[davesque]

I'm not sure about this case, but wouldn't it be okay to say something like that if none of the diagnostic criteria for a disease are met?

[phkahler]

This is a new mystery disease, there is little known about it. I'd say they need to positively identify a case as something else to say it's not the new thing.

[sudosysgen]

They can't say that, because their point is that these are all existing diseases, so for that point to be true they'd have to meet the criteria.