YELLOW FEVER VIRUS

GROUP - IV 

ORDER - None assigned

FAMILY - Flaviviridae

GENUS - Flavivirus

GENOME - Linear, single-component, single stranded RNA of about 11,000 nucleotides, encoding ten proteins from a single polyprotein

GEOGRAPHY - Africa, Central America, South America

HOSTS - Humans

ASSOCIATED DISEASES - Yellow fever, yellow jack, yellow plague

TRANSMISSION - Mosquitoes

VACCINE - Live attenuated virus

Source Wikipedia

A virus spread by human migrations Before the sixteenth century, yellow fever was endemic in parts of Africa, and individuals were exposed from an early age, so many had immunity. The slave trade spread yellow fever from eastern Africa to west Africa, and then brought yellow fever to South America, and later North America, in the seventeenth century. The disease may have fueled the slave trade, because the newly developing regions of the Americas needed workers that were resistant, and these could only be found in eastern Africa.

Source wikipedia

North America saw numerous epidemics until the early twentieth century. Sir Walter Reed proved that the virus was transmitted by mosquitoes, the first demonstration of a mosquito-borne virus. The epidemics disappeared in North America after 1905, but still plague other parts of the world, including Africa and Latin America, causing about 30,000 deaths every year.

The virus infection usually causes a fairly mild, short-lived flu-like disease, but in about 15 percent of individuals a second phase occurs that has a high fatality rate. In the second phase the fever returns, and abdominal pains occur as well as severe liver damage, which results in the jaundice, or yellow skin that is characteristic and responsible for the name of the virus. In severe epidemics the fatality rates can be as high as 50 percent.

The virus is transmitted by mosquitoes in the Aedes genus, the yellow fever mosquito and the Asian tiger mosquito. The virus has an urban cycle and a forest cycle. In the urban cycle it is transmitted between mosquitoes and humans, while in the forest it also cycles between mosquitoes and other non-human primates, making eradication impossible. The vaccine for Yellow fever virus was developed as an attenuated virus in 1937, and was used extensively in World War II. In 2006 a massive vaccination campaign was initiated in West Africa, although the Ebola epidemic likely caused some disruption of this effort.