Although genetic mutations in bacteria and viruses ca n lead to epidemics，
some epidemics are caused by bacteria and viruses that have undergone no
significant genetic change．In analyzing the latter, scientists have
discovered the importance of social and ecological factors to epidemics．
Poliomyelitis，for example，emerged as an epidemic in the United States in
the twentieth century by then，modern sanitation was able to delay exposure
to polio Until adolescence or adulthood，at which time polio infection
produced paralysis． Previously, infection had occurred during infancy, when
it typically 9rovided lifelong immunity without paralysis．Thus，the hygiene
that helped prevent typhoid epidemics indirectly fostered a paralytic polio
epidemic. Another example is lyme disease， which is caused by bacteria that
are transmitted by deer ticks．It occurred only sporadically during the late
nineteenth century but has recently become prevalent in parts of the United
States，largely due to an increase in the deer population that occurred
simultaneously with the growth of the suburbs and increased outdoor
recreational activities in the deer's habitat．Similarly, an outbreak of
dengue hemorrhagic fever became an epidemic in Asia in the 1950's because of
ecological changes that caused Aedes aegypti，the mosquito that transmits the
dengue virus，to proliferate。The stage is now set in the United States for a
dengue epidemic because of the inadvertent introduction and wide
dissemination of another mosquito，Aedes albopictus．
6. The passage suggests that a lack of modern sanitation would make which of
the following most likely to occur?
(A) An outbreak of Lyme disease
(B) An outbreak of dengue hemorrhagic fever
(C) An epidemic of typhoid
(D) An epidemic of paralytic polio among infants
(E) An epidemic of paralytic polio among adolescents and adults
我想問E的選項哪裡錯?
因為我對於這句不是很懂
modern sanitation was able to delay exposure to polio Until adolescence or
adulthood，at which time polio infection produced paralysis．
Previously, infection had occurred during infancy, when it typically provided
lifelong immunity without paralysis
衛生條件延緩了小兒麻痺 一直到青少年時期
先感染小兒麻痺在嬰兒時期 之後就終生免疫
這2句到底在說什麼???
Thus, the hygiene that helped prevent typhoid epidemics indirectly fostered
a paralytic polio epidemic.
他就只是說因為預防流性性的衛生學間接培養了小兒麻痺
為什麼會這樣說間接哩??
可以解釋一下嗎
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 99.141.31.27