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Wonderful worms

发布时间:2019-03-07 01:11:07来源:未知点击:

By Andy Coghlan REGULAR doses of worms might rid people of inflammatory bowel disease, say researchers in Iowa. They believe this distressing condition, which is increasingly common in the developed world, is caused by the absence of intestinal parasites. “We’re living in sterile boxes, breathing sterile air and drinking sterile water,” says Joel Weinstock, who led the research. Weinstock and his colleagues at the University of Iowa have already fed six sufferers eggs that hatched and developed into parasitic worms. The results were so dramatic that they are planning a larger trial this autumn. “Between the second and third week after treatment, five of the six patients went into complete remission,” says Weinstock. A single dose of worms eased symptoms for about a month. Inflammatory bowel disease—an umbrella term for ulcerative colitis and Crohn’s disease—appears to be caused by an overactive immune system. Symptoms include diarrhoea, abdominal pain, bowel obstruction and bleeding. Weinstock noticed that the rise in inflammatory bowel disease was preceded by a decline in intestinal worm infections. Seventy years ago, he says, 40 per cent of American children had worms such as Ascaris lumbricoides, which grow up to 20 centimetres long. As recently as the 1940s, many were infected with smaller whipworms (Trichuris trichuria). “By the 1960s, kids no longer had it,” says Weinstock. “The worms living in the gastrointestinal tract have been with us for 3 million years or longer,” he says. “Our immune systems have grown used to their presence.” And without such parasites, Weinstock believes the immune system is more likely to produce powerful inflammatory agents such as gamma-interferon, which fire up the activity of white blood cells called macrophages. “As we’ve de-wormed, people have developed immune systems which are not damped,” he says. The six patients in the initial trial were chosen because steroids and other drugs designed to dampen down the immune system had not helped. Working with his colleagues David Elliott and Robert Summers, Weinstock gave each patient a drink containing microscopic eggs of a species of intestinal worm that doesn’t normally infect people. Although these worms can survive in the human gut, growing to about 1 centimetre, they cannot reproduce and are eliminated after a couple of months. Balfour Sartor, an expert on inflammatory bowel disease at the University of North Carolina in Chapel Hill, is intrigued by Weinstock’s experiment. “It’s an appealing way of using something that’s of fairly low toxicity to treat a set of diseases that for now we don’t have a cure for,” he says. Sartor is himself experimenting with Lactobacillusand Bifidobacterium gut bacteria, again with the idea that they may have dampening effects on the immune system. However,