Viral hepatitis causes progressive inflammation of the liver that can be acute or chronic. It is caused by different viruses that cause different types of disease.

To date, 5 types of viral hepatitis are known to be caused by the so-called major hepatitis viruses: viral hepatitis A, B, C, D (delta) and E. In about 10-20% of cases, the agent responsible for the hepatitis remains unknown. All these forms of hepatitis cause severe liver pain and intense general symptoms. Some forms may also degenerate into serious illnesses such as liver cirrhosis, which destroys the liver, and liver cancer. Viral hepatitis A is transmitted via the fecal-oral route, and also sexually (oral and anal sex). Viral hepatitis B is the most widespread form, and is transmissible through sexual intercourse, but also through infected blood. Viral hepatitis C is transmitted more frequently through blood and more rarely through sexual intercourse. Viral hepatitis D can be transmitted through sexual intercourse, but it is rarer. Viral hepatitis E, isolated most recently, is a form that is similar to viral hepatitis A. Its transmission occurs via the fecal-oral route, and water contaminated by feces is the main vehicle for infection.

Those with viral hepatitis have a higher risk of acquiring another sexually transmitted disease, including HIV and syphilis. In Italy, hepatitis is included among the diseases for which obligatory notification by the doctor is required (Class II, relevant diseases because of high frequency and necessity for treatment).