There is actually a module which is currently under development to perform virus scanning, that being File::Scan - I last had a look at this module about a month ago when I first saw it on CPAN. At that stage, it was still quite embryonic in terms of the number of computer virii recognised and the lack of any 'clean-up' ability for identified infected files. As a positive however, this module can also identify files as "suspicious", requiring further examination.

However, when I last looked at this module, while it included a virus 'definition' file, at appeared that all virus identification was hard-coded into the module code - The migration of this identification code to make use of the definition would however appear to an intended direction for the development of this module.

Also too, depending upon your requirements, there are a number of Perl applications which integrate with mail transport agents and third-party anti-virus tools for the scanning of incoming mail - Examples of such applications include the Anomy mail sanitizer and AMaViS.