Yellow fever Because of this sylvatic cycle, yellow fever cannot be eradicated except by eradicating the mosquitoes that serve as vectors. In Africa, a third infectious cycle known as "savannah cycle" or intermediate cycle, occurs between the jungle and urban cycles. Different mosquitoes of the genus "Aedes" are involved. In recent years, this has been the most common form of transmission of yellow fever in Africa. Concern exists about yellow fever spreading to southeast Asia, where its vector "A. aegypti" already occurs. After transmission from a mosquito, the viruses replicate in the lymph nodes and infect dendritic cells in particular. From there,
Yellow fever they reach the liver and infect hepatocytes (probably indirectly via Kupffer cells), which leads to eosinophilic degradation of these cells and to the release of cytokines. Apoptotic masses known as Councilman bodies appear in the cytoplasm of hepatocytes. Fatality may occur when cytokine storm, shock, and multiple organ failure follow. Yellow fever is most frequently a clinical diagnosis, made from symptoms and where the infected person was before becoming ill. Mild courses of the disease can only be confirmed virologically. Since mild courses of yellow fever can also contribute significantly to regional outbreaks, every suspected case of yellow fever (involving