Table 4. Univariate logistic model of farm-based characteristics associated with Coxiella burnetii positivity among dairy cattle farm residents, the Netherlands, September 2010–March 2011*.
| Variable | No. residents total (% positive) | OR (95% CI) |
|---|---|---|
| No. cows on farm in 2008†‡ |
755 (72.1) |
1.0 (1.0–1.0) |
| Nearest bulk tank milk positive small-ruminant farm† | ||
| <8 km | 331 (75.8) | 1.4 (1.0–1.9) |
|
>8 km |
424 (69.1) |
Reference |
| Municipal cattle density, including beef calves§ |
755 (72.1) |
1.0 (1.0–1.0) |
| Farm location | ||
| Inside small-ruminant vaccination area | 202 (78.2) | 1.6 (1.0–2.3) |
| Outside small-ruminant vaccination area |
553 (69.8) |
Reference |
| Farm region† | ||
| South | 170 (80.6) | 1.8 (1.2–2.7) |
| Other |
585 (69.6) |
Reference |
| Beef cattle on the farm† | ||
| Yes | 79 (82.3) | 1.9 (1.1–3.4) |
| No |
652 (70.7) |
Reference |
| Annual peak in calving | ||
| Yes | 135 (76.3) | 1.3 (0.9–2.0) |
| No |
601 (71.1) |
Reference |
| Automatic milking† | ||
| Yes | 154 (65.6) | 0.7 (0.5–1.0) |
| No |
580 (73.8) |
Reference |
| Use of bedding in stables | ||
| Yes | 717 (72.4) | 1.9 (1.2–2.9) |
| No |
19 (57.9) |
Reference |
| Pet cat | ||
| Yes | 444 (69.1) | 0.6 (0. 5–0.9) |
| No |
285 (77.9) |
Reference |
| Pet rabbit | ||
| Yes | 202 (64.4) | 0.6 (0.4–0.8) |
| No |
527 (75.7) |
Reference |
| Birds in stable† | ||
| Yes | 90 (82.2) | 1.9 (1.0–3.6) |
| No |
644 (70.5) |
Reference |
| Use of by-product feedstuffs† | ||
| Yes | 229 (77.3) | 1.5 (1.0–2.1) |
| No |
507 (69.6) |
Reference |
| No. cows that calved in 2009‡ | 720 (71.8) | 1.0 (1.0–1.0) |
| No. live-born calves | ||
| <78 | 335 (69.0) | Reference |
| >78 | 344 (74.1) | 1.3 (0.9–1.8) |
| No. twin calves | ||
| 1–2 | 272 (69.9) | Reference |
|
>3 |
313 (76.4) |
1.4 (1.0–2.0) |
| Type of farm management† | ||
| Closed herd | 515 (73.4) | Reference |
| Purchase of cattle |
213 (68.1) |
0.8 (0.6–1.1) |
| No. cattle purchase addresses in 2007† | ||
| 0 or 1 | 649 (72.7) | Reference |
|
>2 |
76 (64.5) |
0.7 (0.4–1.0) |
| Farm boots and work clothes available for professional visitors | ||
| Yes | 662 (71.3) | 0.7 (0.4–1.1) |
| No |
74 (78.4) |
Reference |
| Work clothes available for own personnel | ||
| Yes | 556 (73.6) | 1.4 (1.0–1.9) |
| No | 180 (67.2) | Reference |
*The analysis included the primary farm-based factors associated with positivity (p<0.20 in likelihood ratio test). OR, odds ratio. †Variable included in later multivariate analysis before manual backward elimination. ‡Risk increases per cow. §Risk decreases per cow.