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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 viral disease spread to humans, as well as between certain other primates and humans, by the bite of infected mosquitoes. The virus is called simply Yellow fever virus, named for the jaundice that affects some patients, and belongs to the virus family Flaviviridae. Yellow fever is endemic in areas of Latin America and Africa, while imported cases have appeared throughout the world.