[ti:Treated Bed Nets Critical to Stopping lymphatic Filariasis] [ar:Bob Doughty] [al:Health Report] [by:www.51voa.com] [00:00.00]From VOA Learning English, [00:03.25]this is the Health Report. [00:05.29]Scientists are working on ways to [00:09.22]stop a disease [00:11.06]that threatens one-fifth of the world's population. [00:15.05]Over 120 million people [00:19.53]are infected with lymphatic filariasis, [00:23.46]also known as elephantiasis. [00:27.06]The disease is found mainly in Southeast Asia and Africa. [00:33.24]It effects the lymphatic system [00:37.13]which is a major part [00:39.37]of the body's natural defense for fighting disease. [00:44.00]Elephantiasis can cause swelling [00:48.50]or enlargement of skin and tissue. [00:52.33]The cause is a tiny worm [00:56.26]that enters and lives in lymphatic tubes [01:00.15]for six to eight years. [01:02.59]Scientists say [01:05.03]they have been able to demonstrate [01:07.87]that the most common cause of elephantiasis [01:11.91]can be stopped. [01:13.50]They are urging those at risk [01:16.98]to sleep under nets [01:19.47]treated with chemicals [01:21.06]that kill a common insect - the mosquitoes. [01:25.20]Lisa Reimer teaches at the Liverpool School [01:29.93]of Tropical Medicine. [01:31.87]She formerly served in Papua New Guinea, [01:35.86]as part of the team studying the disease. [01:40.29]The team involved researchers from Papua New Guinea, [01:44.93]Britain, Australia and the United States. [01:49.46]Doctor Reimer says [01:52.31]she was surprised at how effective [01:56.14]anti-malaria bed nets covered with insecticide [02:00.07]could be at fighting the disease. [02:03.07]"Filariasis is only picked up [02:04.96]by mosquitoes late in the evening, [02:06.70]so this is the time [02:08.34]when people are more likely to be protected [02:10.03]by their bed nets. [02:11.03]So we found that bed net use actually [02:12.53]is a greater barrier against [02:14.02]filariasis transmission [02:15.32]whereas malaria transmission may still be occurring [02:17.36]outside the times when the user is under the net." [02:20.14]Doctors normally use drugs to fight the disease. [02:24.04]Ms Reimer says doctors in Papua New Guinea [02:29.16]gave the drugs to people of five villages. [02:33.44]She says this treatment nearly ended [02:37.87]the threat from the worm to humans, [02:41.07]but the drugs didn't stop the threat from mosquitoes. [02:45.99]The treated nets [02:48.63]block female mosquitoes from securing blood, [02:52.62]which is necessary for them to reproduce. [02:56.65]The insecticide also cuts the life of the insects in half. [03:02.78]"If we can reduce mosquito-biting rates [03:05.47]then we're able to increase the thresholds [03:08.41]below which the disease prevalence will move to zero. [03:11.95]So by controlling mosquitoes we're making the targets [03:15.51]for the mass drug administration more obtainable." [03:17.86]The World Health Organization (WHO) has [03:20.30]set a goal of stopping lymphatic filariasis [03:24.93]as a public health problem by the year 2020. [03:29.71]The WHO estimates that 1.4 billion people [03:35.89]in 73 countries are at risk of the disease. [03:40.36]Children are often infected, [03:43.81]but they do not show signs of the disease [03:46.99]until later in life. [03:49.08]And that's the Health Report from VOA Learning English. [03:55.25]I'm Bob Doughty.