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Table I.
Results of the univariate analysis of potential risk factors for the 2006/2007 HPAI outbreak period in the Mekong Delta of Viet Nam.
| Variable | Categories | Odds Ratio | 95% CI | P |
|---|---|---|---|---|
| River length within a commune (in km) | < 0.001 | |||
| ≤ 8.18 | 1 | |||
| 8.18–20.6 | 2.19 | 0.97–4.92 | ||
| ≥ 20.7 | 4.73 | 2.24–9.97 | ||
| Major road length within a commune (in km) | 0.019 | |||
| ≤ 0.00 | 1 | |||
| 0.01–3.51 | 0.49 | 0.22–1.10 | ||
| ≥ 3.52 | 1.42 | 0.83–2.44 | ||
| Re-scaled NDVI annual mean | 0.027 | |||
| ≤ 145.40 | 1 | |||
| 145.41–163.14 | 2.36 | 1.23–4.54 | ||
| ≥ 163.15 | 1.55 | 0.77–3.10 | ||
| Re-scaled NDVI annual median | 0.016 | |||
| ≤ 147.15 | 1 | |||
| 147.16–164.00 | 2.37 | 1.24–4.54 | ||
| ≥ 164.01 | 1.48 | 0.73–3.02 | ||
| Re-scaled NDVI mean May–October | 0.002 | |||
| ≤ 141.14 | 1 | |||
| 141.15–166.15 | 1.8 | 1.01–3.21 | ||
| ≥ 166.16 | 0.58 | 0.28–1.22 | ||
| Re-scaled NDVI median May–October | 0.004 | |||
| ≤ 144.00 | 1 | |||
| 144.01–168.00 | 1.79 | 1.00–3.18 | ||
| ≥ 168.01 | 0.61 | 0.29–1.27 | ||
| Re-scaled NDVI mean November–April | 0.005 | |||
| ≤ 148.22 | 1 | |||
| 148.23–170.79 | 0.5 | 0.27–0.91 | ||
| ≥ 170.80 | 0.38 | 0.20–0.73 | ||
| Re-scaled NDVI median November–April | 0.007 | |||
| ≤ 148.00 | 1 | |||
| 148.01–171.03 | 0.42 | 0.22–0.78 | ||
| ≥ 171.04 | 0.47 | 0.26–0.86 | ||
| Number of households | 0.002 | |||
| ≤ 1995.00 | 1 | |||
| 1995.01–3009.52 | 2.76 | 1.31–5.83 | ||
| ≥ 3009.53 | 3.24 | 1.55–6.77 | ||
| Population | < 0.001 | |||
| ≤ 9768.00 | 1 | |||
| 9768.01–14683.00 | 2.07 | 0.95–4.51 | ||
| ≥ 14683.01 | 3.98 | 1.94–8.19 | ||
| Population density (per km2) | < 0.001 | |||
| ≤ 308.00 | 1 | |||
| 308.01–652.35 | 0.43 | 0.24–0.75 | ||
| ≥ 652.36 | 0.13 | 0.05–0.31 | ||
| Proportion of females | 0.037 | |||
| ≤ 0.51 | 1 | |||
| 0.51–0.52 | 0.88 | 0.50–1.55 | ||
| ≥ 0.52 | 0.44 | 0.22–0.87 | ||
| Proportion of young (≤ 14 years) | < 0.001 | |||
| ≤ 0.32 | 1 | |||
| 0.33–0.35 | 2.88 | 1.26–6.59 | ||
| ≥ 0.36 | 4.98 | 2.27–10.91 | ||
| Proportion of working age (15–65 years) | 0.001 | |||
| ≤ 0.61 | 1 | |||
| 0.62–0.63 | 0.73 | 0.42–1.27 | ||
| ≥ 0.64 | 0.29 | 0.14–0.60 | ||
| Proportion of old (> 65 years) | < 0.001 | |||
| ≤ 0.04 | 1 | |||
| 0.05–0.059 | 0.45 | 0.26–0.79 | ||
| ≥ 0.06 | 0.11 | 0.04–0.27 | ||
| Average No. of persons per household | < 0.001 | |||
| ≤ 4.77 | 1 | |||
| 4.78–5.02 | 2.57 | 0.98–6.72 | ||
| ≥ 5.03 | 8.66 | 3.63–20.65 | ||
| Proportion households with electricity | < 0.001 | |||
| ≤ 0.26 | 1 | |||
| 0.27–0.53 | 0.22 | 0.11–0.43 | ||
| ≥ 0.54 | 0.22 | 0.11–0.44 | ||
| Proportion households with TV | 0.004 | |||
| ≤ 0.43 | 1 | |||
| 0.44–0.56 | 3.05 | 1.50–6.18 | ||
| ≥ 0.57 | 2.29 | 1.10–4.76 | ||
| Proportion households with a radio | 0.007 | |||
| ≤ 0.45 | 1 | |||
| 0.46–0.53 | 2.69 | 1.31–5.51 | ||
| ≥ 0.54 | 2.6 | 1.27–5.36 | ||
| Proportion of people below poverty line (as defined by Minot and Goletti 2000, [7]) | < 0.001 | |||
| ≤ 0.37 | 1 | |||
| 0.38–0.46 | 1.6 | 0.92–2.78 | ||
| ≥ 0.47 | 0.33 | 0.15–0.75 | ||
| Percentage of agricultural land | < 0.001 | |||
| ≤ 76.78 | 1 | |||
| 76.79–80.89 | 0.11 | 0.33–0.36 | ||
| ≥ 80.90 | 1.31 | 0.78–2.21 | ||
| Area used for aquaculture (per km2 of total land) | < 0.001 | |||
| ≤ 2.42 | 1 | |||
| 2.43–56.90 | 3 | 0.62–14.55 | ||
| ≥ 59.91 | 45.85 | 11.06–190.14 | ||
| Paddy yield (Quintal per ha) | < 0.001 | |||
| ≤ 44.30 | 1 | |||
| 44.31–46.95 | 0.04 | 0.02–0.11 | ||
| ≥ 46.96 | 0.06 | 0.02–0.15 | ||
| Sweet potato yield (Quintal per ha) | < 0.001 | |||
| ≤ 124 | 1 | |||
| 125–202 | 0.08 | 0.03–0.18 | ||
| ≥ 203 | 0.06 | 0.2–0.26 | ||
| Maize yield (Quintal per ha) | < 0.001 | |||
| ≤ 36 | 1 | |||
| 37–43 | 15.58 | 5.49–44.20 | ||
| ≥ 44 | 8.6 | 2.94–25.19 | ||
| Income (average per household) (in Vietnamese Dong) | < 0.001 | |||
| ≤ 737 000 | 1 | |||
| 738 000–802 000 | 1.5 | 0.88–2.57 | ||
| ≥ 803 000 | 0.19 | 0.07–0.50 | ||
| Pig density (No. per km2) | < 0.001 | |||
| ≤ 0.53 | 1 | |||
| 0.54–0.96 | 0.97 | 0.57–1.63 | ||
| ≥ 0.97 | 0.1 | 0.03–0.34 | ||
| Cattle density (No. per km2) | < 0.001 | |||
| ≤ 0.02 | 1 | |||
| 0.03–0.13 | 0.95 | 0.56–1.61 | ||
| ≥ 0.14 | 0.55 | 0.13–0.23 | ||
| Buffalo density (No. per km2) | < 0.001 | |||
| ≤ 0.00 | 1 | |||
| 0.01–0.02 | 0.1 | 0.04–0.25 | ||
| > 0.02 | 1.16 | 0.66–2.01 | ||
| Percentage of urban land use per total area of commune | 0.009 | |||
| ≤ 0.00 | 1 | |||
| ≥ 0.01 | 0.38 | 0.02–0.85 | ||
| Proportion of chicken farms | 0.001 | |||
| ≤ 0.47 | 1 | |||
| 0.48–0.66 | 0.67 | 0.39–1.14 | ||
| ≥ 0.67 | 0.23 | 0.09–0.56 | ||
| Poultry farm all density (No. farms per km2) | < 0.001 | |||
| ≤ 0.93 | 1 | |||
| 0.94–1.50 | 0.13 | 0.02–0.09 | ||
| ≥ 1.51 | 0.89 | 0.04–0.19 | ||
| Poultry flock density (No. of flocks > 50 heads per km2) | < 0.001 | |||
| ≤ 0.57 | 1 | |||
| 0.58–1.14 | 1.64 | 0.97–2.76 | ||
| ≥ 1.15 | 0.13 | 0.04–0.43 | ||
| Slaughter liveweight density (t per km2) | < 0.001 | |||
| ≤ 0.92 | 1 | |||
| 0.93–3.45 | 0.5 | 0.30–0.85 | ||
| ≥ 3.46 | 0.07 | 0.02–0.15 | ||
| Egg production density (No. per km2) | < 0.001 | |||
| ≤ 36 956.29 | 1 | |||
| 36 956.30–75 451.56 | 0.12 | 0.06–0.23 | ||
| ≥ 75 451.57 | 0.04 | 0.01–0.15 |