A recent study suggests that Alzheimer’s disease, which attacks the human brain, may be caused by a virus.
Conclusion (to conclude)
Alzheimer's disease might be caused by a virus.
Evidence
A study injected blood from 11 volunteers with Alzheimer's disease into rats, which later showed symptoms of Creutzfeldt-Jakob disease, a disease caused by a virus.
Evaluate
This argument fits the Explain Curious Fact pattern. The study presents a Curious Fact: injecting blood from Alzheimer's patients into rats caused symptoms of another viral disease, Creutzfeldt-Jakob disease.
The Author's Explanation is that Alzheimer's might also be caused by a virus. The evidence connects the appearance of Creutzfeldt-Jakob disease (a known viral disease) with blood from people with Alzheimer's being injected into the rats, suggesting a viral link.
To strengthen this hypothesis, we need to increase the plausibility that Alzheimer's is indeed caused by a virus. We could do this by showing stronger connections between Alzheimer's and viral infections or by eliminating alternative explanations (i.e., showing this phenomenon was not due to something else in the blood causing the rats to develop Creutzfeldt-Jakob disease).
Goal
Let's find an answer that supports the idea that Alzheimer's disease is likely to have a viral cause similar to Creutzfeldt-Jakob disease.