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Table 2 Apparent flock seroprevalence and odds of B. ovis exposure for risk factors in Wyoming, USA

From: Seroprevalence and risk factors of Brucella ovis in domestic sheep in Wyoming, USA

Risk Factor

N

Seroprevalencea

Odds Ratio (95% CI)

P value

Regionb

 Southeast

17

5.9% (1/17)

Reference

–

 Northwest

25

12.0% (3/25)

1.99 (0.21 to 60.81)

0.575

 Northeast

20

25.0% (5/20)

4.67 (0.62 to 134.15)

0.294

 West

6

16.7% (1/6)

3.01 (0.069 to 131.62)

0.575

 South-central

14

57.1% (8/14)

17.34 (2.39 to 502.01)

0.012

Flock Sizeb

 Small

24

4.2% (1/24)

Reference

–

 Very Small

20

10.0% (2/20)

2.36 (0.18 to 78.42)

0.516

 Medium

32

31.3% (10/32)

9.06 (1.51 to 237.89)

0.018

 Large

6

83.3% (5/6)

69.00 (5.81 to > 999.99)

< 0.001

Ewe-to-ram Ratio

 Medium

9

44.4% (4/9)

Reference

–

 Low

4

25.0% (1/4)

0.47 (0.01 to 6.07)

0.587

 High

4

75.0% (3/4)

3.21 (0.254 to 116.89)

0.587

Purchase of Outside Sheep

 No

7

28.6% (2/7)

Reference

–

 Yes

9

55.6% (5/9)

2.83 (0.35 to 32.03)

0.340

  1. aParenthesis indicate proportion of seropositive flocks per category
  2. bIndicates significant difference between seroprevalence by Fisher’s exact test at p < 0.05