how is the yellow fever transmitted
Yellow fever (YF) is a viral haemorrhagic fever transmitted by infected mosquitoes. Yellow fever can be recognized from historic texts stretching back 400 years. Infection causes a wide spectrum of disease, from mild symptoms to severe illness and death. The yellow in the name is explained by the jaundice that affects some patients, causing yellow eyes and yellow skin. There are three types of transmission cycle: sylvatic, intermediate and urban. All three cycles exist in Africa, but in South America, only sylvatic and urban yellow fever occur.