One of these days, they are goign to open a tomb or grave and soem nasty unknown pathogen is going to be released, something perhaps akin to the sweating sickness.
I have the same concern.
Here I New Mexico, there are several well preserved towns dating from the pre-Columbian period or thereabouts (1400 to 1550 AD).
All the Indians just died for unknown reasons. Unburied bodies found in hidey holes.
Best guess from locals is some sort of hantavirus.
Apparently this killed 95% of the North American population before Europeans even showed up.
We get occasional outbreaks out this way. The CDC comes and burns down the house.
-PJ