WordPress in itself is very safe and secure platform, however there are chances that your blog may get affected because of loopholes in your themes.
Antivirus for WordPress is a useful plugin that will scan your templates and also can monitor it on a daily basis for malicious injections in the themes.
You can also setup the Antivirus plugin to run a check daily and send you a email if it finds anything wrong in your templates, definitely another good tool to keep your blog safe and secure.
Credit WebLogTools.
