Viral hepatitis in Japan: update.

Viral hepatitis is defined as a hepatitis virus infection in which hepatic inflammation and necrosis lead to a characteristic feature. It is caused by at least five viral agents with specific epidemiological attributes and distinctive immunoserologic findings. The well-characterized forms are hepatitis A, B, C, D and E viruses. Recent status and the current progress of viral hepatitis in Japan are discussed in the present article.