The Diabolical Genius of an Ancient Scourg


By Sally Lehrman S. レーマン
English 日本語 日本語
Today most people in the richer parts of the world think of tuberculosis, if they think of it at all, as a ghost of history. Throughout ancient times the tenacious bacterial infection consumed the bodies of untold millions, rich and poor, filling their lungs with bloody sputum. As TB spread in the centuries that followed, it continued to attack across economic and class lines, affecting both the famous and the obscure. Among its better-known victims: poet Manuel Bandeira, writers Emily and Anne Bronte, and sculptor Frederic-Auguste Bartholdi, who designed the Statue of Liberty. By the early 20th century humanity had begun fighting back with public health campaigns, improved living standards, and eventually antibiotics and a modestly effective vaccine. Although in 2011 TB sickened nearly nine million people, killing 1.4 million of them, mostly in the poorer regions of the globe, the mortality rate has nonetheless fallen by more than a third since 1990. Things are looking upーor so it may seem.  今日,世界の富裕な地域に住むほとんどの人々は,結核について考えることが仮にあったとしても,過去の亡霊くらいにしか思わない。この執拗な細菌感染症は,古代においては貧富を問わず何百万もの人の肺を血痰で埋め,命を奪った。その後も結核はどんどん広がり,貧富の差や階級の差を超えて,人々を攻撃し続けた。有名人も無名の人も結核の犠牲になった。名の知られた犠牲者には,詩人のマヌエル・バンデイラ,作家のエミリーとアンのブロンテ姉妹,自由の女神を設計したことで知られる彫刻家フレデリック・バルトルディらがいる。
New genetic research, however, suggests that the bacterium responsible for TB could be poised to emerge stronger and more deadly than ever beforeーand not just because some strains have become resistant to treatment with the standard set of antibiotics. A small but increasingly influential group of investigators believes that the microbe, Mycobacterium tuberculosis, may have evolved along an unexpected and particularly dangerous path. The scientists have discovered that TB can be divided into seven families of genetically related strains, at least one of which is surprisingly virulent, prone to drug resistance and especially well suited to spreading disease in our increasingly interconnected, densely populated world.  ところが新たな遺伝学研究によると,結核をもたらす細菌はかつてないほど強力で致死性の高いものになりつつあるようだ。一部の菌株が標準的な抗生物質に耐性を持つようになったから,というだけではない。一部の研究者は結核菌( Mycobacterium tuberculosis ) は予想外の極めて危険な道をたどって進化してきたようだと考えており,最近注目を集めつつある。
At the same time, researchers worry that current approaches to treatment and the sole, partially effective vaccine may actually be helping the bacterium to become more intractable. Clinicians have long known that incomplete treatment can produce antibiotic-resistant TB strains. Yet they are now realizing that even successful interventions can be problematic if they are better at weeding out the milder, slower-growing groups of TB microbes. This divergent effect would allow the more aggressive, faster-spreading bacterial families to establish a stronger foothold.  また同時に,現在行われている治療法と,部分的な効果しかない唯一のワクチンが,結核菌が難治性になるのを助長している恐れがあると危惧されている。不完全な治療によって抗生物質に耐性のある結核菌株が生じ得ることは以前から知られている。しかし最近,治療がたとえうまくいっても,それがかえって問題をもたらす可能性があることに,臨床医らが気づき始めた。毒性が低く,増殖が遅い結核菌株が治療によって一掃されてしまうと,より攻撃的で迅速に伝播する菌株が足場を固めることにつながりかねないのだ。