Legionnaires' disease

Legionella pneumophila is a type of bacterial pneumonia caused by infection with Legionella pneumophila , a completely newly discovered bacterium that does not belong to any family or genus of known bacterial classifications. It is a type of respiratory infectious disease. It has no direct connection to veterans, but was named after an incident in 1976 when, of the approximately 4,000 people attending the annual general meeting of the American Legion, held at a hotel in Philadelphia from July 21 to 24, 184 people developed fulminant pneumonia, 24 of whom died, and 39 passersby who were exposed to the air conditioning emitted from the hotel where the meeting was held contracted the same disease, 5 of whom died. Through vigorous searches led by the CDC (Centers for Disease Control, the headquarters for infectious diseases prevention in the United States, which was reorganized as the Centers for Disease Control and Prevention in 1992), it was discovered to be caused by infection with a new type of gram-negative bacillus. Subsequent research has revealed that the bacteria can survive in water for long periods of time, is widely distributed in rivers and lakes around the world, and is particularly susceptible to outbreaks through the cooling water of air conditioning equipment, which provides favorable conditions for proliferation. This has led to the emphasis on hygiene control measures for building air conditioning. Since 1980, there have been reports of outbreaks and sporadic cases in Europe, as well as in Japan in Nagasaki, Sendai, and Fukuoka.

[Noriaki Yanagishita]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

既知細菌分類のどの科およびどの属にも該当しないまったく新しく発見された細菌であるLegionella pneumophilaの感染によって発症する細菌性肺炎で、呼吸器系伝染病の一種。在郷軍人とは直接的な関係はなく、1976年フィラデルフィア市の某ホテルで7月21～24日に開催されたアメリカ在郷軍人会の年次総会参会者約4000人のうち、184人に劇症肺炎が発生し、そのうち24人が死亡、また会場のホテルから排出された冷房風に当たった通行人39人が同じ病気にかかり、5人が死亡したという事件を契機として命名された疾患である。アメリカの公衆衛生局のCDC（伝染病予防本部Center for Disease Control。1992年アメリカ疾病対策センターCenters for Disease Control and Preventionに改組）を中心とした精力的な検索によって、新種のグラム陰性桿菌(かんきん)の感染によることがわかった。その後の研究により、水中に長期間生存が可能で、世界中の川や湖水にも広く分布し、とくに増殖の好条件がそろう空調設備の冷却水を介して集団発生する可能性が濃く、ビル冷房の衛生管理対策が重視されるようになった。1980年以来ヨーロッパをはじめ、日本でも長崎、仙台、福岡で集団発生や散発的な患者発生の報告がある。

［柳下徳雄］

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