Tetanus is caused by a toxin (poison) produced by a bacterium, Clostridium tetani. The C. tetani bacteria cannot grow in the presence of oxygen. They produce spores pthat are very difficult to kill as they are resistant to heat and many chemical agents.
C. tetani spores can be found in the soil and in the intestines and feces of many household and farm animals and humans. The bacteria usually enter the human body through a puncture (in the presence of anaerobic [low oxygen] conditions, the sporeswill germinate). Tetanus is not spread from person to person.
The incubation period varies from 3-21 days, with an average of eight days. The further the injury site is from the central nervous system, the longer the incubation period. The shorter the incubation period, the higher the risk of death.
The symptoms of tetanus are caused by the tetanus toxin acting on the central nervous system. In the most common form of tetanus, the first sign is spasm of the jaw muscles, followed by stiffness of the neck, difficulty in swallowing, and stiffness of the abdominal muscles. Other signs include fever, sweating, elevated blood pressure, and rapid heart rate. Spasms often occur, which may last for several minutes and continue for 3-4 weeks. Complete recovery, if it occurs, may take months.
Tetanus has a high fatality rate; during 1998-2000, the case-fatality rate for reported tetanus in the United States was 18%.
Laryngospasm (spasm of the vocal cords) is a complication that can lead to interference with breathing. Patients can also break their spine or long bones from convulsions. Other possible complications include hypertension, abnormal heart rhythm, and secondary infections, which are common because of prolonged hospital stays. Obviously, the high possibility of death is a major complication.
The diagnosis of tetanus is based on the clinical signs and symptoms only. Laboratory diagnosis is not useful as the C. tetani bacteria often cannot be recovered from the wound of an individual who has tetanus, and conversely, can be isolated from the skin of an individual who does not have tetanus.
Tetanus bacilli live in the soil, so the most dangerous kind of injury involves possible Contamination with dirt, animal feces, and manure. Although we have traditionally worried about deep puncture wounds, in reality many types of injuries can allow tetanus bacilli to enter the body. In recent years, a higher proportion of cases had minor wounds than had major ones, probably because severe wounds were more likely to be properly managed. People have become infected with tetanus following surgery, burns, lacerations, abrasions, crush wounds, ear infections, dental infections, animal bites, abortion, pregnancy, body piercing and tattooing, and injection drug use. People can also get tetanus from splinters.
Any wound that may involve contamination with tetanus bacilli should be attended to as soon as possible. Treatment depends on your vaccination status and the nature of the wound. In all cases, the wound should be cleaned. Seek treatment immediately and bring your immunization record with you. With wounds that involve the possibility of tetanus contamination, a patient with an unknown or incomplete history of tetanus vaccination needs a tetanus-and diphtheria-containing shot (Td or Tdap) and a dose of tetanus immune globulin (TIG) as soon as possible. A person with a documented series of three tetanus and diphtheria-containing shots (Td or Tdap) who has received a booster dose within the last ten years should be protected. However, to ensure adequate protection, a booster dose of vaccine may still be given if it has been more than five years since thedose and the wound is other than clean and minor.
Tetanus first became a reportable disease in the late 1940s. At that time, there were 500-600 cases reported per year. After the introduction of the tetanus vaccine in the mid-1940s, reported cases of tetanus dropped steadily. During 1990-2001, a total of 534 cases of tetanus were reported. Most (56%) of these cases occurred among adults age 19-64 years and 38% were among persons age 65 years or older. Almost all cases of tetanus are in persons who have never been vaccinated, or who completed their childhood series, but did not have a booster dose in the preceding 10 years.
Neonatal tetanus is a form of tetanus that occurs in newborn infants, most often through the use of an unsterile cutting instrument on the unhealed umbilical stump. These babies usually have no temporary immunity passed on from their mother because their mother hasn’t been vaccinated and therefore has no immunity. Neonatal tetanus is very rare in the United States (three cases reported during 1990-2004), but is common in some developing countries. It causes more than 215,000 deaths worldwide per year.
Yes! Tetanus disease does not cause immunity because so little of the potent toxin is required to cause the disease. Persons recovering from tetanus should begin or complete the vaccination series.