Cases began in early May of 1853, but they were at the time isolate and so far not unusual in number. Since the epidemic of 1847, some summer cases were expected. Things began taking a turn for the worse in late June. By June 26, there were nine deaths, by July 2 twenty-five. At this point, the press was not reporting the cases out of a desire to keep the populace calm. Publications began printing deaths on July 16, when papers reported 204 deaths that week alone.
Yellow fever is a viral infectious disease transmitted by mosquitoes. Early symptoms include fever, vomiting, backache, and headache. As the disease progresses, symptoms expand, slowing and weakening the pulse and causing bleeding gums and bloody urine. Jaundice can also be a more progressed symptom, hence the name yellow fever.