Yellow fever is an acute viral disease. From 1793 to 1822 yellow fever was one of the most dreaded diseases in the port cities of the United States. A ship carrying persons infected with the virus arrived in Hampton Roads in southeastern Virginia in June of 1855. The disease spread quickly through the community, eventually killing over 3,000 people, mostly residents of Norfolk and Portsmouth. In the 1878 a devastating epidemic ravaged the Mississippi Valley as far north as Memphis, Tennessee.