Models of Disease Vector Control: When Can Aggressive Initial Intervention Lower Long-Term Cost?

Area of Science:

• Mathematical modeling of infectious diseases
• Vector control strategies
• Epidemiology

Background:

• Insecticide spraying is crucial for controlling vector-borne diseases like Chagas disease.
• Vector re-infestation occurs from neighboring units and sylvatic areas.
• Insecticide efficacy diminishes over time, necessitating dynamic control models.

Purpose of the Study:

• To investigate three ODE-based models for insecticide spraying dynamics.
• To analyze the dual-rate effect of initial aggressive spraying versus sustained moderate spraying.
• To determine conditions for the effectiveness and robustness of this dual-rate effect.

Main Methods:

• Utilized ordinary differential equation (ODE)-based models to simulate infestation dynamics.
• Modeled housing units as hosts and insecticide spraying as host removal.
• Incorporated reservoir dynamics and potential heterogeneity in housing units.

Main Results:

• An initial intensive spraying phase can lead to low, sustainable infestation levels at lower long-term costs.
• Sustained moderate spraying, at the same average cost, results in less significant long-term infestation reduction.
• The dual-rate effect is robust even with heterogeneity in housing unit properties.

Conclusions:

• Aggressive initial insecticide intervention is a cost-effective strategy for long-term vector control.
• Mathematical modeling provides insights into optimizing public health interventions for vector-borne diseases.
• Heterogeneity does not negate the benefits of strategic, intensive initial control measures.