Zoonotic disease is hard to treat and most of them fatal. Zoonotic disease also easily spread so it could kill many people in short time. Since the disease could also be carried by animals so it is hard to be isolated. The damage that can be caused by the zoonotic disease is very high that it will easily cause panic, so it will be ideal for terrorism.
I think that people that do this kind of thing are just trying to scare everyone. Like, for example, In war they used to make people sick to kill off the competition. I think it was wrong!
