Hepatitis, often referred to as viral hepatitis, is a condition marked by inflammation of the liver. Several types of viruses can cause hepatitis, including hepatitis A, B, C, D, and E. Each type results from a different virus and spreads in different ways. Some hepatitis viruses are transmitted through contaminated food or water, while others are spread through contact with bodily fluids like blood or semen. Once inside the body, these viruses attack liver cells, leading to inflammation and potential liver damage or other serious complications.

Causes of Hepatitis A

Hepatitis A is caused by the hepatitis A virus (HAV) and leads to an acute, short-term infection. It is highly contagious and spreads mainly through the fecal-oral route. This means a person can become infected by consuming tiny, often invisible traces of feces from someone who has the virus. The most common ways this occurs are through eating or drinking contaminated food or water, engaging in certain sexual activities (such as oral or anal sex), or caring for someone who has hepatitis A.

Food can become contaminated if a person with hepatitis A doesn’t properly wash their hands before touching it. Contamination can occur at any point in the food supply chain—from growing and harvesting to preparation and serving. Hepatitis A is more common in areas with poor sanitation. In countries where the hepatitis A vaccine is widely available, cases are much less frequent.

Causes of Hepatitis B

Hepatitis B is caused by the hepatitis B virus (HBV), which spreads through contact with the bodily fluids of someone who is infected. These fluids include blood, semen, vaginal secretions, and even saliva. Transmission usually occurs through:

  • Sharing needles or syringes for injecting drugs, tattoos, or piercings

  • Having unprotected sex with someone who has hepatitis B

  • Using personal items contaminated with infected fluids, like razors or toothbrushes

  • Coming into contact with the open wounds or blood of an infected person

  • Childbirth, where the virus is passed from parent to child during delivery

Globally, hundreds of millions of people live with chronic hepatitis B, and new cases continue to emerge each year. In countries like the U.S., thousands of new infections occur annually, along with many people living with chronic forms of the disease.

Causes of Hepatitis C

Hepatitis C results from infection with the hepatitis C virus (HCV). It spreads primarily through exposure to infected blood. You may contract hepatitis C by:

  • Sharing needles or syringes with an infected person

  • Receiving a blood transfusion or organ transplant before modern screening methods were introduced in the early 1990s

  • Having unprotected sex with someone who has hepatitis C

  • Sharing personal items that may contain blood, like nail clippers or toothbrushes

  • Coming into contact with open sores or blood

  • Childbirth, when passed from an infected parent to their baby

Hepatitis C may begin as an acute infection, but for more than half of those infected, it becomes a chronic, lifelong condition unless properly treated. Millions of people around the world live with chronic hepatitis C, and new infections continue to occur.

Causes of Hepatitis D

Hepatitis D is caused by the hepatitis D virus (HDV), which is unique in that it can only infect people who already have hepatitis B. The HDV virus requires HBV in order to replicate in the body.

Transmission occurs in the same way as hepatitis B—through contact with infected blood or other bodily fluids. A person can be infected with both viruses at the same time, or they may get hepatitis D later, which is known as a superinfection. This dual infection can increase the severity of liver damage and may result in acute or chronic illness.

Causes of Hepatitis E

Hepatitis E is caused by the hepatitis E virus (HEV) and is a leading cause of acute hepatitis in regions with poor sanitation and limited access to clean water.

Like hepatitis A, HEV is spread through the fecal-oral route. People usually become infected by drinking contaminated water or eating food prepared in unsanitary conditions. In some cases, hepatitis E can also spread through the consumption of undercooked or raw pork, shellfish, or deer meat. While it is typically a short-term illness, it may become chronic in people who have received organ transplants.

Is Hepatitis Hereditary?

Viral hepatitis is not inherited from your parents. However, some research suggests that genetics might play a role in how severe the illness becomes or whether it turns into a chronic infection. Current studies are exploring how your genes may influence your immune system's ability to respond to hepatitis B and C.

Who Gets Hepatitis?

Hepatitis affects people of all ages and backgrounds around the world. However, certain groups are at higher risk:

  • Age: Hepatitis can affect anyone, but younger people—especially infants—are more likely to develop chronic infections if exposed at a young age.

  • Sex: People assigned male at birth tend to have higher rates of hepatitis B and C, often due to factors like intravenous drug use or higher-risk sexual behaviors.

  • Ethnicity: Infection rates vary by ethnicity and geography. For instance, in the U.S., hepatitis B is more common among people of Asian, Pacific Islander, and African descent, while hepatitis C is more prevalent among Native American and Black populations.

Risk Factors

Certain behaviors, environments, and health conditions can increase your risk of getting viral hepatitis, including:

  • Poor access to clean water or sanitation

  • Living in the same household as someone with hepatitis

  • Having sexual contact with someone who has hepatitis

  • Using injectable drugs and sharing needles or equipment

  • Traveling to or living in areas with high hepatitis rates

  • Working in healthcare or public safety roles

  • Having other health issues such as HIV, sexually transmitted infections, kidney failure, or liver disease

  • Experiencing homelessness

  • Being incarcerated

A Quick Review

Hepatitis is a liver inflammation caused by various viruses—A, B, C, D, and E—each spreading in different ways. Contaminated food or water and contact with infected blood or bodily fluids are the most common routes of transmission. While some hepatitis types are short-term illnesses, others can become chronic and lead to lasting liver damage.

Anyone can get hepatitis, but people in areas with poor sanitation or certain health risks are more vulnerable. You can reduce your risk through vaccination, good hygiene practices, safe sex, and avoiding shared needles or syringes.