An infectious disease, also known as lockjaw, caused by the exotoxin of Clostridium tetani. The organism may be isolated from fertile soil and the intestinal tract or fecal material of humans and other animals. Infection commonly follows dirt contamination of deep wounds or other injured tissues such as war wounds or crash injuries, burns, or septic abortion in which tissue necrosis is present. Any deep puncture wound that is contaminated by soil or feces is suspect. Tetanus neonatorum is frequent in developing countries if the cut surface of the umbilical cord is not properly treated. Use of understerilized syringe needles by drug users is also recognized as a cause of tetanus.