England

There were outbreaks of the sweating sickness several times in England, the first in 1485, which took the lives of around 15,000 people in London. It returned to England again in 1508 and another time in 1517. Then the sweating sickness jumped to continental Europe; it struck Flanders, Germany, Sweden, and several other locations during the 1520s before it reemerged in England for the last time in 1551.

The first stage of the sweating sickness included headaches, pain in the back and shoulders, dizziness, and nausea. This was followed by excessive sweating, delirium, and abdominal pain. The more severe symptoms lasted anywhere from 15 to 21 hours and accompanied extreme fatigue, which would usually end in a coma and death.

Unusually, the sweating sickness affected the upper class more than the lower and could end a life in a matter of hours. During the outbreak of 1529, King Henry VIII, who by nature had a phobia of illness, was so terrified of the sickness that he packed up and left his palace "in great haste, and went a dozen miles off" to hide from the affliction. How the disease was transmitted remains a mystery. Even more strange is that the majority of the victims were young to middle-aged men.

Recently, historians and researchers believe that the sweating sickness was caused by one of the following: typhus, influenza, botulism, or the most highly suspected hantavirus, but no definitive source of the disease has ever been found. It is believed that Prince Arthur could have died of the sweating sickness, and both of the sons of Charles Brandon, Duke of Suffolk, succumbed to the disease within hours of each other.

Sources:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3917436/

Jared Bernard for historytoday.com

Melissa Sartore for Ranker.com