It is not known whether bovine spongiform encephalopathy (BSE), a dise

A. seems to be the correct answer choice.
removing from the herd won't cure as the infection might already have spread to others before it became overtly visible

It is not known if disease is directly transmitted from one infected animal to another at all stages of infection.
No diagnostic tests are available to identify infected animals before the animals show overt symptoms.
So, disease cannot be eradicated by removing the animals which shows the symptoms.


(A) removing from the herd and destroying any diseased animal as soon as it shows the typical symptoms of advanced BSE
Yes this seems correct according to our logic.

(B) developing a drug that kills the agent that cause BSE, and then treating with that drug all cattle that might have the disease
If drug is developed to kill the agent that cause BSE, disease can be eradicated.

(C) destroying all cattle in areas where BSE occurs and raising cattle only in areas to which BSE is known not to have spread
Again destroying all cattle in the area where BSE occurs will eradicate the disease.

(D) developing a vaccine that confers lifelong immunity against BSE and giving it to all cattle, destroying in due course all those animals for which the vaccine protection came too late
similar to B & C

(E) developing a diagnostic test that does identify any infected animal and destroying all animals found to be infected
If diagnostic test is developed, it will help to identify the infected animal and hence the eradication of disease is possible.

It is not known whether bovine spongiform encephalopathy (BSE), a disease of cattle invariably deadly to them, can be transmitted directly from one infected animal to another at all stages of the infection. If it can be, there is now a reservoir of infected cattle incubating the disease. There are no diagnostic tests to identify infected animals before the animals show overt symptoms. Therefore, if such direct transmission occurs, the disease cannot be eradicated by______

The argument states that: a) If the disease can be transmitted from one animal to another, there will be a reservoir of infected cattle.
b) there are no diagnostic tests to identify infected animals until they show symptoms.

Which one of the following best completes the argument that the disease can't be eradicated. hence, we need to find 1 way considering the information given the stimulus that can't eradicate the disease.

(A) removing from the herd and destroying any diseased animal as soon as it shows the typical symptoms of advanced BSE : they can be identified once they show symptoms, however, since it is unknown if the disease can be transmitted at all levels of infection, it could be possible that they have already infected the herd already, so this would not lead to eradication of the disease. Correct.

Let's take this question top to bottom. This is technically an inference question, though that can be hard to see. However, we are inferring where the argument would go based on what's come before, which is no different from any question asking "Which of the following can be inferred from the information above?"

Knowing that, we just need to think about the premises that are given:

1) It's unknown if BSE can be transmitted at all stages of infection.

2) If it can, there is a reservoir of infected cattle incubating BSE.

3) There are no diagnostic tests to identify infected animals before the animals show overt symptoms.

4) Direct transmission has occurred.

(A) Correct. Let's think about what would happen if we did this. Any cow/bull with symptoms will be killed. However, it will already have infected other cows, which don't yet show symptoms. So we'll never be able to get rid of the disease this way.

(B) is totally plausible. If we can develop a drug that kills BSE, then we can use it to treat all the cows at once, so BSE can't be spread.

(C) may be totally dramatic, but it would work. If we kill every single infected cow, then start over in an area without any BSE, we will get rid of BSE.

(D) is also a great idea. If we inoculate all cows against any future BSE, then let all the infected ones die, we'll be left only with healthy cows that can't develop BSE.

(E) is a big hypothetical, but if it could be accomplished, it would work. Right now, we know there isn't a diagnostic test that works to reveal cows before they show symptoms. But if we could see every single cow that had the illness, we could kill them all, and all the cows that were left would be clean.

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