Clam AntiVirus is an anti-virus toolkit for Unix. The main purpose of this
software is the integration with mail servers (attachment scanning). The
package provides a flexible and scalable multi-threaded daemon, a command-line
scanner, and a tool for automatic updating via Internet. The programs are based
on a shared library distributed with the Clam AntiVirus package, which you can
use in your own software.

You can build clamav with some conditional build switches;

(ie. use with rpm --rebuild):
--with[out] milter Build clamav-milter (disabled)