A Comparative Analysis of the Relative Efficacy of Vector-Control Strategies against Dengue Fever

TL;DR

This study models dengue transmission dynamics considering mosquito life stages and seasonal variation, and compares the effectiveness of various vector-control strategies, highlighting adulticide as most effective.

Contribution

It introduces a comprehensive dengue model including immature stages and seasonal effects, and evaluates the relative efficacy of different vector-control methods.

Findings

Adulticide is the most effective control strategy.

Reducing mosquito biting rates is as effective as adult mosquito control.

Current methods focus on breeding site destruction, but host contact reduction is highly efficient.

Abstract

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.