  The model considers the human population, the adult mosquito population and
the population of immature stages, which includes eggs, larvae and pupae. The
model also considers the vertical transmission of dengue in the mosquitoes and
the seasonal variation in the mosquito population. From this basic model
describing the dynamics of dengue infection, we deduce thresholds for avoiding
the introduction of the disease and for the elimination of the disease. In
particular, we deduce a Basic Reproduction Number for dengue that includes
parameters related to the immature stages of the mosquito. By neglecting
seasonal variation, we calculate the equilibrium values of the models
variables. We also present a sensitivity analysis of the impact of four
vector-control strategies on the Basic Reproduction Number and on the Force of
Infection of dengue. Each of the strategies was studied separately from the
others. The analysis presented allows us to conclude that of the available
vector control strategies, adulticide application is the most effective,
followed by the reduction of the exposure to mosquito bites, locating and
destroying breeding places and, finally, larvicides. Current vector-control
methods are concentrated in mechanical destruction of mosquitoes breeding
places. Our results suggest that reducing the contact between vector and hosts
(biting rates) are as efficient as the logistically difficult but very
efficient adult mosquitos control.
