Yellow fever is a hemorrhagic fever that has a viral etiology. The virus is transmitted to humans by infected mosquitoes (Aedes aegyptii). It is called yellow fever due to the jaundice that affects some patients causing yellow eyes and yellow skin. The disease itself may be limited to mild symptoms or may cause severe illness or even death. Yellow fever occurs exclusively in Africa and South America. Annually, it is estimated to cause 200,000 cases, and the death toll is estimated to be around 30,000. It is a notifiable disease under the International Health Regulations of the World Health Organization (WHO), and member states are officially obliged to notify yellow fever cases to the WHO.