A North Korean defector was recently found with anthrax antibodies in his blood which has caused quite the stir, particularly among South Koreans and U.S. forces in South Korea.

There has been some confusion as to what this could mean. Why would someone have anthrax antibodies in his bloodstream? How is that indicative of some kind of weaponized anthrax? This article will discuss several of the more prominent possibilities.

But first: what are antibodies? Long story short, antibodies are small proteins that your body can make to neutralize diseases. You can develop antibodies through vaccinations or exposure to the biological agent (naturally occurring or weaponized) in question.

It’s important to realize that, with a thorough medical history and physical exam, health professionals would be able to determine the method of exposure to the defector. Here are four of the conclusions they may have come to: