Table 2 Characteristics of the locations of case households in the high and low transmission season of 2011 in Swaziland, compared against the characteristics of 10,000 population-weighted random background points
| Â | High season (Jan to Apr) | Low season (May to Dec) | Comparison of case locations between seasons | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Â | Cases | Background | t-test | df | p | Cases | Background | t-test | df | p | t-test | df | p |
N | 118 | 10,000 | Â | Â | Â | 44 | 10,000 | Â | Â | Â | Â | Â | Â |
Mean rainfall (mm) | 132.28 | 150.32 | 8.82 | 130 | 0.000 | 45.32 | 47.15 | 1.59 | 46 | 0.119 | −37.47 | 168 | 0.000 |
Summed rainfall (mm) | 529.11 | 601.28 | 8.82 | 130 | 0.000 | 362.58 | 377.22 | 1.59 | 46 | 0.119 | −13.62 | 118 | 0.000 |
Min rainfall (mm) | 46.80 | 63.40 | 14.10 | 134 | 0.000 | 7.04 | 3.45 | −6.47 | 46 | 0.000 | −31.11 | 163 | 0.000 |
Max rainfall (mm) | 182.72 | 198.60 | 6.45 | 130 | 0.000 | 98.67 | 103.24 | 0.74 | 46 | 0.466 | −12.62 | 61 | 0.000 |
Annual mean temperature (°C) | 21.57 | 19.40 | −24.04 | 137 | 0.000 | 21.42 | 19.40 | −11.42 | 47 | 0.000 | −0.73 | 70 | 0.470 |
Max temperature of warmest month (°C) | 30.69 | 28.06 | −21.43 | 134 | 0.000 | 30.42 | 28.06 | −10.60 | 47 | 0.000 | −1.07 | 75 | 0.288 |
Min temperature of coldest month (°C) | 8.79 | 7.47 | −16.39 | 133 | 0.000 | 9.13 | 7.47 | −8.73 | 47 | 0.000 | 1.67 | 63 | 0.099 |
Elevation (m) | 364.23 | 678.25 | 22.13 | 139 | 0.000 | 382.09 | 678.25 | 10.19 | 47 | 0.000 | 0.56 | 68 | 0.579 |
Topographic wetness index | 20.34 | 16.61 | −12.89 | 127 | 0.000 | 18.54 | 16.61 | −3.62 | 46 | 0.001 | −2.96 | 74 | 0.004 |
Landsat NDVI | 0.41 | 0.44 | 4.26 | 128 | 0.000 | 0.42 | 0.44 | 1.92 | 47 | 0.061 | 0.56 | 81 | 0.580 |
Landsat NDWI | −0.43 | −0.43 | 0.95 | 136 | 0.346 | −0.45 | −0.43 | 2.50 | 47 | 0.016 | −1.95 | 62 | 0.056 |
Distance to lake or irrigation | 6667 | 16,860 | 16.19 | 140 | 0.000 | 9298 | 16,860 | 4.31 | 47 | 0.000 | 1.42 | 58 | 0.161 |
Distance to river | 1424 | 1660 | 2.82 | 129 | 0.006 | 1380 | 1660 | 2.03 | 47 | 0.048 | −0.28 | 81 | 0.781 |
Population per 100Â m by 100 m cell | 1.48 | 11.64 | 17.11 | 597 | 0.000 | 1.80 | 11.64 | 9.05 | 66 | 0.000 | 0.30 | 61 | 0.764 |
IRS sprayed houses per person | 0.08 | 0.06 | −2.39 | 125 | 0.018 | 0.16 | 0.05 | −3.66 | 47 | 0.001 | 2.30 | 63 | 0.025 |
Nets per person | 44.78 | 14.25 | −1.30 | 123 | 0.197 | 10.42 | 0.11 | −2.57 | 47 | 0.013 | −1.44 | 130 | 0.152 |
Distance to imported case (m) | 9359 | 11,306 | 2.89 | 128 | 0.005 | 8827 | 10,781 | 2.54 | 48 | 0.014 | −0.52 | 120 | 0.602 |