Table 1. Association between invasion time of scrub typhus and influencing factors at the county level in survival analysis, from 2006 to 2013. The invasion time denotes the interval from the year when the first human case of scrub typhus was confirmed to the year of 2006.
| Variables | Univariate Cox analysis | Multivariate Cox analysis | ||
|---|---|---|---|---|
| Crude HR (95% CI) | P-value | Adjusted HR (95% CI) | P-value | |
| Distance to the nearest epidemic county | 0.74 (0.70, 0.78) | <.001 | NS (excluded) | |
| Intersected by national highway | 1.12 (0.95, 1.31) | .175 | ||
| Intersected by freeway | 1.82 (1.54, 2.13) | <.001 | 1.31(1.11, 1.54) | .001 |
| The proportion of flow population | 1.03 (1.01, 1.04) | .001 | NS (excluded) | |
| Coverage percentage of coniferous forest | 1.23 (1.18, 1.29) | <.001 | NS (excluded) | |
| Coverage percentage of mixed broadleaf-conifer forest | 0.96 (0.87, 1.05) | .368 | NS (excluded) | |
| Coverage percentage of broadleaf forest | 1.29 (1.25, 1.34) | <.001 | 1.10 (1.06, 1.15) | <.001 |
| Coverage percentage of shrub | 1.08 (1.03, 1.14) | .004 | NS (excluded) | |
| Coverage percentage of grassland | 0.74 (0.69, 0.80) | <.001 | NS (excluded) | |
| Percentage coverage of dry field | 0.90 (0.87, 0.93) | <.001 | NS (excluded) | |
| Percentage coverage of paddy field | 1.18 (1.14, 1.22) | <.001 | NS (excluded) | |
| Monthly cumulative precipitation | 1.33 (1.30, 1.37) | <.001 | NS (excluded) | |
| Monthly average temperature | 1.29 (1.27, 1.32) | <.001 | 1.27 (1.25, 1.30) | <.001 |
| Monthly average relative humidity | 1.85 (1.76, 1.95) | <.001 | NS (excluded) | |
| Monthly average sunshine hours | 0.31 (0.26, 0.38) | <.001 | NS (excluded) | |