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Tetanus, also known as lockjaw, is an infection characterized by muscle spasms. In the most common type the spasms begin in the jaw and then progress to the rest of the body. These spasms usually last a few minutes each time and occur frequently for three to four weeks.〔 Spasms may be so severe that bone fractures may occur.〔 Other symptoms may include fever, sweating, headache, trouble swallowing, high blood pressure, and a fast heart rate.〔 Onset of symptoms is typically three to twenty-one days following infection. It may take months to recover. About 10% of those infected die. Tetanus is caused by an infection with the bacterium ''Clostridium tetani'',〔 which is commonly found in soil, dust and manure. The bacteria generally enter through a break in the skin such as a cut or puncture wound by a contaminated object.〔 They produce toxins that interfere with muscle contractions, resulting in the typical symptoms. Diagnosis is based on the presenting signs and symptoms. The disease does not spread between people.〔 Infection can be prevented by proper immunization with the tetanus vaccine. In those who have a significant wound and less than three doses of the vaccine both immunization and tetanus immune globulin are recommended. In those who are infected tetanus immune globulin or if not available intravenous immunoglobulin (IVIG) is used. The wound should be cleaned and any dead tissue removed.〔 Muscle relaxants may be used to control spasms. Mechanical ventilation may be required if a person's breathing is affected.〔 Tetanus occurs in all parts of the world but is most frequent in hot and wet climates where the soil contains a lot of organic matter.〔 In 2013 it caused about 59,000 deaths – down from 356,000 in 1990. Description of the disease by Hippocrates exists from at least as far back as the 5th century BCE. The cause of the disease was determined in 1884 by Antonio Carle and Giorgio Rattone at the University of Turin with a vaccine being developed in 1924.〔 == Signs and symptoms == Tetanus often begins with mild spasms in the jaw muscles—also known as lockjaw or trismus. The spasms can also affect the facial muscles resulting in an appearance called risus sardonicus. Chest, neck, back, abdominal muscles, and buttocks may be affected. Back muscle spasms often cause arching, called opisthotonos. Sometimes the spasms affect muscles that help with breathing, which can lead to breathing problems. Prolonged muscular action causes sudden, powerful, and painful contractions of muscle groups, which is called "tetany". These episodes can cause fractures and muscle tears. Other symptoms include drooling, excessive sweating, fever, hand or foot spasms, irritability, difficulty swallowing, suffocation, heart attack, breathing problems, irregular heartbeat, and uncontrolled urination or defecation. The episodes can also cause destruction of elements of the nervous system through viral cell exchange. With treatment about 10% of people who contract tetanus die.〔 The mortality rate is higher in unvaccinated people and people over 60 years of age.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「tetanus」の詳細全文を読む スポンサード リンク
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