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  3. For more than 50 years, microbiologists in the U.S. and Europe have warned ag

For more than 50 years, microbiologists in the U.S. and Europe have warned ag

游客2023-12-26  20
问题    For more than 50 years, microbiologists in the U.S. and Europe have warned against using antibiotics to fatten up farm animals. The practice, they argue, threatens human health by turning farms into breeding grounds of drug-resistant bacteria. Farmers responded that restricting antibiotics in livestock would devastate the industry and significantly raise costs to consumers. We have empirical data that should resolve this debate. Since 1995, Denmark has enforced progressively tighter rules on the use of antibiotics in raising pigs, poultry and other livestock. In the process, it has shown that it’s possible to protect human health without hurting farmers.
   Farmers in many countries use antibiotics in two key ways: (1) at full strength to treat sick animals and (2) in low doses to fatten meat-producing livestock or to prevent veterinary illnesses. Although even the proper use of antibiotics can inadvertently lead to the spread of drug-resistant bacteria, the habit of using a low or "sub-therapeutic" dose is a formula for disaster: the treatment provides just enough antibiotic to kill some but not all bacteria. The germs that survive are typically those that happen to bear genetic mutations for resisting the antibiotic. They then reproduce and exchange genes with other microbial resisters. Because bacteria are found literally everywhere, resistant strains produced in animals eventually find their way into people as well. You could hardly design a better system for guaranteeing the spread of antibiotic resistance.
   The data from multiple studies over the years support the conclusion that low doses of antibiotics in animals increase the number of drug-resistant microbes in both animals and people. As Joshua M. Scharfstein, a principal deputy commissioner at the Food and Drug Administration, put it, "You actually can trace the specific bacteria around and ... find that the resistant strains in humans match the resistant strains in the animals." And this science is what led Denmark to stop sub-therapeutic dosing of chickens, pigs and other farm animals.
   Although the transition unfolded smoothly in the poultry industry, the average weight of pigs fell in the first year. But after Danish farmers started leaving piglets together with their mothers a few weeks longer to bolster their immune systems naturally, the animals’ weights jumped back up, and the number of pigs per litter increased as well. The lesson is that improving animal husbandry — making sure that stalls and cages are properly cleaned and giving animals more room or time to mature — offsets the initial negative impact of limiting antibiotic use. Today Danish industry reports that productivity is higher than before. Meanwhile, reports of antibiotic resistance in Danish people are mixed, which shows — as if we needed reminding — that there are no quick fixes.
   Of course, the way veterinary antibiotics are used is not the only cause of human drug-resistant infections. Careless use of the drugs in people also contributes to the problem. But agricultural use is still a major contributing factor. Every day brings new evidence that we are in danger of losing effective antibiotic protection against many of the most dangerous bacteria that cause human illness. The technical issues are solvable. Denmark’s example proves that it is possible to cut antibiotic use on farms without triggering financial disaster. In fact, it might provide a competitive advantage. Stronger measures to deprive drug-resistant bacteria of their agricultural breeding grounds simply make scientific, economic and common sense. [br] We can infer from Paragraph 3______.
选项 A、Denmark has stopped using any antibiotics in animals
B、low dose of antibiotics has little effect on human health
C、drug-resistant bacteria in animals can spread to humans
D、humans and farm animals have similar bacteria structure
答案 C
解析 推断题。第3段第1句说有数据表明在动物身上使用低剂量抗生素会同时增加动物体内和人体内抗药性细菌的数量。第2句引用约书亚的结论，通过追踪“发现人体内的耐药菌种与动物体内的耐药菌种是一致的”。可以推出答案为C(动物体内耐药细菌会转嫁给人类)。需注意的是match是“相同，一致”的意思，不同于similar“类似”的意思，考生易误选D。
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