1793 Philadelphia yellow fever epidemic immune to the fever. Many of the slaves in Charleston in 1742 could have gained immunity before having been transported from Africa, by having been exposed to yellow fever in a mild case. People who survived one attack gained immunity. A total of 240 blacks died, in proportion to their population at the same rate as whites. Given the limited resources and knowledge of the times, the city's response was credible. The medical community did not know the natural history of yellow fever, a viral infection spread by the "Aedes aegypti" mosquito. Efforts to clean the city did not defeat
History of yellow fever word of an epidemic would cause a quarantine to be placed on the city, and their trade would suffer. In such epidemics, steamboats frequently carried passengers and the disease upriver from New Orleans to other cities along the Mississippi River. The epidemic was dramatized and featured in the plot of the 1938 film "Jezebel", starring Bette Davis. Yellow fever was a threat in New Orleans and south Louisiana virtually every year, during the warmest months. Among the more prominent victims were: Spanish colonial Governor Manuel Gayoso de Lemos (1799); the first and second wives (d. 1804, 1809) of territorial Governor