Yellow fever is a viral disease primarily transmitted by mosquitoes, particularly the Aedes aegypti species in tropical and subtropical regions of Africa and South America. The virus belongs to the Flaviviridae family and can cause severe illness, characterized by fever, headache, muscle pain, nausea, and jaundice (yellowing of the skin and eyes), from which the disease derives its name.

In mild cases, symptoms can resolve within a few days to a week. However, in severe cases, the disease progresses to a toxic phase, leading to liver damage, bleeding, and ultimately, organ failure. This severe form of yellow fever has a high mortality rate.

Yellow fever has historically been a major public health concern, with devastating outbreaks affecting populations in endemic regions. Vaccination is highly effective in preventing the disease and is recommended for travelers to areas where yellow fever is endemic.

Efforts to control the disease include mosquito control measures, such as eliminating breeding sites and using insecticides, as well as vaccination campaigns in at-risk populations. Despite these efforts, yellow fever remains a significant health threat in regions where the virus is endemic, necessitating ongoing surveillance and public health interventions.