[blam]

"The high mortality rate leads me to think that this was a new plague introduced into a virgin population."

Very high rates indeed. The article I have in front of me (Discover Magazine) goes to greater lengths to dismiss it as having been introduced by the Europeans.

"These symptoms are not consistent with known European or African diseases present in Mexico during the 16th century."

[Tinman73]

High disease mortality rates are not uncommon among slave populations through history.

The amount of care given to a slave populations are rare.

They were denied the basics of life enhancing factors (food, water, shelter, immune strengthening rest) and were generally held in concentrated living quarters, Be that a single compound or the slum section of cities. Also pest controls in these areas were not a concern to the masters.

[Little Bill]

The symptoms included high fever, severe headache, vertigo, black tongue, dark urine, dysentery, severe abdominal and thoracic pain, large nodules behind the ears that often invaded the neck and face, acute neurological disorders, and profuse bleeding from the nose, eyes, and mouth with death frequently occurring in 3 to 4 days.

Sounds like Black Plague to me. Similar symptom's