Uploading Documents to Server, Dangerous?

Hi,

I have a web server running avast server edition. I’m developing a website with an upload form open to the public. It’s for uploading word documents.

I can check the extension and will only allow .doc, .docx and .pdf, anything else will be deleted.

The upload process cannot verify if a word/pdf document is actually a word/pdf document, and it can’t scan for viruses either.

I run a full system scan once a week. I suppose what I’m asking is firstly; if a document contains a virus, will it be harmful to my server even if I don’t open it, and secondly; is there anyway to scan files as/after they’re being uploaded using avast server edition?

Thanks.