Hepatitis is the medical term for inflammation of the liver. Hepatitis may be acute (lasting only for the short term, after which a person recovers) or chronic (lasting for the long term, usually more than 6 months).
There are many causes of hepatitis, including viruses, alcoholism, and medications. Viral hepatitis is a major cause of chronic hepatitis in North America. There are many hepatitis viruses, including A, B, C, D, and E. The most common types in Canada are A, B, and C. There are also other viruses that can cause liver inflammation, like Epstein-Barr virus and cytomegalovirus, but these viruses are not called hepatitis viruses.
Hepatitis A and B infections are much more common in developing parts of the world. In Canada, hepatitis A and B are reported to infect about 300 and 150 people, respectively, per year. Since many infected people have no symptoms, however, we can assume the true rate of infection is higher than this.
Hepatitis A infection is most common in children and young adults, while hepatitis B infection is most common in adults between the ages of 30 and 60 years.