Cholera, which is believed to be spread from Irish immigrant ships, spreads throughout the Mississippi River system, killing over 4,500 in St. Louis and over 3,000 in New Orleans. Thousands die in New York–a major destination for Irish immigrants. Schools are transformed into hospitals and businesses shut down. This contributes to a wave of anti-Irish sentiment and violence. President James K. Polk will die of cholera in 1849.