I know of no way that either robots.txt or anti-virus can be used to block site visitors from specific regions. If you have information to the contrary, please explain in more detail.
As @bluedreamer has already mentioned, you can block specific IP addresses, but that would be done in the .htaccess file, not robots.txt.
Search engines have no way of knowing how much traffic your site is attracting, beyond that which comes directly from them. (Google has stated that it does not use analytics data in search rankings.)