A possible connection between the 1878 yellow fever epidemic in the southern United States and the 1877-78 El Nino episode

One of the most severe outbreaks of yellow fever, a viral disease transmitt ed by the Aedes aegypti mosquito, affected the southern United States in th e summer of 1878. The economic and human toll was enormous, and the city of Memphis, Tennessee, was one of the most affected. The authors suggest that as a consequence of one of the strongest El Nino episodes on record-that w hich occurred in 1877-78-exceptional climate anomalies occurred in the Unit ed States (as well as in many other parts of the world), which may have bee n partly responsible for the widespread nature and severity of the 1878 yel low fever outbreak. This study documents some of the extreme climate anomalies that were record ed in 1877 and 1878 in parts of the eastern United States, with particular emphasis on highlighting the evolution of these anomalies, as they might ha ve contributed to the epidemic. Other years with major outbreaks of yellow fever in the eighteenth and nineteenth centuries also occurred during the c ourse of El Nino episodes, a fact that appears not to have been noted befor e in the literature.