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Table 2 Results from the mixed logistic model of the probability of a positive bacteriology result for non-reactor animals at the single intradermal tuberculin (SIT) test, interferon-gamma (IFN-γ) assay and both tests used in parallel from infected herds from Castilla y Leon, Spain

From: Risk factors associated with negative in-vivodiagnostic results in bovine tuberculosis-infected cattle in Spain

Dataset (n)

Variable

Class (n)

N

Number of T-/C + animals (%)

OR

P

Non-reactors if the severe SIT test and 0.05 IFN-γ assay are used in parallel: N = 927

Age

1st Q: 0.2-2

231

10 (4.3%)

1

NA

2nd Q: >2-4.8

231

22 (9.5%)

1.52 (0.61-3.78)

0.36

3rd Q: >4.8-8.5

233

29 (12.4%)

2.32 (0.97-5.53)

0.06

4th Q: >8.5-33.6

232

49 (21.1%)

3.89 (1.62-9.30)

0.002

Productive type

Beef

456

33 (7.2%)

1

NA

Dairy

286

18 (6.3%)

0.26 (0.07-1.06)

0.06

Bullfighting

185

59 (31.9%)

3.64 (1.38-9.59)

0.009

Number of herd tests

1

190

59 (31.1%)

1

NA

2

253

30 (11.9%)

0.58 (0.27-1.25)

0.17

3

342

14 (4.1%)

0.18 (0.08-0.43)

<0.001

4 or more

142

7 (4.9%)

0.07 (0.02-0.21)

<0.001

Non-reactors in the severe SIT test, N = 3,161

Age

1st Q: 0.2-1.7

790

88 (11.1%)

1

NA

2nd Q: >1.7-4.9

790

154 (19.5%)

1.42 (0.75-2.66)

0.28

3rd Q: >4.9-8.7

791

208 (26.3%)

3.68 (2.16-6.26)

<0.001

4th Q: >8.7-33.6

790

318 (40.3%)

6.59 (3.92-11.08)

<0.001

Productive type

Beef

1776

255 (14.4%)

1

NA

Dairy

512

30 (5.9%)

0.27 (0.06-1-17)

0.08

Bullfighting

873

483 (55.3%)

11.1 (5.10-24.1)

<0.001

Interaction age*productive type

Bullfighting *1st Q

164

58 (35.4%)

1

NA

Bullfighting *2nd Q

208

97 (46.6%)

1.28 (0.58-2.81)

0.56

Bullfighting *3rd Q

205

85 (41.5%)

0.53 (0.26-1.09)

0.08

Bullfighting *4th Q

296

102 (34.5%)

0.50 (0.25-0.99)

0.04

Number of herd tests

1

1268

534 (42.1%)

1

NA

2

850

134 (15.8%)

0.33 (0.25-0.44)

<0.001

3

641

46 (7.2%)

0.16 (0.11-0.24)

<0.001

4 or more

402

54 (13.4%)

0.23 (0.15-0.34)

<0.001

Non-reactors in the standard SIT test, N = 3,263

Age

1st Q: 0.2-1.7

816

89 (10.9%)

1

NA

2nd Q: >1.7-4.8

815

157 (19.3%)

1.44 (0.78-2.64)

0.24

3rd Q: >4.8-8.6

816

214 (26.2%)

3.80 (2.26-6.37)

<0.001

4th Q: >8.6-33.6

816

328 (40.2%)

6.39 (3.86-10.6)

<0.001

Productive type

Beef

1862

270 (14.5%)

1

NA

Dairy

522

30 (5.7%)

0.25 (0.06-1.10)

0.07

Bullfighting

879

488 (55.5%)

10.6 (4.95-22.8)

<0.001

Interaction age*productive type

Bullfighting *1st Q

164

58 (35.4%)

1

NA

Bullfighting *2nd Q

206

112 (54.4%)

1.30 (0.60-2.82)

0.51

Bullfighting *3rd Q

209

121 (57.9%)

0.50 (0.24-1.00)

0.05

Bullfighting *4th Q

300

197 (65.7%)

0.52 (0.26-1.02)

0.06

Number of herd tests

1

1316

551 (41.9%)

1

NA

2

868

136 (15.7%)

0.33 (0.25-0.44)

<0.001

3

663

46 (6.9%)

0.15 (0.10-0.23)

<0.001

4 or more

416

55 (13.2%)

0.24 (0.16-0.35)

<0.001

Non-reactors in the 0.05 IFN-γ assay: N = 1,129

Age

1st Q: 0.5-1.8

281

14 (5.0%)

1

NA

2nd Q: >1.8-4.6

284

31 (10.9%)

1.45 (0.68-3.08)

0.34

3rd Q: >4.6-8.1

281

41 (14.6%)

2.20 (1.07-4.51)

0.03

4th Q: >8.1-33.6

283

60 (21.2%)

2.86 (1.37-5.96)

0.005

Productive type

Beef

595

51 (8.6%)

1

NA

Dairy

324

22 (6.8)

0.25 (0.08-0.77)

0.02

Bullfighting

210

73 (34.8)

3.13 (1.49-6.54)

0.002

Number of herd tests

1

260

80 (30.8%)

1

NA

2

306

39 (12.7%)

0.55 (0.30-1.04)

0.06

3

387

18 (4.7%)

0.18 (0.09-0.36)

<0.001

4 or more

176

9 (5.1%)

0.09 (0.04-0.23)

0.059

Non-reactors in the 0.1 IFN-γ assay: N = 1,959

Age

1st Q: 0.5-1.9

488

30 (6.1%)

1

NA

2nd Q: >1.9-4.8

492

66 (13.4%)

1.76 (1.04-2.97)

0.03

3rd Q: >4.8-8.6

489

91 (18.6%)

2.58 (1.57-4.24)

<0.001

4th Q: >8.6-33.6

490

150 (30.6%)

4.98 (3.06-8.09)

<0.001

Productive type

Beef

1183

135 (11.4%)

1

NA

Dairy

370

25 (6.8%)

0.38 (0.15-0.98)

0.04

Bullfighting

406

177 (43.6%)

5.70 (3.14-10.3)

<0.001

Number of herd tests

1

654

209 (32.0%)

1

NA

2

535

70 (13.1%)

0.37 (0.25-0.56)

<0.001

3

517

34 (6.6%)

0.23 (0.14-0.38)

<0.001

4 or more

254

24 (9.5%)

0.21 (0.12-0.36)

<0.001

  1. Significant values are indicated in bold.
  2. *Indicates interaction between two variables.
  3. NA: Non-applicable.
  4. T-/C+: Animals negative in the in-vivo diagnostic test and positive in bacteriology.