Computer viruses are unique to each operating system, so to scan for one, you need a virus scanning tool that's specific to your system. While it might seem like a rational solution to virus scanning if your company's network uses a mixture of Unix and Windows computers, scanning for Windows viruses on Unix systems does not make much sense: a Windows virus will probably not work on Unix systems, much less damage them. In addition, if you run a Windows virus scanner on a Unix system through third-party applications, it most likely won't function correctly.