It means they have been exposed to anthrax. It does not mean they are infected.
We really need to get a handle on our terms here. What does "tested positive for exposure" mean? Do they have anthrax, or just the antibodies?It means they have been exposed to anthrax. It does not mean they are infected.
Ain't that a tautology?
BTW, exposure doesn't necessarily mean infection, but doesn't rule it out, either.
I know what "exposure" probably meant in this context, but my point is that the way this story is breaking, the news media needs to be very precise was they get the information out there.