Fig 4. The transmission of dengue virus between mosquitoes and humans.
Black dash-dotted lines show direction of transmission between humans and mosquitoes. For mosquito, A denotes immature stage, and M describes mature mosquito stage (including susceptible Sm, incubating Em, and infectious Im), and M = Sm + Em + Im. For human, all hosts are divided into six stages for dengue transmission: susceptible Sh, incubating Eh, asymptomatic infectious Yh, infectious Ih, imported infectious Wh and recovered Rh, where Nh = Sh + Eh + Yh + Ih + Wh + Rh is the total human population.