Hepatitis A is caused by the hepatitis A virus (HAV), which is usually found in the stool (bowel movements) of infected people. It is spread by:

• Putting something in your mouth that has been infected with the hepatitis A virus
• Drinking water contaminated by raw sewage
• Eating food contaminated by the hepatitis A virus, especially if it has not been properly cooked
• Eating raw or partially cooked shellfish contaminated by raw sewage
• Changing diapers and not adequately washing your hands—Food or work areas can be contaminated by the hepatitis A virus when food is handled.
• Having sex with a partner infected with the hepatitis A virus (particularly anal sex)

Hepatitis B is caused by the hepatitis B virus (HBV). This virus is spread through contact with bodily fluids of an infected person, such as blood, semen, vaginal fluids, and saliva. Hepatitis B can be spread by:

• Having sex with someone infected with hepatitis B or who is a carrier of hepatitis B
• Injecting illicit drugs, especially with shared needles
• Having a job that involves contact with bodily fluids
• Giving birth—A woman infected with hepatitis can pass the virus on to her baby during childbirth.
• Receiving a blood transfusion (especially prior to 1992 when better screening tests for hepatitis viruses were developed) or multiple transfusions of blood or blood products—This risk is greatly reduced with careful blood screening using modern techniques.
• Being bitten by someone whose saliva contains the virus
• Undergoing long-term kidney dialysis treatment—The dialysis machine can be tainted with HBV-infected blood.
• Receiving a tattoo, body piercing, or acupuncture with unsterilized or improperly sterilized equipment
• Receiving an HBV-infected organ transplant
• Sharing toothbrushes, razors, nail clippers, or other personal hygiene items that have HBV-infected blood or body fluids on them

Hepatitis C is caused by the hepatitis C virus (HCV). Hepatitis C virus is carried in the blood of people infected with the virus. It is primarily spread through contact with infected blood. It can occasionally be spread other ways. HCV can be spread by:

• Injecting illicit drugs with shared needles or sharing inhalation tubes when inhaling drugs
• Receiving HCV-infected blood transfusions, especially before 1992 when better screening tests were developed
• Receiving blood clotting products, especially older types that have not gone through modern purification and production methods
• Receiving an HCV-infected organ transplant
• Receiving long-term kidney dialysis treatment
• Sharing toothbrushes, razors, nail clippers, or other personal hygiene items that have HCV-infected blood on them
• Being accidentally stuck by an HCV-infected needle (a concern for healthcare workers)
• Receiving a tattoo, body piercing, or acupuncture with unsterilized or improperly sterilized equipment
• Giving birth
• Having sexual contact with someone infected with HCV

Hepatitis D is caused by the hepatitis D virus (HDV). It occurs only in people who have hepatitis B. Patients may have more severe disease and a higher risk of liver damage than those infected with HBV alone. It is spread through contact with infected blood and through:

• Having sexual contact with someone infected with HDV
• Living with an HDV-infected person—Close personal contact has been found to cause hepatitis D.
• Sharing toothbrushes, razors, nail clippers, or other personal hygiene items that have HDV-infected blood on them

Hepatitis E is caused by the hepatitis E virus (HEV), which can be found in the stool (bowel movements) of infected people. It is uncommon in the US, but it is a risk to international travelers. The virus is spread by:

• Putting something in your mouth that has been infected with the hepatitis E virus
• Drinking water contaminated by raw sewage
• Eating food contaminated by the hepatitis E virus, especially if it has not been properly cooked
• Eating raw or partially cooked shellfish contaminated by raw sewage