There are many different ways that a country could be attacked by a bio-weapon. For example dropping an anthrax bomb. This could infect a wide area with something that is easily transported. Also as seen in recent years the spores could be sent through the mail and hurt postal workers and people receiving the mail.
Some of the letters that were sent through the mail with anthrax spores inside.
Treatment If There Is a Bio-terror Attack
This is literally the island of anthrax. In 1942 the British government decided to use this remote island off the northwestern coast of Scotland. They chose this island to be there testing site for there new anthrax bomb they had developed. They wanted to use the bomb against the German forces in World War II. I think I will pass on the spinach grown there!