Tetanus is a very serious disease caused by a toxin produced by the Clostridium tetani bacterium. The bacterium is an anaerobic rod that can also become a spore and is not able to survive in environments with high levels of oxygen. The spores are quite robust, able to resist heat and chemical agents.
Clostridium tetani spores are found in soil as well as the feces of certain animals, including horses, sheep, cattle, dogs, rats, and cats. For this reason, the disease is very common in people that work on farms with manure fertilized crops. The bacterium produces two types of toxins, only one of which is harmful to humans. That toxin is known as Tetanospasmin and is one of the most potent neurotoxins found on Earth.
The bacterium usually enters the body through a wound, where it can reproduce in a low oxygen part of the body. During this process, the bacterium produces the toxin, which spreads throughout the body and causes the symptoms associated with tetanus after a period of about two weeks. On a molecular level, the toxin essentially prevents neurotransmitters from creating impulses in the nervous system, making controlled movement difficult if not impossible.
Symptoms of tetanus include rigidity and spasms of muscles surrounding the skull. In many cases, the person's jaw becomes completely locked in place, making the victim incapable of opening their mouth to eat or chew.
Tetanus is usually diagnosed without the assistance of a blood test for the presence of the bacterium or toxin. This is due to the fact that the bacterium is difficult to isolate and the toxin does not produce unique indications in blood tests. If you do not have the vaccine and you receive a wound, clean it thoroughly with hydrogen peroxide. If you do contract the disease, doctors can treat the toxin with a chemical that disables toxin not already bound to nerve endings.
A common misconception is that stepping on a rusty nail is a sure fire way to get tetanus, however this is not true. Rusty nails are common causes of deep penetrating wounds that can easily allow the bacterium to infiltrate your body, however the bacterium is not more likely to be on a rusty nail than any other surface.
The best way to prevent yourself from getting tetanus is to get the vaccine. The tetanus toxin vaccine was developed in 1924 and used to protect soldiers in World War 2 from the disease.