Tetanus commonly known as "lockjaw" is a very serious illness caused by the Clostridium tetani (C. tetani). The C. tetani bacteria live in soil, saliva, dust, and manure. These bacteria enter the body through a contaminated deep cut or from a puncture wound. They produce a neurotoxin which causes the body to develop severe painful muscle spasms. Tetanus is a medical emergency and should be seen at a hospital. Without immediate treatment tetanus can result in death.