Table 2.
Logistic regression of individual Strongylus vulgaris prevalence in Swedish horses against individual risk factors for infection.
| Investigated parameter | Odds ratio (95% aC.I.) | p-value | |
|---|---|---|---|
| Year of the study | 2016 | REF b | 0.15 |
| 2017 | 0.6 (0.3-1.2) | ||
| Region | South | REF | 0.67 |
| Central | 0.9 (0.4-2.1) | ||
| North | 0.6 (0.2-1.7) | ||
| Age group | 0-5 | REF | 0.84 |
| 6-10 | 0.7 (0.3-1.6) | ||
| 11-15 | 0.8 (0.3-1.6) | ||
| 16-20 | 0.8 (0.4-1.9) | ||
| >21 | 0.6 (0.2-1.5) | ||
| EPGc | <50 50-150 |
REF 0.7 (0.3-1.4) |
0.44 |
| 200-450 | 0.7 (0.3-1.5) | ||
| 500-800 | 1.3 (0.6-2.9) | ||
| ≥ 850 | 1.1 (0.5-2.6) | ||
| Time elapsed since deworming | 6 months | REF | 0.51 |
| 8 months | 0.6 (0.2-2.1) | ||
| 10 months | 0.6 (0.2-2.0) | ||
| 12 months | 0.7 (0.3-1.8) | ||
| 24 months | 1.7 (0.5-5.5) | ||
| 48 months | 1.1 (0.3-3.8) | ||
| Deworming routine | FECd | REF | 0.044 |
| FEC and cultivation for S. vulgaris | 0.3 (0.1-0.8) | ||
| Deworming 1-4 times/ year | 0.5 (0.2-1.3) | ||
| Colic last 24 months e | yes | REF | 0.94 |
| no | 1.0 (0.4-2.2) | ||
| S. vulgaris positive last 24 months | yes | REF | 0.13 |
| no | 1.9 (0.7-5.8) | ||
| not cultivated | 2.9 (1.0-8.9) |
aConfidence interval b reference sample used to calculate odds ratio within each investigated parameter c nematode eggs per gram d faecal egg count e if the horse had shown any signs of restlessness and pawing at the ground, irritated kicking to the stomach, rolling or attempting to roll during the last 24 months.