The Nobel Assembly at Karolinska Institutet has today decided to award
the 2015 Nobel Prize in Physiology or Medicine
with one half jointly to
William C. Campbell and Satoshi Ōmura
for their discoveries concerning a novel[新奇;异常的]therapy against infections[传染病;感染] caused by roundworm[蛔虫] parasites[寄生虫]
and the other half to
Youyou Tu
for her discoveries concerning a novel therapy against Malaria[疟疾]

Diseases caused by parasites[寄生虫] have plagued[困扰;折磨] humankind for millennia[千年期;一千年] and constitute[组成,构成;建立;任命] a major global health problem. In particular, parasitic diseases[寄生虫病] affect the world’s poorest populations[最贫困人口] and represent a huge barrier to improving human health and wellbeing. This year’s Nobel Laureates[获奖者] have developed therapies that have revolutionized[彻底改革] the treatment of some of the most devastating[毁灭性的;全然的] parasitic diseases.

William C. Campbell and Satoshi Ōmura discovered a new drug, Avermectin[阿维菌素], the derivatives[派生物] of which have radically[根本上;彻底地;以激进的方式] lowered the incidence[发生率;影响] of River Blindness[河盲;盘尾丝虫病] and Lymphatic Filariasis[淋巴丝虫病,丝虫病], as well as showing efficacy[功效,效力] against an expanding number of other parasitic diseases. Youyou Tu discovered Artemisinin[青蒿素], a drug that has significantly reduced the mortality rates[死亡数，死亡率] for patients suffering from Malaria[疟疾；瘴气].

These two discoveries have provided humankind with powerful new means to combat[战斗；搏斗] these debilitating[使衰弱的] diseases that affect hundreds of millions of people annually. The consequences in terms of improved human health and reduced suffering are immeasurable[无限的;不可计量的].

Parasites cause devastating diseases

We live in a biologically[生物学上，生物学地] complex world, which is populated not only by humans and other large animals, but also by a plethora[过多的] of other organisms[生物体], some of which are harmful or deadly to us.

A variety of parasites[寄生虫;寄生生物] cause disease. A medically[医学上地；医药上地] important group are the parasitic worms[寄生虫] (helminths[蠕虫肠虫；寄生虫]), which are estimated to afflict[折磨；使痛苦；使苦恼] one third of the world’s population and are particularly prevalent[流行的；普遍的，广传的] in subSaharan Africa[撒哈拉沙漠以南的非洲], South Asia[南亚] and Central and South America. River Blindness and Lymphatic Filariasis are two diseases caused by parasitic worms. As the name implies, River Blindness (Onchocerciasis[盘尾丝虫病]) ultimately leads to blindness, because of chronic inflammation[慢性炎症] in the cornea[角膜]. Lymphatic Filariasis, afflicting more than 100 million people, causes chronic swelling[慢性肿胀] and leads to life-long stigmatizing[红斑] and disabling clinical symptoms[临床症状；临床特征], including Elephantiasis[象皮病] (Lymphedema[淋巴水肿]) and Scrotal Hydrocele[阴囊鞘膜积液].

Malaria[疟疾;瘴气] has been with humankind for as long as we know. It is a mosquito-borne[蚊虫传播的] disease caused by single-cell parasites[单细胞寄生生物], which invade[侵略;侵袭;侵扰;涌入] red blood cells[红细胞], causing fever, and in severe cases brain damage[脑损伤] and death. More than 3.4 billion of the world’s most vulnerable citizens are at risk of contracting[染 (重病)] Malaria, and each year it claims more than 450 000 lives, predominantly[主要地；显著地] among children.

From bacteria and plants to novel anti-parasite therapies

After decades of limited progress in developing durable[耐用;持久] therapies for parasitic diseases, the discoveries by this year’s Laureates[获奖者] radically[根本上;彻底地] changed the situation.

Satoshi Ōmura, a Japanese microbiologist[微生物学家] and expert in isolating natural products[分离天然产物], focused on a group of bacteria, Streptomyces[链霉菌属], which lives in the soil and was known to produce a plethora[过多；过剩] of agents[药剂] with antibacterial activities[抗菌活性] (including Streptomycin[链霉素] discovered by Selman Waksman, Nobel Prize 1952). Equipped with extraordinary skills in developing unique methods for large-scale culturing[培植；开化] and characterization of[表征] these bacteria, Ōmura isolated new strains[菌株] of Streptomyces[链霉菌属] from soil samples[土壤样本] and successfully cultured them in the laboratory. From many thousand different cultures[一组培养菌; 一组培养细胞], he selected about 50 of the most promising, with the intent that they would be further analyzed for their activity[活性] against harmful microorganisms[微生物，微生虫].

William C. Campbell, an expert in parasite biology[寄生虫生物学] working in the USA, acquired Ōmura’s Streptomyces[链霉菌属] cultures and explored their efficacy. Campbell showed that a component[成分] from one of the cultures was remarkably efficient against parasites in domestic and farm animals[家畜]. The bioactive agent[生物活性剂] was purified[净化的；精制的] and named Avermectin[阿维菌素], which was subsequently[随后，其后；后来] chemically modified to a more effective compound[化合物] called Ivermectin[伊佛霉素]. Ivermectin was later tested in humans with parasitic infections[寄生虫感染] and effectively killed parasite larvae[幼虫；幼体] (microfilaria[微丝蚴]). Collectively[共同地，全体地], Ōmura and Campbell’s contributions led to the discovery of a new class of drugs with extraordinary efficacy[非凡的功效] against parasitic diseases.

Malaria[疟疾;瘴气] was traditionally treated by chloroquine[氯喹（疟疾特效药的一种）] or quinine[奎宁；金鸡纳碱], but with declining success. By the late 1960s, efforts to eradicate[根除，根绝；消灭] Malaria had failed and the disease was on the rise. At that time, Youyou Tu in China turned to traditional herbal medicine[草药医学，草药] to tackle the challenge of developing novel Malaria therapies. From a large-scale screen of herbal remedies[草药] in Malaria-infected animals, an extract from the plant Artemisia annua[黄花蒿] emerged as an interesting candidate. However, the results were inconsistent[不一致的；前后矛盾的], so Tu revisited the ancient literature[古代文献] and discovered clues[发现线索] that guided her in her quest to[寻找] successfully extract[提取；取出] the active component from Artemisia annua. Tu was the first to show that this component, later called Artemisinin[青蒿素], was highly effective against the Malaria parasite, both in infected animals and in humans. Artemisinin represents a new class of antimalarial agents[抗疟剂;药物] that rapidly kill the Malaria parasites at an early stage of their development, which explains its unprecedented[空前的；无前例的] potency[效能；力量] in the treatment of severe Malaria.

Avermectin, Artemisinin and global health

The discoveries of Avermectin[阿维菌素] and Artemisinin[青蒿素] have fundamentally changed the treatment of parasitic diseases. Today the Avermectin-derivative[衍生物，派生物] Ivermectin[伊佛霉素] is used in all parts of the world that are plagued[困扰;折磨] by parasitic diseases. Ivermectin[伊佛霉素] is highly effective against a range of parasites, has limited side effects[副作用] and is freely available across the globe. The importance of Ivermectin for improving the health and wellbeing of millions of individuals with River Blindness and Lymphatic Filariasis, primarily in the poorest regions of the world, is immeasurable. Treatment is so successful that these diseases are on the verge of[濒临于；接近于] eradication[消灭，扑灭；根除], which would be a major feat[壮举] in the medical history of humankind. Malaria infects[疟疾感染] close to 200 million individuals yearly. Artemisinin is used in all Malaria-ridden[为…所困扰的] parts of the world. When used in combination therapy[联合治疗], it is estimated to reduce mortality from Malaria by more than 20% overall and by more than 30% in children. For Africa alone, this means that more than 100 000 lives are saved each year.

The discoveries of Avermectin and Artemisinin have revolutionized therapy for patients suffering from devastating parasitic diseases. Campbell, Ōmura and Tu have transformed the treatment of parasitic diseases. The global impact of their discoveries and the resulting benefit to mankind are immeasurable.

来源：诺贝尔奖官网

http://www.nobelprize.org/nobel_prizes/medicine/laureates/2015/press.pdf