Compounds, methods, and compositions for the treatment of infections in or exposure to humans and other host animals of Flaviviridae viruses, including HCV, that includes the administration of an effective amount of a spiro[2.4]heptane as described herein or a pharmaceutically acceptable salt or prodrug thereof, optionally in a pharmaceutically acceptable carrier, are provided. The spiro[2.4]heptane compounds either possess antiviral activity, or are metabolized to a compound that exhibits such activity.