Q9 - Birds and mammals can be

[Elizabeth.Naff]

Sure, only mosquitos can infect a human being. And the human being cannot infect the mosquito. But I do not see how these ideas together make for answer choice (E).

Given that mosquitos are the only way though which mammals and birds may become infected, I chose answer choice (B).

Thanks!

[ymcho2013]

Only mosquitos infect birds and mammals/humans.
Humans cannot infect mosquitos.

So E) saying that an infected person wasn't the cause of the virus spreading to north america.

Its quite unlikely that the infected humans caused the spread of the virus because even if humans were infected in north america, they cannot possibly infect the mosquitos in north america (because of the last sentence in the stim.).

And if infected humans cant infect mosquitos in NA, then other humans cant be infected by the virus (because humans can only be infected by mosquitos and the mosquitos cant be infected).

Therefore, the virus' spread from Africa to NA can't really be the result of the spread of human carriers - human carriers have no impact on further spreading the virus.

Perhaps there was some other method by which the virus spread - maybe someone captured a lot of infected mosquitos in Africa and sent them over to the US, etc.

Hope this helps!

[Gerald]

Here's my explanation. Hope it helps!

PT65, S4, Q9 (Inference)
The statements above, if true, most strongly support which one of the following?

(A) West Nile virus will never be a common disease among humans.
(B) West Nile virus is most common in those parts of North America with the highest density of mosquitoes.
(C) Some people who become infected with West Nile virus never show symptoms of illness.
(D) West Nile virus infects more people in northern Africa than it does in North America.
(E) West Nile virus was not carried to North America via an infected person.

(E) is correct.

This is an inference question, so we are out of the assumption family and no longer concerned with whether the stimulus contains an argument. Instead, we simply gather the facts from the stimulus. Then we ask: what else do I know?

We are told 1) birds and mammals can get West Nile only through mosquito bites; 2) mosquitoes become infected by biting infected birds or mammals; 3) WN came to America in the 1990s; and 4) though humans can get the virus, mosquitoes can’t get WN by biting humans.

No obvious inferences or connections jump out, which is fine. It is often difficult to predict the tested inference, but it can still be beneficial to briefly stew over the facts to see if they whisper anything in your ear. After letting them marinate, let’s take the facts to the answer choices and see which answers are supported.

(A) Never be common? Does the stimulus discuss how common the disease is in humans? No. And "never" is a strong word that the stimulus would really have to back up. Such strong words in inference questions should raise your hackles. "Never" is not supported. Eliminate.

(B) Again with the "common." Does the stimulus discuss whether and where the disease is common in North America? No. Eliminate.

(C) Symptoms? Do you know what the symptoms of WN are after reading the stimulus? Me neither. Eliminate.

(D) Tempting maybe, because WN was first detected in northern Africa and only made it to North America during the 1990s. We might think WN does better in its homeland than in North America, but maybe WN loved grunge music and flannel shirts and really flourished once it got here and now WN infects more people in North America than northern Africa. It’s possible. The stimulus never mentions how many people, on any continent, contract WN. Eliminate.

That leaves (E) West Nile virus was not carried to North America via an infected person.

Is this information supported? Yes. We know the disease can only spread to birds and mammals after a bite from an infected mosquito, and we also know mosquitoes can’t catch WN from people. So, if the only instance of WN in North America was in a person, could it spread to anything else? Nope. Something other than a human must have brought the infection over here. Perhaps zombies? At any rate, this is our answer.

[peru_lpz]

For anyone still stuck on this question, let me just say that at least for this question and many most strongly supported, and even some must be true (AKA inference questions, as well as, other question), POE could be your BEST friend.

PROCESS OF ELIMINATION, sometimes hooks me up, and this question was not the exception.
Answer A: "Will never" out
B: "most common in regions with highest density of mosquitos". Really, maybe mosquitos like isolation and they avoid high dense mosquitos population. Who knows.
C) Some people will 1)NEVER and 2) SHOW SYMPTONS... I was stuck on these one, but then I remembered my good old friend POE, and he whispered "SYMPOTNS", where in the stimulus are they mentioning such thing.
D) Infects more people in Africa the North America? But the stimulus says that's people SOMETIMES get infected. Not supported More /less who knows?
E) And is it supported because, honestly, my thoughts were "sure". I know 100% that A-B-C-D where 100 % wrong and only one of five can be right; time is running out, ill justify it later.

Please do not interpret this to say that one should ONLY rely on POE, or that it will be suffice for every question, or even get one a 180, but do note that it is a strong tool available, especially if you are not so sure why an answer choice is 100 % right, but 100 % the other answers are wrong.

[ttunden]

I was stuck between B and E during the test but picked E which is correct

B - this is wrong because it is telling us that west nile virus is most common in NA(the parts with highest density of mosquitos)
first off, there is no evidence telling us that west nile is most common in NA. One would think that it would be most common in Africa since it only relatively recently spread to America. So, no support for saying it is most common in America in the stimulus. Eliminate.

E- this is correct because you can safely infer this from the stimulus, there is ample evidence to support this view point. Humans cannot infect any mosquito. Mosquito's however can infect birds and mammals. So yeah we can infer that it was not spread to America by an infect person since if it was..... it would be the infected person who spread the disease in North America. From the stimulus though, it doesn't tell us that humans can infect anybody. So this is safe to infer.

C- no support. nothing in the stimulus says this or leads to this
A- nope, somewhat contradicted and way 2 strong

[hannahhodge]

The thing that I find confusing about the proper answer choice (West Nile virus was not carried to NA via and infected person) is that it seems to equivocate between "carrying" and "spreading." The virus could very well have been carried to NA as an isolated case or cases.

[tommywallach]

Hey Hannah,

It's always worth remembering that it isn't so much "Is this answer perfect?" as "Are any of the other answers defensible?" If another answer appeals to you more, then there's a problem. If the answer in question feels like the only possible correct one, even if it's flawed, then it's not worth worrying about.

-t

[uhdang]

Have been obsessed with this question, and I figured out what was troubling about this question.

The wording of "West Nile virus was not carried to" contains essentially two different meanings, and it felt very annoying to NOT clearly understanding those different meanings are (although the fact that there are two different implication itself came to me later as I kept on trying to understand this question).

First of all, "carried to" could mean literally and physically moving an object from A to B. So, if we think of "carry" in this sense, it feels like this is supported by the stimulus. Because, since the stimulus said, "the virus was originally detected in northern Africa and spread to North America", it could easily have been the case where an American traveling northern Africa got bit by a mosquito with the virus, and came back to US. In a sense that this virus has been physically carried from Africa to America, this sounds very well COULD BE supported. In fact, it's hard to imagine there had never been this case unless vaccination process is flawless. The bottom line is that we are not 100% certain although it is possible.

However, physically transportation is NOT what it is entailing essentially.

Another sense that this "WNV was not carried to N.America" implies is that, since we already know this virus HAS spread to N.America, the first time this virus was transported and CAUSED the spread was NOT via an infected person. Although subtle, the virus that's "carried to" here indicates the VERY virus that started the whole process of infection in N.America. (Before I was able to word this out, it felt like there was a little tumor in my brain that I really want to scratch but unable to reach my finger) In this sense, this is 100% supported by the stimulus, because it's given that "the virus never becomes abundant enough in human blood to infect a mosquito", which is necessary for the virus to spread out.

In other words, although there could have been an infected person from Africa coming to N.America, that virus never got to be spread out due to a given reason. Consequently, in a sense whether the first virus that caused the spread in N.America has been via an infected person or not, it MUST NOT be true.

I welcome ALL kinds of feedback, especially critical ones.

[ohthatpatrick]

Yeah, in the context of diseases, a "carrier" is often meant to mean "someone who is infected with a disease and capable of spreading it, though not necessarily exhibiting any symptoms."

So in part LSAT wants us to use the context of "vectors for transmitting diseases" to decide what they mean by "carried" from one continent to another.

And then in part, the ambiguity is tolerable because it's just a "most strongly support" question.

Glad you finally scratched your itchy tumor.