Camillus de Lellis (1550-1614) is the Roman Catholic patron saint of nurses, hospitals, and the sick. The anniversary of his death is July 14, and this is also the day of his official memorial (everywhere except in America, where it is July 18 due to a Native American saint that takes precedence on July 14).
Camillus was a mercenary soldier who converted and began attending the sick in hospitals. His work during the epidemic of 1590 in Rome is most famous. His bio is of course at New Advent. Here are other links: