<P> Similarly, yellow fever is thought to have been brought to the Americas from Africa via the Atlantic slave trade . Because it was endemic in Africa, many people there had acquired immunity . Europeans suffered higher rates of death than did African - descended persons when exposed to yellow fever in Africa and the Americas, where numerous epidemics swept the colonies beginning in the 17th century and continuing into the late 19th century . The disease caused widespread fatalities in the Caribbean during the heyday of slave - based sugar plantation . The replacement of native forests by sugar plantations and factories facilitated its spread in the tropical area by reducing the number of potential natural predators . Yet, the means of the transmission was unknown until 1881, when Carlos Finlay suggested that the disease was transmitted through mosquitoes, now known to be female mosquitoes of the species Aedes aegypti . </P> <P> The history of syphilis has been well - studied, but the exact origin of the disease is unknown and remains a subject of debate . There are two primary hypotheses: one proposes that syphilis was carried to Europe from the Americas by the crew of Christopher Columbus in the early 1490s, while the other proposes that syphilis previously existed in Europe but went unrecognized . These are referred to as the "Columbian" and "pre-Columbian" hypotheses . The first written descriptions of the disease in the Old World came in 1493 . The first large outbreak of syphilis in Europe occurred in 1494 / 1495 in Naples, Italy, among the army of Charles VIII, during their invasion of Naples . </P> <P> Prior to the trans - Atlantic slave trade, Columbus directly participated in and championed the slave trade . Upon landing in what is now known and assumed to be San Salvador Island, Columbus encountered the Taíno . In his journal of 1492, Columbus noted that </P> <P> It appears to me, that the people are ingenious and would be good servants and I am of opinion that they would very readily become Christians, as they appear to have no religion . They very quickly learn such words as are spoken to them . If it please our Lord, I intend at my return to carry home six of them to your Highnesses, that they may learn our language . </P>

Columbian exchange from old world to new world