Why was disease the leading cause of death of enslaved Africans on the middle passage

Chained enslaved Africans were often unable to reach toilet buckets. This meant the rapid spread of diseases such as diarrhoea and the 'bloody flux' (dysentry) that killed many of the weakened captured Africans. They were also vulnerable to other diseases such as malaria, pleurisy, yellow fever, smallpox and scurvy.

The disorientation of Africans mystified their captors who described a 'fixed melancholy'. Some captives refused to move about, refused food and eventually died. Others took more immediate steps to remove their and their relatives bodies from capture. They threw themselves and their children overboard in acts of suicide and infanticide that many of them believed would quicken their return to Africa. This happened so often that slaving ships were fitted with nets to try and prevent it.

Death rates on the ships varied, although generally in the early trade 20% and above of enslaved Africans died on board the ships. This rate fell to 10% in the late eighteenth century, only to rise again during the illegal transatlantic slave trade after 1807.