Alexander Moffett

Alexander Moffett died of Yellow Fever at the age of 16.

Yellow fever is an acute systemic illness - a hemorrhagic fever - caused by the Flavivirus. Acute means it comes on (onset) rapidly, while systemic means it affects the whole body. In severe cases yellow fever causes a high fever, bleeding into the skin and the death of cells in the liver and kidneys. Liver damage results in severe jaundice - yellowing of the skin; hence the name "yellow fever".

The mosquito Aedes aegypti, and some other species transmit the virus to humans. Aedes aegypti is found in tropical and subtropical parts of South America, parts of the Caribbean, and Africa (not Asia). Apart from mosquitoes, the only other known hosts of the virus are primates and humans.

Experts believe yellow fever originated in Africa and was introduced to South America via the slave trade in the 16th century. Several major yellow fever epidemics have taken place in Europe, the Americas and Africa since the 17th century. It was deemed one of the most dangerous infectious diseases in the 19th century.

According to the World Health Organization (WHO), there are approximately 200,000 cases of yellow fever worldwide each year, and 30,000 deaths. About 90% of all cases occur in Africa.

In the middle of the 20th century a safe and effective vaccine was created. However, since the 1980s the number of yellow fever cases has increased, making it a reemerging disease.

There are two classifications of yellow fever:

Jungle yellow fever - it is spread by jungle mosquitoes and mainly affects monkeys. Humans who go into the jungle can become infected by mosquitoes that became infected by biting infected monkeys, and can be the source of urban outbreaks of the disease.

Urban yellow fever - this is spread when an Aedes aegypti mosquito bites an infected human or monkey and then goes on to bite other people. Urban yellow fever is most likely to occur in settlements close to the jungle, where infected monkeys and mosquitoes live. Urban yellow fever is extremely rare in the Americas. Put simply, a human may go into the jungle, be bitten by an infected mosquito, come back to their settlement, and infect mosquitoes who bite them there; those mosquitoes will then infect other people.

According to Medilexicon's medical dictionary:

Yellow fever is "a tropical mosquito-borne viral hepatitis, due to yellow fever virus, a member of the family Flaviviridae, with an urban form transmitted by Aedes aegypti, and a rural, jungle, or sylvatic form from tree-dwelling mammals by various mosquitoes of the Haemagogus species complex; characterized clinically by fever, slow pulse, albuminuria, jaundice, congestion of the face, and hemorrhages, especially hematemesis; used to occur in epidemics mainly in port cities, especially in late summer, with 20-40% case fatality rates; immunity to reinfection accompanies recovery."