OG20-119

seuhongkai

20-119

Scientists have discovered the importance of social and ecological factors to epidemics. Polimyelitis, for example, emerged as an epidemic in the United States in the twentieth centry; by then moder sanitation was able to delay exposure to polio untill adolescence or adulthood, at which time polio infection produced paralysis.  Previously, infection had occured during infancy, when it typically provided lifelong immunity without paralysis. Thus the hygiene that helped prevent typhoid epidemics indirectly fostered a  paralytic polio epidemic.

119. The passage suggests that a lack of modern sanitation would make which of the following most likely to occur?

C an epidemic of typhoid

D an epidemic of paralytic polio among infants

E an epidemic of paralytic polio amnong adolesents and adults.

the answer is C.

根据前面的话可以看出，后面P的例子是用来支持社会和生态因素对EPIDEMIC有影响的。但是这个例子，我不太理解。怎么忽然从BECAUSE句里蹦出来个T EPIDEMIC? 最后一句说现代医学对T和防治导致了P的发生，怎么导致的？前面并没有表明二者有什么联系啊？

选项C其实并没有什么不对，但是很容易被忽略，因为此例看上去是针对P的。所以直观的判断应该是关于P的。但是可能是因为DE不对吧，但是为啥呢？

susander

moder sanitation was able to delay exposure to polio untill adolescence or adulthood, at which time  ...
msufcufou 发表于 2010-9-24 08:39

    个人理解：现代的医疗卫生设施可以有效的防治polio在infancy时的感染，所以，人们现在是会在成年的时候感染polio，而成年才感染polio在原有的症状基础上还会出现paralysis

reddragon

回答此题还是从原文出发。
Thus the hygiene that helped prevent typhoid epidemics indirectly fostered a  paralytic polio epidemic.--->hygiene prevented typhoid epidemics.
如果没有了hygiene ，那么typhoid epidemics就会occur.

jianglxiang

个人认为需要关注修饰词paralytic（致瘫的）的限定。首先明确在infants中的病不会导致paralytic，而且能够产生免疫，也就是不会到了成年的时候再感染从而致瘫。所以DE肯定是错的，因为没有现代医学，人们在婴儿的时候已经患病，而不会成年后患病，排除E。而在infancy阶段是without paralysis的

msufcufou

moder sanitation was able to delay exposure to polio untill adolescence or adulthood, at which time polio infection produced paralysis.

那这句话是指什么的？谢谢

jingjane222

看来，还是要关注原文细节的啊。

parispings

回答此题还是从原文出发。
Thus the hygiene that helped prevent typhoid epidemics indirectly fostered a  paralytic polio epidemic.--->hygiene prevented typhoid epidemics.
如果没有了hygiene ，那么typhoid epidemics就会occur.

xiaoxiangxixi

(D) because the context mentions: Previously, infection had occured during infancy, when it typically provided lifelong immunity without paralysis. As a result, (D) won't be correct.

also, according the above condition, the infants already got the immunity. then the adults and adolescents won't get the epidemic either.