Stock Photo: HEPATITIS VIRUS, TEM. Hepatitis virus colorized TEM. The type of hepatitis virus is unknown. This transmission electron micrograph TEM revealed numerous hepatitis virions, of an unknown strain of the organism. In the United States, viral hepatitis is an important public health problem because it causes serious illness, it affects millions, and it has a close connection with HIV. There are five identified types of viral hepatitis and each one is caused by a different virus. In the United States,