Method of treating hepatitis delta viral infection

A method for the treatment for hepatitis delta infection in a host, that includes administering an effective amount of a nucleoside or a nucleoside analog that suppresses the expression of the hepatitis B surface or preS1 antigen in the host 100-fold or more relative to pretreatment values in vivo; or to not more than 1 microgram per milliliter in vivo. In a preferred embodiment, the nucleoside is L-FMAU, or a pharmaceutically acceptable salt or prodrug thereof.