Yellow fever cycle, both in Africa and South America, a sylvatic cycle (forest or jungle cycle) is present, where "Aedes africanus" (in Africa) or mosquitoes of the genus "Haemagogus" and "Sabethes" (in South America) serve as vectors. In the jungle, the mosquitoes infect mainly nonhuman primates; the disease is mostly asymptomatic in African primates. In South America, the sylvatic cycle is currently the only way humans can become infected, which explains the low incidence of yellow fever cases on the continent. People who become infected in the jungle can carry the virus to urban areas, where "A. aegypti" acts as a vector.
Colorado tick fever Colorado tick fever Colorado tick fever (CTF) (also called mountain tick fever, American tick fever, and American mountain tick fever) is a viral infection (Coltivirus) transmitted from the bite of an infected Rocky Mountain wood tick ("Dermacentor andersoni"). It should not be confused with the bacterial tick-borne infection, Rocky Mountain spotted fever. The type species of the genus "Coltivirus", Colorado tick fever virus (CTFV) infects haemopoietic cells, particularly erythrocytes, which explains how the virus is transmitted by ticks and also accounts for the incidence of transmission by blood transfusion. The disease develops from March to September, with the highest infections