A spatially structured mixed vector control strategy.

<p>The proposed mixed strategy involves vertical control targeted at areas of predicted high risk of domestic infestation clustering (circles and solid lines) and horizontal control based on community participation in the communities predicted to be at medium to low risk (squares and dashed lines).</p

Risk maps of <i>T. infestans</i> domestic infestation.

<p>(A) Map showing the predicted prevalence of domestic infestation. (B) Map showing the probability of membership in a cluster of high domestic infestation. Both maps were estimated from the coefficients of the best fitting models. The spatial resolution of the map is 1×1 km.</p

Assessing the costs of spraying communities predicted to be at high-risk of domestic infestation clustering.

1<p>Assumes all communities are visited. Blanket control is performed based on the rule of contiguity (i.e. the nearest neighbor first). Targeted control assumes only communities predicted as high-risk (from the risk map) are visited.</p>2<p>Refers to the city where spraying brigades are based.</p>3<p>Communities with prevalence of domestic infestation by <i>T. infestans</i> higher than 10% are slated for blanket spraying (Tintina = 66 communities and 880 houses; Quimili = 76 communities and 822 houses).</p>4<p>Selected from communities estimated in 3.</p>5<p>The total cost for a Blanket contiguous strategy was estimated to be US$69,779 and for a Targeted strategy US$35,552. Costs were based on Vazquez-Prokopec et al. 2009 <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001788#pntd.0001788-VazquezProkopec1" target="_blank">[5]</a> estimates and include cost of insecticides (US$6.9 per sprayed house), salaries (US$22 per-diem and US$11.2 wages per technician per day) and mobility (US$1 per km).</p

Spatial distribution of <i>T. infestans</i> domestic infestation.

<p>Prevalence of domestic infestation by <i>T. infestans</i> (assessed by householders' collections) during 1999–2002 in the Moreno Department, Santiago del Estero, Argentina. ND refers to communities for which infestation data were not available.</p

Factors associated with membership of a community in a cluster of high <i>T. infestans</i> infestation in the Moreno Department, Santiago del Estero, Argentina.

1<p>Variables: Den, density of rural houses (# per sq. km); Dist, distance from a community to the nearest T. infestans infested community (meters); LST, mean maximum land surface temperature (°C); NDVI, Normalized Difference Vegetation Index (no units); Elev, mean elevation of each community (meters above sea level); Deg, percentage of landscape within 2 km of a village that was degraded (see text for details); Def, percentage of landscape within 2 km of a community that was deforested (see text for details); Crops, percentage of landscape within 2 km of a village that was modified for soy production.</p><p>Symbols: X (variable tested in model); — (variable not tested in model); − (negative association) + (positive association);</p>**<p>(<i>P</i>≤0,01);</p>*<p>(0,01<<i>P</i>≤0,05); NS (not significant).</p><p>Δ_i = AIC_i−AIC_min.</p><p>ω_i = exp (−1/2 Δ_i)/Σ exp (−1/2 Δ_i).</p><p>Σ ω_i(<i>j</i>): sum of ω_i values from every model in which variable <i>i</i> was present. Indicates the relative importance of each independent variable in predicting the data.</p>2<p>Lowest AIC = 60.8.</p

Factors associated with the high prevalence of domestic infestation by <i>T. infestans</i> in the Moreno Department, Santiago del Estero, Argentina.

1<p>Variables: Den, density of rural houses (# per sq. km); Dist, distance from a community to the nearest T. infestans infested community (meters); LST, mean maximum land surface temperature (°C); NDVI, Normalized Difference Vegetation Index (no units); Elev, mean elevation of each community (meters above sea level); Deg, percentage of landscape within 2 km of a village that was degraded (see text for details); Def, percentage of landscape within 2 km of a community that was deforested (see text for details); Crops, percentage of landscape within 2 km of a village that was modified for soy production.</p><p>Symbols: X (variable tested in model); — (variable not tested in model); − (negative association) + (positive association);</p>**<p>(<i>P</i>≤0,01);</p>*<p>(0,01<<i>P</i>≤0,05); NS (not significant).</p><p>Δ_i = AIC_i−AIC_min.</p><p>ω_i = exp (−1/2 Δ_i)/Σ exp (−1/2 Δ_i).</p><p>Σ ω_i(<i>j</i>): sum of ω_i values from every model in which variable <i>i</i> was present. Indicates the relative importance of each independent variable in predicting the data.</p>2<p>Lowest AIC = 701.8.</p

Spatially explicit insecticide spraying schemes in the Moreno Department.

<p>(A) Implementation of a spatially contiguous strategy (i.e., visiting the nearest neighbor of each community). (B) Strategy targeting interventions according to risk (i.e., only high-risk communities are treated). Color squares indicate the location of Moreno's main cities (Quimili in pink and Tintina in light blue) where spraying teams initiate their journeys. Spraying was performed by two trucks (one stationed on each city) with two technicians each (represented by lines of the same color as the square indicating the city where they are based at). Black circles indicate the communities first visited by each spraying team in each control scenario.</p