I am getting tons of pdf files in email. I want to know that does pdf file can contain a virus. Some of the files that I had received are unknown. That means I cannot locate the sender. I have a antivirus, but I am not sure whether it scans the file or not. A number of documents that I receive contains PO. I cannot ignore any of them. I want to know that does this thing can be effected with the virus. I had noticed that from some time my system is working very slow. The files take time to load up and I had also seen some antivirus warnings in recent time.