What is yellow fever?

When the Europeans began importing African slaves they brought yellow fever, which is also known as "yellow jack" to the Americas. The illness ripped through the colonies, decimating people living on farms and even in major cities.

When Napoleon sent an army of 33,000 to France's landholdings in North America, the disease killed 29,000 of those soldiers-shocking Napoleon so much that he decided the territory was not worth the risk of additional losses. France sold the territory to the United States in 1803; a transaction recorded in history as the Louisiana Purchase.

Yellow fever spreads from person to person through feeding mosquitoes. Its typical symptoms include fever, chills, headache, muscle ache, backache and vomiting. Symptoms can range from mild to deadly. Severe infections can lead to shock, bleeding, liver and kidney failure. When the liver fails it causes jaundice or yellowing of the skin, which gives the illness its name.

Despite better mosquito management, the use of vaccinations and improved treatment procedures, epidemics of the illness continue even to this day in Africa and South America.

Yellow fever is a serious viral infection transmitted by mosquitoes. It occurs mostly in Africa and South America.

Symptoms of yellow fever usually appear suddenly and may include:

• Fever.
• Headache.
• Slow heartbeat.
• Yellowish skin (jaundice).
• Vomiting.
• Bleeding from the mucous membranes of the nose and mouth. Gastrointestinal bleeding may cause the person to vomit blood.

There is no specific treatment for yellow fever. Many cases of yellow fever are mild, and people recover completely within a few days to a week. More severe cases may lead to serious bleeding, failure of the heart, liver, or kidneys, and death within a week to 10 days.