Reading Comprehension

Folks the below question looks easy but took me for a ride. Can someone pls. clarify the way i understood from passage.

"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 provided lifelong immunity without paralysis.
Thus, the hygiene that helped prevent typhoid epidemics
indirectly fostered a paralytic polio epidemic."

1. 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


I understood like below:
a. Poliomyelitis occurred in 20th century and modern sanitation helped to delay exposure to polio until adult hood or adolescence.
b.Without sanitation polio used to occur in infancy.

I didn't understand the last statement:
"Thus, the hygiene that helped prevent typhoid epidemics
indirectly fostered a paralytic polio epidemic."

What makes author to tell "Typhoid epidemics" -> "paralytic polio epidemics"? I didn't understand this and i selected D. The answer is C.

Can someone pls. explain me why even E is not correct.
What i understood is "Without sanitation" polio used to occur in Infancy and with some sanitation it delays until adulthood. Even if polio is delayed until adulthood still the adults are going to get polio by lack of sanitation.

Modern sanitation --- > delay polio exposure --- > adulthood paralysis

That means bcoz of sanitation the people who might have had polio as infant got a delay in exposure and then in adulthood they had paralysis bcoz of polio infectiion.


the hygiene that helped prevent typhoid epidemics
indirectly fostered a paralytic polio epidemic.

This statement says that the hygiene that resulted in delay in polio infection and caused paralysis in adults but it helped to curb the infection of typhoid and avoid an epidemic due to typhoid.

Sanity ---> causes ---> paralysis in adults
Sanity ---> avoids ---> typhoid

So if sanity was absent dedfinately a typhoid epidemic could have occured.

Hope that helps.

I figured out the relation between typhoid and polio in first attempt itselt but chose D as I felt this is more closely attached to the question. In the passage, I thought the contrast between the pre and post modern sanitation would help us answer the question.

Can some one add something from this point of view?

AIM GMAT wrote:Modern sanitation --- > delay polio exposure --- > adulthood paralysis

That means bcoz of sanitation the people who might have had polio as infant got a delay in exposure and then in adulthood they had paralysis bcoz of polio infectiion.


the hygiene that helped prevent typhoid epidemics
indirectly fostered a paralytic polio epidemic.

This statement says that the hygiene that resulted in delay in polio infection and caused paralysis in adults but it helped to curb the infection of typhoid and avoid an epidemic due to typhoid.

Sanity ---> causes ---> paralysis in adults
Sanity ---> avoids ---> typhoid

So if sanity was absent dedfinately a typhoid epidemic could have occured.

Hope that helps.

D: An epidemic of paralytic polio among infants


D is definately wrong , it mentions about paralytic polio in infants , whereas the argument mentions that in infants polio occurs without paralysis and in adults it produces paralysis.

"D is definately wrong , it mentions about paralytic polio in infants , whereas the argument mentions that in infants polio occurs without paralysis and in adults it produces paralysis."


Sorry guys i am still confused with E(below). From above E should still be correct?

E: An epidemic of paralytic polio among adolescents and adults