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Pertussis, also known as whooping cough or 100-day cough, is a highly contagious bacterial disease.〔 Initially, symptoms are usually similar to those of the common cold with a runny nose, fever, and mild cough. This is then followed by weeks of severe coughing fits. Following a fit of coughing, a high-pitched whoop sound or gasp may occur as the person breathes in.〔 The coughing may last for 10 or more weeks, hence the phrase "100-day cough". A person may cough so hard they vomit, break ribs, or become very tired from the effort.〔 Children less than one year old may have little or no cough and instead have periods where they do not breathe.〔(【引用サイトリンク】url=http://www.cdc.gov/pertussis/about/signs-symptoms.html )〕 The period of time between infection and the onset of symptoms is usually seven to ten days.〔 Disease may occur in those who have been vaccinated, but symptoms are typically milder.〔 Pertussis is caused by the bacterium ''Bordetella pertussis''. It is an airborne disease which spreads easily through the coughs and sneezes of an infected person. People are infectious to others from the start of symptoms until about three weeks into the coughing fits. Those treated with antibiotics are no longer infectious after five days. Diagnosis is by collecting a sample from the back of the nose and throat. This sample can then be tested by either culture or by polymerase chain reaction. Prevention is mainly by vaccination with the pertussis vaccine. Initial immunization is recommended between six and eight weeks of age, with four doses to be given in the first two years of life. The vaccine becomes less effective over time, with additional doses often recommended for older children and adults. Antibiotics may be used to prevent the disease in those who have been exposed and are at risk of severe disease. In those with the disease, antibiotics are useful if started within three weeks of the initial symptoms, but otherwise have little effect in most people. In children less than one year old and among those who are pregnant, they are recommended within six weeks of symptom onset. Antibiotics used include erythromycin, azithromycin, or trimethoprim/sulfamethoxazole.〔 Evidence to support the effectiveness of medications for the cough is poor. Many children less than a year of age require hospitalization.〔 An estimated 16 million people worldwide are infected per year.〔 Most cases occur in the developing world, and people of all ages may be affected.〔〔 In 2013, it resulted in 61,000 deaths – down from 138,000 deaths in 1990. Nearly 2% of infected children less than a year of age die.〔 Outbreaks of the disease were first described in the 16th century. The bacterium that causes the infection was discovered in 1906. The vaccine became available in the 1940s. ==Signs and symptoms== The classic symptoms of pertussis are a paroxysmal cough, inspiratory whoop, and fainting, or vomiting after coughing. The cough from pertussis has been documented to cause subconjunctival hemorrhages, rib fractures, urinary incontinence, hernias, and vertebral artery dissection.〔 Violent coughing can cause the pleura to rupture, leading to a pneumothorax. Vomiting after a coughing spell or an inspiratory whooping sound on coughing, almost doubles the likelihood that the illness is pertussis. The absence of a paroxysmal cough or posttussive emesis, though, makes it almost half as likely.〔 The incubation period is typically seven to ten days, with a range of four to 21 days and rarely as long as 42 days,〔(Pertussis (whooping cough) ), New York State Department of Health, Updated: January 2012, retrieved 8 June 2013.〕 after which mild respiratory symptoms, mild coughing, sneezing, or runny nose usually occur. This is known as the catarrhal stage. After one to two weeks, the coughing classically develops into uncontrollable fits, each with five to ten forceful coughs, followed by a high-pitched "whoop" sound in younger children, or a gasping sound in older children, as the person tries to inhale (paroxysmal stage). Fits can occur on their own or can be triggered by yawning, stretching, laughing, eating, or yelling; they usually occur in groups, with multiple episodes on an hourly basis throughout the day. This stage usually lasts two to eight weeks, or sometimes longer. A gradual transition then occurs to the convalescent stage, which usually lasts one to two weeks. This stage is marked by a decrease in paroxysms of coughing, both in frequency and severity, and a cessation of vomiting. A tendency to produce the "whooping" sound after coughing may remain for a considerable period after the disease itself has cleared up. 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「Pertussis」の詳細全文を読む スポンサード リンク
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