Can you get Tetanus from a rusty nail?

A look at lockjaw

Also in this week's column:

• Why do babies blink less often than adults?
• Can a corpse burp?

Can you get Tetanus from a rusty nail?

Asked by Belinda Smith of Columbus, Ohio

Whether it is rusty or not, any object that punctures or damages the skin can lead to tetanus. According to Dr Andrew Lloyd, an infectious disease physician in Sydney, Australia: "If you get a deep wound in a dirty environment, dirt contaminated with Clostridium tetani could enter the wound. The fact that the nail is rusty has no affect on whether or not tetanus develops."

Why is Tetanus called "Lockjaw"?

The uncontrollable muscle spasms and muscle rigidity that are the most characteristic symptom of tetanus very frequently affect the face. The mouth does not open and the jaw seems as if it were made of stone. The jaw seems as if it is locked shut, hence the rather apt description of "lockjaw".

What is Tetanus?

Tetanus is an acute and often fatal infectious disease caused by the anaerobic, spore-forming bacillus Clostridium tetani. This bacterium is common and widespread throughout the world. It can be found in soil, dust, feces, and even on the surface of the human skin.

The bacterium can only reproduce in the absence of oxygen. Thus, a deep wound becomes a good breeding ground for this bacterium. The bacteria usually enter the body through a contaminated puncture wound. Such wounds can be caused by metal nails, wood splinters, and insect bites. But the bacteria can also gain entry into the body via the site of a burn, frostbite, surgery, cutaneous ulcer, or injection.

An injury that creates dead skin can lead to tetanus. A mother can get tetanus from the uterus after birth. A special kind of tetatus (tetani neonatorium) occurs in newborn infants from the site of the umbilical cord.

The symptoms of tetanus can be severe. Once the bacteria get underneath the skin, they produce harmful toxins that attack the central nervous system. This results in uncontrollable muscle spasms and muscle rigidity throughout the body. The muscle spasms often look like unnatural stretches, hence the name "tetanus".

Tetanus is from the Greek "tetanos" which means "to stretch". Tetanus strikes about 100 people in the US each year. Approximately 25 per cent of these people die of the disease.

Physiological tetanus is a state of sustained muscular contraction without periods of relaxation caused by repetitive stimulation of the central nervous system at frequencies so high that individual muscle twitches are fused and cannot be distinguished from one another.

Tetany is the "hyperexitability" of nerves and muscles. Tetany can be brought about by many things including a severe vitamin D deficiency.

Historically, tetanus ravaged humans particularly soldiers during warfare. According to Dr JD Grabenstein and three colleagues from the US Office of the Surgeon General, writing in the 8 June 2006 Epidemiological Review, anti-tetanus vaccinations were introduced beginning in 1933. During World War II there were only 12 reported tetanus cases among the 12m US uniformed armed forces.

Stephen Juan, Ph.D. is an anthropologist at the University of Sydney. Email your Odd Body questions to [e-mail]