28. Neurosyphilis
For those unaware, syphilis is a sexually transmitted disease. Truly, it is a bacterial infection that involves painful sores all over one’s lower extremities. However, it can break out in other areas too. Luckily, we can treat syphilis these days but that was not always the case. If left for people to battle, it can cause things like blindness, paralysis, and even tumors. Some would die from this stuff alone. Others were not so lucky and developed something known as Neurosyphilis.

Even those who got rid of normal syphilis can develop this. It causes several issues like a stiff neck, headaches, and nausea as well as problems with walking and numbness. The stuff that makes us worried about a real zombie apocalypse has to do with the walking aspect looking weird, on top of the mental issues it causes. Issues with depression, concentration, and even blackouts occur. Imagine how this could be used in the wrong hands. Add the fact that syphilis is so easy to give others.