Did they try to show that more disease happens in the presence of the supplied virus than without the virus? If the virus was replicating, then they'd find more of the virus' material in the test group than the control, but that doesn't prove more disease. Then we'd have the challenge of showing that this little reaction was self-sustaining by introducing healthy tissue. If it did, then maybe they'd find out what actually was causing the disease. Again, they'd have to see if the disease progresses further with the presence of the virus than without.
How much of this investigation did they do with this study?