Although genetic mutations in bacteria and viruses can lead to epidemi

Question

Although genetic mutations in bacteria and viruses can 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 provided 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 .   1 
 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

2 
 2. According to the passage, the outbreak of dengue hemorrhagic fever in the 1950's occurred for which of the following reasons?

A The mosquito Aedes aegypti was newly introduced into Asia.
B The mosquito Aedes aegypti became more numerous.
C The mosquito Aedes albopictus became infected with the dengue virus.
D Individuals who would normally acquire immunity to the dengue virus as infants were not infected until later in life.
E More people began to visit and inhabit areas in which mosquitos live and breed.

3 
 3. It can be inferred from the passage that Lyme disease has become prevalent in parts of the United States because of which of the following?

A The inadvertent introduction of Lyme disease bacteria to the United States
B The inability of modern sanitation methods to eradicate Lyme disease bacteria
C A genetic mutation in Lyme disease bacteria that makes them more virulent
D The spread of Lyme disease bacteria from infected humans to noninfected humans
E An increase in the number of humans who encounter deer ticks

4 
 4. Which of the following can most reasonably be concluded about the mosquito Aedes albopictus on the basis of information given in the passage?

A It is native to the United States.
B It can proliferate only in Asia.
C It transmits the dengue virus.
D It caused an epidemic of dengue hemorrhagic fever in the 1950's.
E It replaced Aedes aegypti in Asia when ecological changes altered Aedes aegypti's habitat.

5 
 5. Which of the following best describes the organization of the passage?

A A paradox is stated, discussed and left unresolved.
B Two opposing explanations are presented, argued, and reconciled.
C A theory is proposed and is then followed by descriptions of three experiments that support the theory.
D A generalization is stated and is then followed by three instances that support the generalization.
E An argument is described and is then followed by three counterexamples that refute the argument.

6 
 6. Which of the following, if true, would most strengthen the author's assertion about the cause of the Lyme disease outbreak in the United States?

A The deer population was smaller in the late nineteenth century than in the mid-twentieth century.
B Interest in outdoor recreation began to grow in the late nineteenth century.
C In recent years the suburbs have stopped growing.
D Outdoor recreation enthusiasts routinely take measures to protect themselves against Lyme disease.
E Scientists have not yet developed a vaccine that can prevent Lyme disease.

GMATNinja · Accepted Answer

The passage tells us that there has been "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." We are also told that Lyme disease "occurred only sporadically during the late nineteenth century" and that it "has recently become prevalent in parts of the United States."

So we know that the deer population increased at the same time that the suburbs grew and that the people starting to spend more time outside in the deer's habitat. But what if the deer population DECREASED somewhat after the late nineteenth century and THEN increased with the growth of the suburbs? The passage tells us that the deer population increased  with the growth of the suburbs , but we cannot assume that it is now higher than it was in the late nineteenth century (the passage does not specifically tell us when the growth of the suburbs occurred).

Based solely on the information in the passage, it is  possible  that the deer population in the late nineteenth century was about the same as the recent deer population. (A) eliminates that possibility and thus strengthens the argument.

mbaiseasy · Answer

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

" Thus, the HYGIENE that helped PREVENT TYPHOID epidemics
indirectly fostered a paralytic polio epidemic " - Remove HYGIENE then we get the reverse of PREVENTING TYPHOID 
 
 ANSWER:  (C) An epidemic of typhoid

2. According to the passage, the outbreak of dengue hemorrhagic fever in the 1950's occurred for which of the following reasons?
 
 " an outbreak of dengue hemor-
rhagic fever became an epidemic in Asia in the 1950's
because of ecological changes that caused Aedes aegypti,
(25) the mosquito that transmits the dengue virus, to proliferate " - PROLIFERATE / INCREASE in NUMBER

ANSWER:  (B) The mosquito Aedes aegypti became more numerous.

3. It can be inferred from the passage that Lyme disease has become prevalent in parts of the United States because of which of the following?
 
  "increased outdoor recreational activities in the
deer's habitat" - MORE EXPOSURE TO DEER  
 
 ANSWER:  (E) An increase in the number of humans who encounter deer ticks

4. Which of the following can most reasonably be concluded about the mosquito Aedes albopictus on the basis of information given in the passage?

" 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 " - newly introduced... hence, not native to the US...

A It is native to the United States.  They are newly introduced. Hence, out! 
B It can proliferate only in Asia.  They can cause epidemics in US. Hence, out! 
 ANSWER:  (C) It transmits the dengue virus.
D It caused an epidemic of dengue hemorrhagic fever in the 1950's.  This is another breed of mosquito 
E It replaced Aedes aegypti in Asia when ecological changes altered Aedes aegypti's habitat.  not mentioned

5. Which of the following best describes the organization of the passage?

A A paradox is stated, discussed and left unresolved.   Contrasting views mentioned initially but the discussion did not revolve around that...  
B Two opposing explanations are presented, argued, and reconciled.  Two views introduced but the discussion did not revolve around that 
 
C A theory is proposed and is then followed by descriptions of three experiments that support the theory.   no such experiments mentioned

ANSWER:  (D) A generalization is stated and is then followed by three instances that support the generalization.

E An argument is described and is then followed by three counterexamples that refute the argument.   the examples are not use as counterexamples but just examples of epidemics without genetic evolution

6. Which of the following, if true, would most strengthen the author's assertion about the cause of the Lyme disease outbreak in the United States?

ANSWER:  (A) The deer population was smaller in the late nineteenth century than in the mid-twentieth century.
  If the deer population was just same as population to day, then the increase in population will be an invalid explanation for the Lyme disease. This eliminate that possibility.

mokura · Answer

i'm confused about question number 6 - the passage already states that the deer population was smaller in the past. choice a is merely re-stating this fact. strengthening should bring something out of scope into the picture. would love if anyone can explain here. thanks!

dentobizz · Answer

OE #1: Lines 14–15 show that typhoid epidemics were prevented by modern sanitation; therefore, typhoid might breakout in the absence of modern sanitation.

OE #2 : The lines 24–28 mention outbreak became an epidemic in Asia  because of ecological changes that caused Aedes aegypti, the mosquito that transmits the dengue virus, to proliferate

OE #3: To make an inference about Lyme disease, examine the discussion of Lyme disease in lines 16–24. As the deer population grows and as humans encroach on the deer habitat, more people encounter deer ticks and become infected with the disease.

OE #4 : An inference is drawn from stated information rather than explicitly stated. Aedes albopictus is mentioned in the final sentence of the passage, which says that this mosquito was inadvertently introduced into the United States and has spread widely. Author states that the stage is now set in the United States for a dengue epidemic. It is reasonable to infer that this mosquito can transmit the dengue virus.

OE #5 : Analyze the structure of the passage in order to answer a question about how the passage is organized. Three specific examples—Polio, Lyme disease, and Dengue hemorrhagic fever—are used to support a general statement

OE#6 : The author blames the recent prevalence of Lyme disease on the rise in the deer population and the growth of the suburbs, with people spending more time outside in the deer’s habitat. 
For question number 6--If you read the lines 15-12 and the OE " The author blames the recent prevalence of Lyme disease on the rise in the deer population and the growth of the suburbs, with people spending more time outside in the deer’s habitat." you will find that option A -  will strengthen the authors assertion

mallya12 · Answer

"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. "

Not able to understand clearly. Can someone explain the meaning

Not able to understand clearly. Can someone explain the meaning

AkshdeepS · Answer

Alright, let me help you with this:

Poliomyelitis, for example, emerged as an epidemic in the United States in the twentieth century  ( Poliomyelitis was already present in the U.S, but in the

20th century it emerged as an epidemic. Before that its presence may have been less severe) ; by then  (In the 20th century) , modern

sanitation was able to delay exposure to polio until adolescence or adulthood  (modern sanitation was good and because of which polio exposure was delayed

till adulthood) , at which time polio infection produced paralysis  (This means , if polio virus infects you in adulthood, then this can lead to paralysis)

. Previously  (Before this, when good sanitation facility was not there) , infection had occurred during infancy (this polio

infection used to occur in the childhood)  , when it  (the occurence of polio in childhood)  typically provided lifelong immunity without

paralysis  (means occurence of polio in childhood provided lifelong immunity against paralysis) . Thus, the hygiene that helped prevent typhoid

epidemics indirectly fostered a paralytic polio epidemic.  (Thus, modern hygiene that helped preventing typhoid, indirectly supported paralytic polio epidemic.

Because of more hygiene polio occurs only after adulthood and in adulthood polio infection produced paralysis. But this does not happen when polio occurs in childhood

because of non hygiene conditions)

Conclusion :

More hygiene , no typhoid , but polio infects in adulthood, and polio in adulthood leads to paralysis.

Less hygiene, typhoid, but polio infects in childhood, but no paralysis.

Hope this helps.

jawele · Answer

Hi

I have the same question. It seems that A is merely a paraphrase, and I would expect something slightly out of scope to lend more support for the argument.

Thanks

GMATNinja

tejanaraharisetti · Answer

5. Which of the following best describes the organization of the passage?

A A paradox is stated, discussed and left unresolved.
B Two opposing explanations are presented, argued, and reconciled.
C A theory is proposed and is then followed by descriptions of three experiments that support the theory.
D A generalization is stated and is then followed by three instances that support the generalization.
E An argument is described and is then followed by three counterexamples that refute the argument.

I can understand that D is a better option, but I cannot able to figure out why it is considered as a generalization. Can someone please explain it?

CrackverbalGMAT · Answer

Hi Teja

The "generalization" referred to in option (D) is the following sentence:

In analyzing the latter, scientists have discovered the  importance of social and ecological factors  to epidemics.

This makes a sweeping statement that "social and ecological factors" are important to epidemics caused by virus and bacteria that have not undergone any significant change.

The three examples that follow - polio, Lyme disease and dengue - serve as strengtheners to support this generalization. All of them focus on the "social and ecological factors" that have caused these three diseases respectively to become epidemics. Hence, option (D) best explains the organization of the passage.

Hope this helps.

adityaganjoo · Answer

GMATNinja  Although you have already explained what makes (A) right in Question 6, could you please explain what makes (B) wrong?

GMATNinja · Answer

Question 6 
 
The author asserts that "social and ecological factors" can lead to epidemics, and his/her discussion of Lyme disease is an example of this assertion.

According to the author, Lyme disease was "sporadic" in the late nineteenth century and has "recently become prevalent." The ecological factor that led to this increase was "an increase in the deer population," and the social factors that led to this increase are "the growth of the suburbs and increased outdoor recreational activities in the deer's habitat."

To answer question 6, we have to strengthen the argument that these social and ecological factors led to the increase in Lyme disease.

Hmm. The author tells us that increased outdoors activity is one reason why people get Lyme disease NOW, when they didn't get it so often in the late nineteenth century. (B) seems to undermine this reasoning -- if people actually WERE increasingly interested in outdoor recreation in the nineteenth century, then perhaps the author is wrong about this factor playing a role in the recent prevalence of Lyme disease.

If anything, (B) actually  weakens  the author's argument that outdoor activity can explain the increase in Lyme disease.

(B) is out for question 6.

I hope that helps!

Bobby333 · Answer

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 Why is the answer not D, in 20th century because of good hygiene polio which was paralytic only affected adults and not infants. So if good habits are not there then it might have affected infants to....right?

GMATNinja · Answer

The passage tells us that before modern sanitation, polio infection occurred during infancy, when it "provided lifelong immunity  without paralysis ." So basically, without modern sanitation, you might expect polio to infect infants, but not to cause paralysis.

Notice that (D) talks about an "epidemic of  paralytic  polio among infants." Since we wouldn't expect polio to cause paralysis in infants, (D) is incorrect.

I hope that helps!

agrasan · Answer

Hi experts  KarishmaB   GMATNinja   MartyMurray

In question-6, I am not very clear to eliminate option D "Outdoor recreation enthusiasts routinely take measures to protect themselves against Lyme disease."

My reasoning is: If these people routinely take measures for protection against Lyme disease then it increases my confidence that the outdoor recreation is somewhat responsible as a cause for Lyme disease outbreak.

Is it wrong because  "enthusiasts"  doesn't necessarily mean people who actually do these outdoor recreation activities?

Please let me know where I am faltering in my reasoning.

GMATNinja · Answer

Question 6 If outdoor recreation enthusiasts routinely take measures to protect themselves against Lyme disease, then we wouldn't expect those people to get Lyme disease! If the outdoor enthusiasts are protected, an increase in outdoor recreational activities should NOT cause a significant increase in Lyme disease, so (D) actually weakens the author's assertion. For more on #6, check out these two posts: https://gmatclub.com/forum/although-gen ... l#p2287273 https://gmatclub.com/forum/although-gen ... l#p2808120

VerbalBot · Answer

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Although genetic mutations in bacteria and viruses can lead to epidemi

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