Comparing prioritization strategies for delivering indoor residual spray (IRS) implementation, using a network...

Area of Science:

• Vector-borne disease control
• Spatial epidemiology
• Public health resource allocation

Background:

• Indoor residual spraying (IRS) is a key malaria vector control method, complementing insecticide-treated nets.
• Limited funding necessitates balancing malaria risk with the cost of IRS implementation.
• This study developed a framework to model distances for IRS targeting in Zambia.

Purpose of the Study:

• To create a framework for modeling household distances for targeted IRS implementation.
• To apply this framework to prioritize IRS strategies in four Zambian provinces.
• To compare different malaria risk maps for IRS targeting.

Main Methods:

• Utilized optimal network models to calculate travel distances between operations bases and communities.
• Compared network distances with Euclidean distances to highlight the importance of road networks.
• Assessed IRS targeting for 50% of households using malaria risk maps (Plasmodium falciparum parasite rate and vector presence).

Main Results:

• Network route distances for IRS delivery ranged from 0.05 to 115.69 km.
• Euclidean distance inaccurately estimated network routes.
• Prioritization strategies showed minimal overlap, with less than 10% agreement on house inclusion/exclusion.
• Distances to prioritized communities were not statistically different from non-prioritized ones.

Conclusions:

• The distance to targeted communities varied significantly by risk prioritization strategy.
• Higher malaria risk did not correlate with greater remoteness.
• Findings suggest that high-burden malaria areas may not be more remote than lower-burden areas in Zambia.