[by:www.51voa.com] [00:00.00]¸ü¶àÌýÁ¦Çë·ÃÎÊ51VOA.COM [00:00.00]Researchers in Ireland and England [00:02.76]may have discovered a new way to fight roundworm parasites. [00:08.22]The researchers say they identified a method [00:11.85]that could possibly turn an animal at risk for the disease [00:16.24]into one that can fight the infection. [00:20.34]Their findings were published in PLOS, the Public Library of Science. [00:27.24]More than 800 million people around the world are infected with the parasite. [00:35.08]The highest infection rates are in parts of Asia, [00:38.42]south-central Latin America and Africa, south of the Sahara. [00:44.82]The World Health Organization says roundworm [00:49.03]is one of many neglected diseases in warm climates. [00:53.99]In other words, not much research is being done to stop these diseases. [01:01.93]Roundworm is the most common of three diseases transmitted through soil. [01:09.79]Most humans infected with roundworm do not show signs of the disease. [01:17.32]People only realize they are infected [01:21.60]after the parasite leaves the body in the person's waste or vomit. [01:28.29]Fertilized roundworm eggs are left in the soil from human waste. [01:35.66]When the eggs enter the body, they hatch in the intestine. [01:41.22]The roundworm larvae then move into the liver where they grow larger. [01:48.80]They then travel through the bloodstream into the lungs. [01:54.33]After a few days, the worms leave the lungs and enter the throat, [02:01.12]where they are either swallowed or expelled from the body. [02:06.87]If they return to the intestines, [02:09.51]the female worms can produce up to 200,000 eggs a day. [02:15.91]The eggs are deposited into the soil when a person defecates. [02:22.10]This restarts the cycle of infection. [02:26.54]Roundworms can be especially harmful to children. [02:31.64]Adult worms can live in the body for up to two years, blocking the intestines. [02:40.44]The larvae can also cause breathing problems when they enter the lungs. [02:47.31]The WHO fights the parasite by "deworming" people [02:53.92]who live in areas with high rates of infection. [02:58.46]Patients are given strong medicines designed to kill the parasites. [03:04.42]Graham Medley is a professor of Infectious Disease Modelling [03:10.19]at the London School of Hygiene and Tropical Medicine. [03:14.69]He noted that deworming is effective [03:19.00]at stopping the disease from spreading, [03:21.82]but it does not end the health threat. [03:25.94]His comments were published in the British medical journal The Lancet. [03:31.90]Medley told VOA that "roundworms [03:36.92]are a major public health problem in low-income countries, [03:41.70]and having a drug that prevents infection would be a major advance." [03:48.46]Researchers have found that some people [03:52.17]are more likely to be infected with roundworm than others. [03:57.08]But it is costly to study humans, [04:00.97]so researchers use mice that have the same chance of being infected. [04:07.84]When these animals are infected, [04:11.21]a larger number of the parasites enter their lungs [04:15.79]than enter those of mice that are resistant to the parasites. [04:21.82]Earlier research suggested that the livers [04:26.16]of these two genetically-different mice must be different. [04:31.49]Jim Carolan works at Maynooth University in Ireland. [04:37.18]He told VOA that humans should be able [04:42.20]to stop the parasite from entering our bodies. [04:46.64]"But it doesn't," he said, "because the [roundworms] [04:50.14]have evolved ways to evade or suppress the system." [04:56.28]Carolan wanted to learn how the organisms did that. [05:01.16]So he studied the liver proteins of the two genetically-different mice. [05:07.20]He and his team found that the liver cells of resistant mice [05:13.78]had more copies of a protein than the mice that were more likely to be infected. [05:21.09]The proteins create a chemical which the researchers [05:25.53]believe could be toxic to the parasitic cells. [05:30.08]But they are not sure. [05:32.35]Carolan notes that more research must be done [05:36.14]before drugs can be developed and tested on humans. [05:40.58]But he said the research is "pointing us [05:44.24]in a direction that we need to focus on." [05:47.79]I'm Christopher Jones-Cruise.