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Malaria - and its cousin, yellow fever - had significant implications during the war and the debilitating consequences of the disease were already certain before the Civil War had started in earnest and well before its final history had been written.
Yellow fever is a disease caused by the bite of the Aedes aegypti mosquito. It does not occur in the U.S. but is common in parts of Africa and South America. The symptoms of yellow fever include fever, chills, headache, backache, nausea, and vomiting; jaundice can also occur.