Tetanus is a potentially fatal disease: it acts very quickly and often kills before the body’s natural primary response can take place. There are about 1million cases of tetanus a year with between 300,000-500,000deaths. It is a global problem because tetanus spores, which cause the infection, are everywhere. However, due to vaccination programmes, tetanus is rare in the UK with only about 10 cases a year; the main problems are encountered in developing countries where vaccines may be too expensive and equipment may not be properly sterilised.

Tetanus is caused by gram positive, obligate anaerobic bacteria: Clostridium tetani which affects skeletal muscles.”Gram positive” means that the bacteria has a thick cell wall, while “obligate anaerobe” means that the bacteria can’t survive in the presence of oxygen and survive using anaerobic respiration (without oxygen). The bacteria releases a neurotoxin called tetanospasmin which binds irreversibly to neurones; these are nerve cells that carry waves of electrical activity, known as nerve impulses. When the toxin binds to the neurone it prevents the inhibition of the motor reflex response to sensory stimuli. The motor reflex response is a rapid response to a stimulus, for example the knee jerk is a motor reflex response to tapping a specific nerve, and in this case it prevents us from falling over. However the toxin stops the nerve from suppressing the movement once the stimuli has gone so the movement continues as a muscle spasm which is characteristic of tetanus.

Causes:

• Bacterium Clostridium tetani.
• Contamination of a puncture wound, e.g.: a piercing.
• Ear infections as bacteria may enter through ear.
• Using unsterile equipment in surgery or other similarly invasive procedures such as tattooing and body piercing.

Tetanus is associated with rust which is a little misleading. You are not infected by the rust itself it’s just that rust is a rough surface which makes a very good habitat for the endospores of C.tetani. Therefore if you suffer a puncture wound from a rusty object such as a nail, endospores might be delivered into the wound and then you become infected. Endospores are non-metabolising structures that metabolise and cause infection once they are in an adequate environment. Since this bacterium is an obligate anaerobe it can’t live in the presence of oxygen, but a puncture wound is a good environment because it is a low oxygen environment.

The disease is common in areas with hot, damp climates that have soil rich in organic matter, or places where soil is treated with manure. This is because the spores of C.tetani are widely distributed in the intestines of animals such as horses, rats, sheep, cattle, dogs and chickens, and therefore are present in manure. Spores can also be found on skin surfaces and in contaminated heroin.

The incubation period for tetanus is usually between 3 and 21 days, so it may be a while before you are aware that you are infected, especially if the site of contamination was a small cut that you were hardly aware of, such as a thorn prick. The further from the central nervous system the contaminated wound is the longer the incubation period. However, the shorter the incubation period the higher the chance of death. Normally symptoms are present after 8 days and they last between 4-6weeks.

Symptoms:

• Firstly muscle spasms occur near the wound
• Muscle spasm spread to the jaw making it difficult to swallow or open your mouth, hence the name lockjaw
• Muscle spasms spread to the face, neck, chest, stomach wall, arms and legs.
• Sensitivity to touch
• High fever
• Sore throat
• Rapid heart beat
• General tiredness and weakness
• Sweating
• Can’t pass urine
• Difficulty with breathing due to chest muscle spasms and lockjaw
• Headache
• Bleeding into the bowels
• Diarrhoea

Direct causes of death include:

• Blood poisoning
• Suffocation
• Cardiac arrest (heart attack)
• Kidney failure
• Exhaustion.

Complications:

• Development of pneumonia and other infections
• Fractures of long bones due to severe muscle contractions
• Spinal compression fractures
• Breathing problems
• Coma.

People who are most at risk are:

• Over 60s as the vaccine was introduced in the 1960s so they may not be properly immunised
• People who aren’t immunised or have not had the full vaccination course (tetanus occurs almost exclusively in people who are unvaccinated or inadequately immunised.)
• Those who live in poverty where vaccines may not be available or medical treatment is not adequate and equipment isn’t properly sterilised.
• Intravenous drug users.

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