Archaeologists have gleaned important clues on the rise and fall of the mighty Inca empire and the civilizations that existed before it from fossilized mites that survived on the dung of llama, the South American domesticated beast of burden.
The fossils preserved in sediments at a lake about 50 kilometers from Cuzco, which formed the center of activity of the Inca empire, shows how the empire grew in size and influence in the early 15th century. When the Spanish conquistadors came to Peru in the 1530s, the empire was stretching from the current day Colombian border to the middle of Chile. However, in a matter of 100 years, the 30 million population in the region was reduced by 90 per cent, afflicted by newer diseases like influenza and smallpox, brought by the Europeans.
I'm guessing the mites washed in (blew in?) on sediment carried into the lake. But this part:
The research shows that after a period of sharp growth, the civilization's power waned even before the arrival of the Spanish because of the arrival of the European diseases to which the people or the animals had no resistance.
shows how disease can travel well in advance of the actual people who introduced it.