. . an epidemic broke out, a sickness of pustules. It began in Tepeilhuitl. Large bumps spread on people; some were entirely covered. .[The victims] could no longer walk about, but lay in their dwellings and sleeping places, . . And when they made a motion, they called out loudly. The pustules that covered people caused great desolation; very many people died of them, and many just starved to death; starvation reigned, and no one took care of others any longer.
Excerpt and illustration from Sahagún, Historia general de las cosas de Nueva España , c. 1575-1580; ed., tr., James Lockhart, We People Here: Nahuatl Accounts of the Conquest Mexico (Univ. of California Press, 1993)
More astonishing than the difference between the length of the lists of Old World's and New World's domesticated animals is the difference between the lengths of the lists of infectious diseases native to the two. The New World had only a few, possibly because humans had been present there and had lived in dense populations, cities, for a short time compared to the Old. Possibly of greater importance is the relative lack of domesticated herd animals in America, one of our richest sources of disease micro-organisms. (For instance, we share influenza with pigs and other barnyard animals).