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Measles is extremely infectious and its continued circulation in a community depends on the generation of susceptible hosts by birth of children. In communities which generate insufficient new hosts the disease will die out. This concept was first recognized in measles by Bartlett in 1957, who referred to the minimum number supporting measles as the critical community size (CCS). Analysis of outbreaks in island communities suggested that the CCS for measles is c. 250,000. In 2011, the WHO estimated that there were about 158,000 deaths caused by measles. This is down from 630,000 deaths in 1990. In developed countries, death occurs in 1 to 2 cases out of every 1,000 (0.1% - 0.2%). In populations with high levels of malnutrition and a lack of adequate healthcare, mortality can be as high as 10%. In cases with complications, the rate may rise to 20–30%.〔(Measles ), World Health Organization Fact sheet N°286. Retrieved June 28, 2012. Updated February 2014〕 Increased immunization has led to an estimated 78% drop in measles deaths among UN member states.〔(【引用サイトリンク】url=http://www.un.org/millenniumgoals/reports.shtml )〕 This reduction made up 25% of the decline in mortality in children under five during this period. Even in countries where vaccination has been introduced, rates may remain high. In Ireland, vaccination was introduced in 1985. There were 99,903 cases that year. Within two years, the number of cases had fallen to 201, but this fall was not sustained. Measles is a leading cause of vaccine-preventable childhood mortality. Worldwide, the fatality rate has been significantly reduced by a vaccination campaign led by partners in the Measles Initiative: the American Red Cross, the United States Centers for Disease Control and Prevention (CDC), the United Nations Foundation, UNICEF and the WHO. Globally, measles fell 60% from an estimated 873,000 deaths in 1999 to 345,000 in 2005.〔(UNICEF Joint Press Release )〕 Estimates for 2008 indicate deaths fell further to 164,000 globally, with 77% of the remaining measles deaths in 2008 occurring within the Southeast Asian region.〔WHO Weekly Epidemiology Record, 4th December 2009 (WHO.int )〕 In 2006–07 there were 12,132 cases in 32 European countries: 85% occurred in five countries: Germany, Italy, Romania, Switzerland and the UK. 80% occurred in children and there were 7 deaths. Five out of six WHO regions have set goals to eliminate measles, and at the 63rd World Health Assembly in May 2010, delegates agreed a global target of a 95% reduction in measles mortality by 2015 from the level seen in 2000, as well as to move towards eventual eradication. However, no specific global target date for eradication has yet been agreed to as of May 2010.〔(【引用サイトリンク】title=Sixty-third World Health Assembly Agenda provisional agenda item 11.15 Global eradication of measles )〕〔(【引用サイトリンク】title=Sixty-third World Health Assembly notes from day four )〕 On January 22, 2014, the World Health Organization and the Pan American Health Organization declared and certified Colombia free of the measles while becoming the first Latin American country to abolish the infection within its borders.〔(Colombia, libre de sarampión y rubéola - Noticias de Salud, Educación, Turismo, Ciencia, Ecología y Vida de hoy - ELTIEMPO.COM )〕〔(Colombia fue declarada libre de sarampión y rubéol | ELESPECTADOR.COM )〕 In Vietnam, in the Measles Epidemic in the beginning of 2014, unto April 19 had 8,500 measles cases, 114 fatalities,〔(【引用サイトリンク】title=Vietnam minister calls for calm in face of 8,500 measles cases, 114 fatalities | Health | Thanh Nien Daily )〕 unto May 30 had 21,639 measles cases, 142 fatalities.〔(【引用サイトリンク】Bộ Y tế: "VN đã phản ứng rất nhanh đối với dịch sởi" )〕 ==Outbreaks== In 2007, a large outbreak in Japan caused a number of universities and other institutions to close in an attempt to contain the disease.〔(【引用サイトリンク】title=The Public Health Agency of Canada Travel Advisory )〕 Many children in ultra-Orthodox Jewish communities were affected due to low vaccination coverage. As of 2008, the disease is endemic in the United Kingdom, with 1,217 cases diagnosed in 2008, and epidemics have been reported in Austria, Italy and Switzerland.〔(Eurosurveillance—View Article )〕 On February 19, 2009, 505 measles cases were reported in twelve provinces in northern Vietnam, with Hanoi accounting for 160 cases.〔(【引用サイトリンク】url=http://www.lookatvietnam.com/2009/02/measles-spreads-to-12-provinces.html )〕 A high rate of complications, including meningitis and encephalitis, has worried health workers,〔(【引用サイトリンク】title=Measles outbreak hits North Vietnam )〕 and the U.S. CDC recommended all travelers be immunized against measles.〔(AmCham Vietnam | Public Notice: Measles immunization recommendation ).〕 Beginning in April 2009 there was a large outbreak of measles in Bulgaria, with over 24,000 cases including 24 deaths. From Bulgaria, the strain was carried to Germany, Turkey, Greece, Macedonia, and other European countries. Beginning in September 2009, Johannesburg, South Africa reported about 48 cases of measles. Soon after the outbreak, the government ordered all children to be vaccinated. Vaccination programs were then initiated in all schools, and parents of young children were advised to have them vaccinated. Many people were not willing to have the vaccination done, as it was believed to be unsafe and ineffective. The Health Department assured the public that their program was indeed safe. Speculation arose as to whether or not new needles were being used. By mid-October, there were at least 940 recorded cases, and four deaths. In early 2010, there was a serious outbreak of measles in the Philippines with 742 cases, leaving four unvaccinated children dead in the capital city of Manila. As of May 2011, over 17,000 cases of measles have so far been reported from France between January 2008 and April 2011, including 2 deaths in 2010 and 6 deaths in 2011.〔(【引用サイトリンク】 Epidémie de rougeole en France. Actualisation des données au 20 mai 2011 )〕 Over 7,500 of these cases fell in the first three months of 2011, and Spain, Turkey, Macedonia, and Belgium have been among the other European countries reporting further smaller outbreaks. The French outbreak has been specifically linked to a further outbreak in Quebec in 2011, where 327 cases have been reported between January and June 1, 2011, and the European outbreaks in general have also been implicated in further small outbreaks in the USA, where 40 separate importations from the European region had been reported between January 1 and May 20. Some experts stated that the persistence of the disease in Europe could be a stumbling block to global eradication. It has proven difficult to vaccinate a sufficient number of children in Europe to eradicate the disease, because of opposition on philosophical or religious grounds, or fears of side-effects, or because some minority groups are hard to reach, or simply because parents forget to have their children vaccinated. Vaccination is not mandatory in some countries in Europe, in contrast to the United States and many Latin American countries, where children must be vaccinated before they enter school.〔 In March 2013, an epidemic was declared in Swansea, Wales, UK with 1,219 cases and 88 hospitalizations to date. A 25-year-old male had measles at the time of death and died from giant cell pneumonia caused by the disease. There have been growing concerns that the epidemic could spread to London and infect many more people due to poor MMR uptake, prompting the Department of Health to set up a mass vaccination campaign targeted at one million school children throughout England. In late 2013, it was reported in the Philippines that 6,497 measles cases occurred which resulted in 23 deaths. In 2014 many unvaccinated US citizens visiting the Philippines, and other countries, contracted measles, resulting in 288 cases being recorded in the United States in the first five months of 2014, a twenty-year high. In January 2015, it was reported that nineteen people from three states who visited Disneyland or Disney California Adventure between Dec. 15 and Dec. 20 fell ill with measles. Sixteen of the cases were in California, two in Utah, and one in Colorado. Officials in California said that of the 16 cases in the state they have only verified that two were fully vaccinated against the disease. Some were partially vaccinated and at least two were too young to be vaccinated. Between the dates of January 1 and 28, 2015, most of the 84 people who were diagnosed with measles were either infected during their visit to Disneyland or by someone who visited the theme park.〔http://www.usatoday.com/story/news/2015/01/29/measles-outbreak-dangerousness/22521529/〕 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「Epidemiology of measles」の詳細全文を読む スポンサード リンク
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