Yellow fever

Yellow fever (also called yellow jack, or sometimes black vomit or American Plague) is an acute viral disease. The yellow refers to the jaundice symptoms that affect some patients. The virus is usually carried by mosquitoes. Symptoms in severe cases include fever, chills, bleeding into the skin, rapid heartbeat, headache, back pains, and extreme prostration. Nausea, vomiting, and constipation are common. Jaundice usually appears on the second or third day. After the third day the symptoms recede, only to return with increased severity in the final stage, during which there is a marked tendency to hemorrhage internally. The patient then lapses into delirium and coma, often followed by death. During epidemics the fatality rate was often as high as 85%.

Yellow Fever in Atlantis
The terror of yellow fever was such that during the Atlantean War of Independence, General Victor Radcliff was able to forestall a British attack on New Hastings by running up flag that signalled the town was suffering a yellow fever epidemic.