TABLE 1.
Prevalence of virulence factors by farm and sample type
| Virulence factor | Farm | % prevalence by sample type (no. of samples)b |
||||||
|---|---|---|---|---|---|---|---|---|
| Overall farm | Fecal | Manure composite | Watera | Feed | Milk | Milk filter | ||
| eae | A | 63.8 (5,757) | 66.2 (4,538) | 89.3 (308) | 36.4 (121) | 62.6 (115) | 6.8 (365) | 80.6 (310) |
| B | 58.3 (4,736) | 64.3 (2,847) | 91.6 (629) | 22.2 (279) | 58.9 (207) | 4.3 (416) | 42.2 (358) | |
| C | 70.1 (2,834) | 76.3 (1,715) | 90.8 (412) | 26.4 (106) | 60.7 (84) | 13.4 (269) | 76.2 (248) | |
| stx1 | A | 29.3 (5,757) | 29.5 (4,538) | 63.0 (308) | 11.6 (121) | 24.3 (115) | 0.8 (365) | 35.2 (310) |
| B | 42.2 (4,736) | 47.3 (2,847) | 83.9 (629) | 6.5 (279) | 32.9 (207) | 0.5 (416) | 10.1 (358) | |
| C | 40.5 (2,834) | 41.9 (1,715) | 76.5 (412) | 8.5 (106) | 29.8 (84) | 1.9 (269) | 30.6 (248) | |
| stx2 | A | 28.0 (5,757) | 30.1 (4,538) | 55.8 (308) | 7.4 (121) | 20.0 (115) | 1.1 (365) | 12.6 (310) |
| B | 43.5 (4,736) | 53.2 (2,847) | 68.7 (629) | 11.8 (279) | 25.6 (207) | 0.5 (416) | 6.7 (358) | |
| C | 41.7 (2,834) | 47.1 (1,715) | 71.8 (412) | 7.5 (106) | 13.1 (84) | 0.7 (269) | 23.0 (248) | |
| γ-tirc | A | 13.5 (5,757) | 13.8 (4,538) | 30.8 (308) | 4.1 (121) | 2.6 (115) | 0.0 (365) | 15.2 (310) |
| B | 12.6 (4,736) | 11.2 (2,847) | 41.6 (629) | 3.2 (279) | 12.4 (207) | 0.0 (416) | 0.0 (358) | |
| C | 21.2 (2,834) | 21.4 (1,715) | 43.9 (412) | 4.3 (106) | 6.9 (84) | 0.7 (269) | 19.8 (248) | |
a
Water data in this table refer to trough water, across all age groups.
b
For the analysis shown in this table, samples with CT values of >35 were considered nondetects.
c
The number of samples analyzed for γ-tir was 5,756, 4,193, and 2,498 for farms A, B, and C, respectively, since in the first study year γ-tir was not tested in all samples.