Not an expert on the subject by any means, but i do know a little bit. The biggest issues with using prions as a bioterrorism vector are:

1. Sourcing prions. There isn’t really any reason that anyone would want prions outside of a laboratory environment. They aren’t exactly something you can go pick up at the store or synthesize yourself. Getting enough to poison the food chain would likely be significantly more difficult than something more common and deadly like botulism.

2. Poisoning. If you wanted to use prions en masse as a poison, you’re going to need to get access to a meat processing plant and figure out a way to actually do the poisoning. This might not be the biggest hangup considering recent revelations (boars head meat). Still, meat is not as easy to adulterate as something like produce, where you can simply spray the food with your poison at virtually any point in the supply chain.

3. Time. Prions take forever to kill. For mad cow, we’re talking years. For CJD, were talking decades. Terrorists typically like to create terror to make a statement. Are prion diseases scary? Yes, but the fact that you wouldn’t even know about the poisoning for years makes it pretty bad as a tool for terror.

Essentially, no one uses prions as a weapon because if you’re going to carry out a bioterror attack, there are much easier to acquire and more effective agents. That being said, please do not commit bioterrorism or any other form of terrorism. It’s very mean and unnecessary.