From VOA Learning English, this is the Health Report. 这里是美国之音慢速英语健康报道。

Scientists are working on ways to stop a disease that threatens one-fifth of the world's population. Over 120 million people are infected with lymphatic filariasis, also known as elephantiasis. The disease is found mainly in Southeast Asia and Africa. It effects the lymphatic system which is a major part of the body's natural defense for fighting disease. 科学家们正在研究如何消除威胁世界1/5人口的一种疾病。超过1.2亿人感染了淋巴丝虫病，它也被称为象皮病。这种病主要分布在东南亚和非洲，它能影响淋巴系统，这是人体对抗疾病的天然防线的一个重要组成部分。

Elephantiasis can cause swelling or enlargement of skin and tissue. The cause is a tiny worm that enters and lives in lymphatic tubes for six to eight years. 象皮病能够引起皮肤或组织肿胀。其病因是一种微小的蠕虫进入到淋巴管并存活6到8年。

Scientists say they have been able to demonstrate that the most common cause of elephantiasis can be stopped. They are urging those at risk to sleep under nets treated with chemicals that kill a common insect - the mosquitoes. 科学家们表示，他们已经能够证明象皮病最常见的病因能够被消除。他们正督促处于感染危险中的人们睡在经过杀灭蚊虫的化学物质处理过的蚊帐里。

Lisa Reimer teaches at the Liverpool School of Tropical Medicine. She formerly served in Papua New Guinea, as part of the team studying the disease. The team involved researchers from Papua New Guinea, Britain, Australia and the United States. 莉萨·雷默在利物浦热带医学院任教。她曾作为研究该病的团队的成员任职于巴布亚新几内亚。该团队包含了来自巴布亚新几内亚、英国、澳大利亚和美国的研究人员。

Doctor Reimer says she was surprised at how effective anti-malaria bed nets covered with insecticide could be at fighting the disease. 雷默博士说，她对杀虫剂处理过的防疟疾蚊帐能够有效对抗该疾病表示非常惊讶。

"Filariasis is only picked up by mosquitoes late in the evening, so this is the time when people are more likely to be protected by their bed nets. So we found that bed net use actually is a greater barrier against filariasis transmission whereas malaria transmission may still be occurring outside the times when the user is under the net." 她说，“丝虫病只会由深夜的蚊子携带，这是一个人们很可能受到了蚊帐保护的时间。所以我们发现，使用蚊帐实际上是防止丝虫病传播的一个重大屏障，然而疟疾传播还是可能会在人们未在蚊帐里的其它时间发生。”

Doctors normally use drugs to fight the disease. Ms Reimer says doctors in Papua New Guinea gave the drugs to people of five villages. She says this treatment nearly ended the threat from the worm to humans, but the drugs didn't stop the threat from mosquitoes. 医生们通常使用药物来对抗这种疾病。雷默女士说，巴布亚新几内亚的医生们把药物发给了5个村庄的人们。她说，这种处置办法近乎消除了这种蠕虫对人类的威胁，但这种药物未能消除来自蚊虫的威胁。

The treated nets block female mosquitoes from securing blood, which is necessary for them to reproduce. The insecticide also cuts the life of the insects in half. 处理过的蚊帐可以防止雌性蚊子吸血，这是它们繁殖的必要条件。杀虫剂也将这些蚊虫的寿命缩减了一半。

"If we can reduce mosquito-biting rates then we're able to increase the thresholds below which the disease prevalence will move to zero. So by controlling mosquitoes we're making the targets for the mass drug administration more obtainable." 她说，“如果我们能够降低蚊虫叮咬率，我们就能提高阙值，使该病的患病率降低到零。因此通过控制蚊虫，我们就能使得大规模药物治疗的目标更容易实现。”

The World Health Organization (WHO) has set a goal of stopping lymphatic filariasis as a public health problem by the year 2020. 世界卫生组织已经设定了一个目标，在2020年前将淋巴丝虫病作为一个公共卫生问题予以消除。

The WHO estimates that 1.4 billion people in 73 countries are at risk of the disease. children are often infected, but they do not show signs of the disease until later in life. 世界卫生组织预计，73个国家的14亿人处于该病的风险中。儿童往往被感染，但直到以后才会显现出感染该病的征兆。