 Conversely, many enslaved Africans were taken from regions of Africa which hosted particularly potent strains of the disease, so the Africans had already developed natural resistance to malaria.This, Esposito argued, resulted in higher malaria survival rates in the American south among enslaved Africans than among European labourers, making them a more profitable source of labour and encouraging their use.Africans played a direct role in the slave trade, selling their captives or prisoners of war to European buyers.