The Hepatitis E virus (HEV) is a pathogen that primarily targets the liver, causing inflammation and damage. It is a significant global public health concern, affecting millions annually. Understanding HEV is important due to its widespread presence and varied impact.
What is Hepatitis E?
Hepatitis E is caused by the Hepatitis E virus, an RNA virus from the Hepeviridae family. It differs from other hepatitis viruses, primarily causing acute liver inflammation, though chronic infections can occur in specific populations.
Four main HEV genotypes affect humans. Genotypes 1 and 2 are found in human populations, often leading to outbreaks in developing regions. Genotypes 3 and 4 are zoonotic, circulating in animals like pigs, wild boar, and deer, and can transmit to humans. These zoonotic genotypes are more common in industrialized countries.
How Hepatitis E Spreads
Hepatitis E primarily spreads through the fecal-oral route. The most common source of infection, especially in regions with poor sanitation, is contaminated drinking water. Outbreaks often occur after heavy rainfall or flooding compromises water sources.
Consumption of undercooked meat, particularly pork, wild boar, or deer liver, is a significant source of HEV infection in industrialized nations. Shellfish, if harvested from contaminated waters and not cooked thoroughly, can also transmit the virus. Less common routes include blood transfusions and vertical transmission from an infected mother to her newborn during pregnancy or childbirth.
Recognizing Symptoms and Diagnosis
Many people infected with Hepatitis E experience no symptoms. When symptoms appear, they resemble other forms of acute viral hepatitis. Common signs include jaundice, fatigue, malaise, nausea, vomiting, and abdominal pain, particularly in the upper right quadrant.
Other symptoms can include a low-grade fever, dark urine, and light-colored stools. The incubation period ranges from 2 to 10 weeks. Diagnosis involves specific blood tests. Acute infection is confirmed by detecting IgM antibodies to HEV. IgG antibodies to HEV can also be measured to determine past exposure. Detecting HEV RNA in blood or stool samples confirms active viral presence.
Treatment and Prevention
For most individuals, acute Hepatitis E infection resolves spontaneously without specific medical intervention. Treatment focuses on supportive care, including rest, hydration, and avoiding liver-stressing substances. Hospitalization may be necessary for severe cases, especially if acute liver failure develops.
For chronic Hepatitis E infection, particularly in immunocompromised individuals, antiviral medication like ribavirin is used. This drug reduces the viral load and prevents progressive liver damage. Treatment duration varies.
Preventing Hepatitis E relies on public health measures and good personal hygiene. Ensuring access to safe drinking water is important. Proper sanitation practices limit transmission. Thorough handwashing and cooking meat and shellfish thoroughly are effective personal hygiene measures. A vaccine against HEV is available in some regions.
Who is at Risk for Severe Disease?
While Hepatitis E often results in a self-limiting illness, some populations face a higher likelihood of severe outcomes or chronic infection. Pregnant women are susceptible to severe disease. Infection during pregnancy can lead to a higher risk of acute liver failure, miscarriages, and mortality for both mother and fetus. Hormonal and immunological changes during pregnancy contribute to this.
Individuals with pre-existing chronic liver disease are also at increased risk. An HEV infection can accelerate liver damage in these individuals. Their compromised liver function makes it harder to clear the virus and manage the inflammatory response. Immunocompromised individuals are vulnerable to developing chronic HEV infection. Their weakened immune systems may fail to eliminate HEV, leading to persistent infection and progressive liver damage.