On a generic level, an antivirus engine can scan any file type provided it has the capability to understand the application signature. In the case of Office documents, it has become a standard to scan them for malicious Macros that are used to execute a command compromising the user's machine. The same applies to PDF files which can contain scripts that also infect the machine and make callbacks to remote botnet servers.

AV engines these days scan all but the most obscure file types and some of them can even tell you if a certain file is exploitable (not infected but having a vulnerability that can be exploited by a threat agent). It has become common practice to scan Office documents and PDF files. False positives might arise sometimes though.

On a basic level, an antivirus engine can scan any file type provided it has the capability to understand the application signature. In the case of Office documents, it has become a standard to scan them for malicious Macros that are used to execute a command compromising the user's machine. The same applies to PDF files which can contain scripts that also infect the machine and make callbacks to remote botnet servers.

AV engines these days scan all but the most obscure file types and some of them can even tell you if a certain file is exploitable (not infected but having a vulnerability that can be exploited by a threat agent). It has become common practice to scan Office documents and PDF files. False positives might arise sometimes though.