matter. Symptoms can range from general signs of poor well-being, like fever, nausea, and loss of appetite, to more specific liver-related symptoms, such as jaundice, hepatomegaly, and pruritis. Electron microscopy, serological assays, and reverse transcription polymerase chain reaction (RT-PCR) can be used to diagnose hepatitis E. To avoid contracting HEV, it is important to practice good hygiene and sanitation, boil or chlorinate water when there is no access to bottled water, and avoid consuming ice from an unknown water source. The WHO aims to eradicate Hepatitis E (and other forms of hepatitis) by 2030. You can play your part by receiving the hepatitis E vaccine and by raising awareness about the existence of this disease.