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  3. Researchers say extra vitamin E fed to turkeys appears to help control infections from listeria(李氏杆菌). People who eat foods that

Researchers say extra vitamin E fed to turkeys appears to help control infections from listeria(李氏杆菌). People who eat foods that

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问题     Researchers say extra vitamin E fed to turkeys appears to help control infections from listeria(李氏杆菌). People who eat foods that contain this bacteria can get listeriosis(李氏杆菌病).
    This disease is especially dangerous to pregnant women, newborn babies and people with weakened defenses. The United States has more than two thousand cases of listeriosis each year and five hundred people die of it. Some cases have been linked to poultry(家禽)products that have not been cooked enough. The researchers found that vitamin E improved the ability of turkeys to fight the growth of listeria. The findings could help other meat industries as well.
    Irene Wesley led the study for the United States Department of Agriculture. Researchers from Iowa State University and the University of Arkansas also took part. The findings appeared in Poultry Science magazine earlier this year.
    Vitamin E is found in oils from vegetables, grains and animals. It helps protect some kinds of fatty acids that are necessary for healthy cells. Vitamin E helps prevent oxygen from combining with these fats to cause damage to cells.
    Turkeys need vitamin E for normal development. But the scientists added extra amounts to the diet of two groups of turkeys. The birds were one day old. Two other groups were not given any extra vitamin E. After six weeks, the researchers infected all the young turkeys with listeria. The scientists then tested the birds for the presence of the bacteria over a period of time.
    The results showed that the birds that received extra vitamin E did not get infected as often as the others. The birds that received the largest amount had the lowest number of infections.
    The scientists say vitamin E has a similar effect on chickens. They say chickens and turkeys that receive added vitamin E develop more infection-fighting cells called lymphocytes. The increased number of these cells appears to also help protect against other diseases that can be carried by birds.
    The scientists continue tests. They want to see if vitamin E can stop other dangerous bacteria that can enter food. They are testing it against salmonella and Campylobacter.
The disease caused by listeria______.
选项 A、is linked to poultry products cooked enough
B、is especially dangerous not only to newborn babies but also to people with weakened defenses
C、is not dangerous
D、is dangerous only to pregnant women and newborn babies
答案B
解析 细节题。根据短文第二段第一句This disease is especially dangerous topregnant women，newborn babies and people with weakened defenses．可知，李氏杆菌病对孕妇、新生婴儿以及抵抗力差的人都有很大的危害。故答案为B。
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