Yellow fever and several species of mosquitoes. In cities, it is spread primarily by "Aedes aegypti", a type of mosquito found throughout the tropics and subtropics. The virus is an RNA virus of the genus "Flavivirus". The disease may be difficult to tell apart from other illnesses, especially in the early stages. To confirm a suspected case, blood sample testing with polymerase chain reaction is required. A safe and effective vaccine against yellow fever exists, and some countries require vaccinations for travelers. Other efforts to prevent infection include reducing the population of the transmitting mosquito. In areas where yellow fever is common
Yellow fever cycle has yet been established, scientists believe this could happen again at any point. An outbreak in Paraguay in 2008 was thought to be urban in nature, but this ultimately proved not to be the case. In Africa, virus eradication programs have mostly relied upon vaccination. These programs have largely been unsuccessful because they were unable to break the sylvatic cycle involving wild primates. With few countries establishing regular vaccination programs, measures to fight yellow fever have been neglected, making the future spread of the virus more likely. In the hamster model of yellow fever, early administration of the antiviral