Tetanus

Tetanus, also known as lockjaw, is a serious but preventable disease that affects the body's muscles and nerves. It typically arises from a skin wound that becomes contaminated by a bacterium called Clostridium tetani, which is often found in soil.

Once the bacteria are in the body, they produce a neurotoxin (a protein that acts as a poison to the body's nervous system) known as tetanospasmin that causes muscle spasms. The toxin first affects nerves controlling the muscles near the wound. It can also travel to other parts of the body through the bloodstream and lymph system. As it circulates more widely, the toxin interferes with the normal activity of nerves throughout the body, leading to generalized muscle spasms. Without treatment, tetanus can be fatal.

In the United States, most cases of tetanus follow a cut or deep puncture injury, such as a wound caused by stepping on a nail. Sometimes the injury is so small that it is never seen by a doctor. Injuries that involve dead skin (such as burns, frostbite, gangrene, or crush injuries) are more likely to cause tetanus. Wounds contaminated with soil, saliva, or feces - especially if not properly cleaned - and skin punctures from nonsterile needles (such as with drug use or self-performed tattooing or body piercing) are also at increased risk.

Another form of tetanus, neonatal tetanus, occurs in newborns who are delivered in unsanitary conditions, especially if the umbilical cord stump becomes contaminated. Prior to immunizations, neonatal tetanus was much more common in the United States. Now, routine immunizations for tetanus produce antibodies that mothers pass to their unborn babies. These maternal antibodies and sanitary cord-care techniques have made newborn tetanus very rare in developed countries.

In fact, tetanus in general is rare in the United States and other nations with tetanus vaccination programs - fewer than 50 cases of tetanus have been reported each year in the United States since 1995. However, many developing countries have no effective prevention and immunization programs against tetanus, so the disease is much more common there.