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One of the most important organizations designed to combat fatal infectious diseases in poor countries goes by the unwieldy name

admin2013-07-02  51
问题     One of the most important organizations designed to combat fatal infectious diseases in poor countries goes by the unwieldy name of the Global Fund to Fight AIDS, Tuberculosis and Malaria. The link between the first two is well established. AIDS does not kill directly. Rather, the damage it does to the immune system opens an individual to other infections that would frequently be fought off by a healthy body. Of these, tuberculosis is one of the most important. Some 12% of deaths of people infected with HIV, the virus mat causes AIDS, are from tuberculosis, and, conversely, 16% of tuberculosis deaths are AIDS-related. The disease of malaria kills a lot of people — at least 1 million a year, although the exact figure is hard to come by — but there was little obvious medical connection between it and the other two.

    No longer. Over the past few years a number of studies have suggested mat those who are infected with HIV are more susceptible to malaria, and that the malaria parasite, in turn, raises the number of virus particles in those with HIV. Now, a study published in Science by Laith Abu-Raddad of the University of Washington, in Seattle, and his colleagues has tried to put some numbers on the problems.
    The study’s starting point is that the number of virus particles in the blood of someone infected with HIV increases about ten-fold during an attack of malaria. This seems to be due, paradoxically, to the immune system’s response to the malarial parasite. That response produces proteins called cytokines, which have the perverse effect of encouraging HIV to replicate.
    The increase in the number of virus particles is transient, and may do little harm to the individual’s own long-term prospects, but it does make him(or her)more likely to pass the infection on during sex. Conversely, the damage HIV does to the immune system means that the malarial parasite can more easily breed unchecked. That means people are more susceptible to infection in the first place, and that more parasites are available to be transmitted from person to person by the mosquitoes that spread them.     Dr. Abu-Raddad and his colleagues looked at past studies and came up with a set of numbers that can be plugged into a mathematical model they have developed of how, based on other papers, they think the diseases interact. They then applied the model to Kisumu, a part of Kenya that has a high prevalence of both diseases.
    The model suggests the peak of the HIV epidemic in Kisumu is 8% higher than what it would have been if there were no interaction between the diseases, while the peak level of malaria is 13% higher. Moreover, and in contrast to tuberculosis, where the peak lags seven years behind that of HIV, malaria peaked only one year after the peak of the HIV epidemic.
What can we know from the first paragraph?
选项 A、AIDS is the direct cause that leads to people’s death.
B、Individuals infected AIDS can’t fight off other viruses normally.
C、Those who catch tuberculosis have a high possibility of HIV infection.
D、AIDS is often caused by tuberculosis virus.
答案B
解析 事实细节题。第一段中提到：患有艾滋病的个体易于感染其他疾病，而健康人体通常可以抵御这些疾病，这就说明了患有艾滋病的人不能正常地(nor—mally)抵御这些疾病，故选项[B]正确。[A]与事实相反，艾滋病并不直接使人丧命；[C]在文中没有提及；原文只是说肺结核是息艾滋病的人容易感染的疾病，故[D]错误。
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