This article comments that factors other than drought, such as disease, may have been at work in accounting for the disappearance of some Anasazi groups. If it is found that disease was a major factor, it would be unprecedented. As far as has been determined, the Anasazi didn’t experience exotic, culture-busting pathogens until Columbus made landfall.

William Preston
California Polytechnic State University
San Luis Obispo, Calif.