Abstract Yellow fever is an acute mosquito-bome flavivirus infection characterized in its full-blown form by fever, jaundice, albuminuria, and haemorrhage. Two forms are distinguished: urban yellow fever in which the virus is spread from person to person by peridomestic Aedes aegypti mosquitos and jungle (sylvan) yellow fever transmitted by tree-hole breeding mosquitoes between non- human primates and sometimes humans. Yellow fever is endemic and epidemic in tropical areas of the Americas and Africa but has never appeared in Asia or the Pacific region. Control is through vector control, prevention of mosquito bites, and yellow fever vaccination.