Table 1. Descriptive statistics for the variables analyzed in the four study sites.
| Lower-Northern Thailand | Red River Delta, Vietnam | Vietnam highlands | Lake Alaotra, Madagascar | |
| Median (IQRa) | Median (IQR) | Median (IQR) | Median (IQR) | |
| Chicken density (birds/km2) | 261.2 (121.4–570.7) | 2836.0 (1983.0–3532.0) | 146.9 (79.7–239.6) | 10.9 (10.3–46.6) |
| Duck density (birds/km2) | 4.2 (0.1–40.5) | 663.8 (497.2–978.7) | 29.5 (16.2–75.9) | 9.2 (4.6–11.8) |
| Percentage of rice fields | 0.5 (0.2–0.7) | 1 (0.5–1) | 0.2 (0–0.4) | 0.4 (0.2–0.8) |
| Water distance (m) | 265.9 (113.7–690.1) | 1691.0 (811.7–2671.0) | 8948.0 (4098.0–15500.0) | 740.2 (250.6–2195.0) |
| Road distance (m) | 3300.0 (852.5–6724.0) | 3728.0 (1533.0–5909.0) | 7897.0 (2838.0–16600.0) | 594.5 (377.3–3385.0) |
| Human population density (persons/km2) | 100.4 (70.3–116.0) | 799.8 (573.6–975.1) | 83.9 (55.6–110.4) | 38.2 (36.9–53.3) |
a
interquartile range.