Yellow fever seems to play a role in single, sudden breakouts of the disease. Three epidemiologically different infectious cycles occur, in which the virus is transmitted from mosquitoes to humans or other primates. In the "urban cycle", only the yellow fever mosquito "A. aegypti" is involved. It is well adapted to urban areas, and can also transmit other diseases, including Zika fever, dengue fever, and chikungunya. The urban cycle is responsible for the major outbreaks of yellow fever that occur in Africa. Except for an outbreak in Bolivia in 1999, this urban cycle no longer exists in South America. Besides the urban
Yellow fever symptoms of fever, pain, nausea, and vomiting 6-10 days after leaving the affected area) is treated seriously. If yellow fever is suspected, the virus cannot be confirmed until 6-10 days after the illness. A direct confirmation can be obtained by reverse transcription polymerase chain reaction, where the genome of the virus is amplified. Another direct approach is the isolation of the virus and its growth in cell culture using blood plasma; this can take 1-4 weeks. Serologically, an enzyme-linked immunosorbent assay during the acute phase of the disease using specific IgM against yellow fever or an increase in specific IgG