Table 1 Categorical variables included in the bivariate analysis (chi-squared test with p < 0.2). Controls: 93 farms that remained brucellosis-free for at least three years. Cases: 98 herds previously free of brucellosis that became infected
From: Risk factors for new bovine brucellosis infections in Colombian herds
Variables | Control | Case | OR | 95% CI | ||
|---|---|---|---|---|---|---|
Lower | Upper | p-value | ||||
Livestock type | ||||||
Dairya | 68 (73.12%) | 60 (61.22%) | 1 | |||
Beef | 8 (8.60%) | 22 (22.45%) | 3.12 | 1.29 | 7.52 | 0.009 |
Dual purpose (beef and milk) | 17 (18.28%) | 16 (16.33%) | 1.07 | 0.5 | 2.29 | 0.869 |
Equipment shared with other farms | ||||||
Noa | 81 (87.10%) | 77 (78.57%) | 1 | |||
Yes | 12 (12.90%) | 21 (21.43%) | 1.84 | 0.85 | 4 | 0.12 |
Cleaning and disinfection of clinical equipment and clothing | ||||||
Yesa | 86 (92.47%) | 85 (86.73%) | 1 | |||
No | 7 (7.53%) | 13 (13.27%) | 1.88 | 0.72 | 4.94 | 0.197 |
Presence of facilities to shelter animals | ||||||
Noa | 41 (44.09%) | 31 (31.63%) | 1 | |||
Yes | 52 (55.91%) | 67 (68.37%) | 1.7 | 0.94 | 3.08 | 0.077 |
Farm fencing | ||||||
Completelya | 91 (97.85%) | 91 (92.86%) | 1 | |||
Partially | 2 (2.15%) | 7 (7.14%) | 3.5 | 0.71 | 17.3 | 0.105 |
Contact of the herd with other neighbouring farms | ||||||
Noa | 78 (83.87%) | 67 (68.37%) | 1 | |||
Yes | 15 (16.13%) | 31 (31.63%) | 2.41 | 1.2 | 4.83 | 0.012 |
Infected animals in the neighbouring herd | ||||||
Noa | 7 (7.53%) | 2 (2.04%) | 1 | |||
Yes | 86 (92.47%) | 96 (97.96%) | 3.91 | 0.79 | 19.32 | 0.074 |
Mixed farm (farms that have species other than buffaloes or cattle) | ||||||
Noa | 80 (86.02%) | 72 (73.47%) | 1 | |||
Yes | 13 (13.98%) | 26 (26.53%) | 2.22 | 1.06 | 4.648 | 0.032 |
Water access points shared with other farms b | ||||||
No farms or brucellosis-free farmsa | 59 (63.44%) | 48 (48.98%) | 1 | |||
Non-brucellosis-free farms | 34 (36.56%) | 50 (51.02%) | 1.81 | 1.01 | 3.22 | 0.045 |
Presence of drainage from other farms | ||||||
Noa | 58 (62.37%) | 48 (48.98%) | 1 | |||
Yes | 35 (37.63%) | 50 (51.02%) | 1.73 | 0.97 | 3.07 | 0.063 |
Animal movement: Brucella status b of other herds at the destination | ||||||
Brucellosis-free farms or no movementa | 89 (95.70%) | 87 (88.78%) | 1 | |||
Non-brucellosis-free farms | 4 (4.30%) | 11 (11.22%) | 2.81 | 0.86 | 9.17 | 0.076 |
Status of the origin of replacement animalsb (internal or brucellosis-free farms vs calves from non-brucellosis-free farms) | ||||||
Brucellosis-free farms or internala | 85 (91.40%) | 67 (68.37%) | 1 | |||
Non-brucellosis-free farms | 8 (8.60%) | 31 (31.63%) | 4.92 | 2.12 | 11.39 | < 0.001 |
Internal replacement with calves from the same farm whose mothers were positive | ||||||
Noa | 89 (95.70%) | 78 (79.59%) | 1 | |||
Yes | 4 (4.30%) | 20 (20.41%) | 5.71 | 1.87 | 17.41 | 0.001 |
Introduction of heifers < 24 months old into the farm | ||||||
No admittancea | 79 (84.95%) | 72 (73.47%) | 1 | |||
Admittance | 14 (15.05%) | 26 (26.53%) | 2.04 | 0.99 | 4.2 | 0.052 |
Number of cattle introduced into the farm (per year) | ||||||
Nonea | 66 (70.97%) | 53 (54.08%) | 1 | |||
Ten or fewer | 19 (20.43%) | 23 (23.47%) | 1.51 | 0.74 | 3.06 | 0.255 |
Between eleven and thirty | 6 (6.45%) | 10 (10.20%) | 2.08 | 0.71 | 6.08 | 0.178 |
More than thirty | 2 (2.15%) | 12 (12.25%) | 7.47 | 1.6 | 34.85 | 0.004 |
Infection status of the origin of the cattle b (of all ages) | ||||||
Tested negative for Brucella or brucellosis-free farma | 71 (76.34%) | 58 (59.18%) | 1 | |||
Not tested, unknown status of the farm, positive herds | 22 (23.66%) | 40 (40.82%) | 2.23 | 1.19 | 4.16 | 0.012 |
Introduction of other domestic species into the farm | ||||||
Nonea | 88 (94.63%) | 85 (86.74%) | 1 | |||
More than twenty | 0 (0.0%) | 3 (3.06%) | 7.25 | 0.37 | 142.37 | 0.13 |
Less than or equal to twenty | 5 (5.37%) | 10 (10.20%) | 2.07 | 0.68 | 6.31 | 0.194 |
Brucella status b of the origin of the bulls | ||||||
Artificial inseminationa | 36 (38.71%) | 34 (34.69%) | 1 | |||
Free herds | 44 (47.31%) | 16 (16.33%) | 0.39 | 0.18 | 0.81 | 0.011 |
Unknown/positive status | 13 (13.98%) | 48 (48.98%) | 3.91 | 1.81 | 8.46 | < 0.001 |
Access of dogs and cats to/contact with aborted foetuses and reproductive discharges | ||||||
No (or no dogs)a | 66 (70.97%) | 59 (60.20%) | 1 | |||
Yes | 27 (29.03%) | 39 (39.80%) | 1.62 | 0.88 | 2.95 | 0.119 |