There are some clues. In the human excrement found intact in another burial
site, scientists found egg remains of the trematode species Fasciola buski.
Today, this parasitic flatworm is endemic to certain areas of Thailand and is
most common where aquatic plants are cultivated, particularly the water
caltrop. The University of Otago's Dave Morseth, a parasitologist, reports that
infestation of this parasite would greatly reduce human vitality. Anemia
associated with malaria may also have affected the people greatly.