Middle Passage
The enslaved peoples' living conditions on the slave ships were horrific.  Diseases spread very quickly because the enslaved people were so crowded together, and because there was no sanitation.  The most common diseases were dysentery, scurvy, smallpox, syphilis, and measles.  Many enslaved African people were killed by disease during the Middle Passage.  On longer trips, even more enslaved people died, because there was less food and water (this made dysentery and scurvy more common).  Also, many slaves became too depressed to eat.