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Table 1 Univariable logistic regression of farm-based factors associated with serological Q fever infection on farm level

From: Seroprevalence and risk factors of Q fever in goats on commercial dairy goat farms in the Netherlands, 2009-2010

Variable Category N (%) Prev(%) OR 95% CI P-value
Herd size
(number of goats according to UBN registry)
≥ 800 47 (49.0) 59.6 3.7 1.6-8.6 0.0020
  < 800 49 (51.0) 28.6 Ref   
Mandatory vaccination area 2009 Inside 53 (55.2) 58.5 4.1 1.7-9.9 0.0010
  Outside 43 (44.8) 25.6 Ref   
Goat density per km2
within 5 km radius from farm
≥ 25 48 (50.0) 56.3 2.8 1.2-6.5 0.0130
  < 25 48 (50.0) 31.3 Ref   
Cattle density per km2
in farm municipality (excl. meat calves)
≥ 100 67 (69.8) 50.8 2.7 1.1-7.0 0.0329
  < 100 29 (30.2) 27.6 Ref   
Distance to nearest bulk milk PCR-positive farm
(km)
0- < 4 29 (30.2) 72.4 10.0 3.4-29.1 < .0001
  4- < 8 19 (19.8) 57.9 5.2 1.7-16.5  
  ≥ 8 48 (50.0) 20.8 Ref   
Number of stables 1-2 stables 40 (41.7) 35.0 Ref   0.1424
  ≥ 3 stables 56 (58.3) 50.0 1.9 0.8-4.3  
Use of artificial insemination Yes 26 (27.1) 61.5 2.7 1.1-6.7 0.0370
  No 70 (72.9) 37.7 Ref   
Having at least one dog at the farm Yes 84 (87.5) 47.6 4.6 0.9-22.0 0.0337
  No 12 (12.5) 16.7 Ref   
Having at least one rabbit at the farm Yes 26 (27.1) 30.8 0.5 0.2-1.2 0.1138
  No 70 (72.9) 48.6 Ref   
Having at least one pet bird at the farm Yes 25 (25.0) 28.0 0.4 0.2-1.1 0.0606
  No 71 (75.0) 49.3 Ref   
Dog(s) in goat stable Yes 60 (62.5) 51.7 2.4 1.0-5.8 0.0415
  No/unknown 36 (37.5) 30.6 Ref   
Cat(s) in goat stable Yes 34 (35.4) 58.8 2.6 1.1-6.1 0.0275
  No/unknown 62 (64.6) 35.5 Ref   
Signs of vermin (mice, rats, birds)
in roughage or litter during past 12 months
Unknown 14 (14.6) 64.3 2.7 0.8-8.7 0.0944
  Known (yes or no) 82 (85.4) 40.2 Ref   
Feeding silage Yes 64 (66.7) 51.6 2.7 1.1-6.8 0.0269
  No 32 (33.3) 28.1 Ref   
Feeding maize Yes 40 (41.7) 55.0 2.2 1.0-5.0 0.0602
  No 56 (58.3) 35.7 Ref   
Use of lucerne, pulp feed
or other roughage/litter
Yes 24 (25.0) 58.3 2.2 0.9-5.6 0.0972
  No 72 (75.0) 38.9 Ref   
Origin of straw Abroad/unknown 59 (61.5) 49.2 1.8 0.8-4.2 0.1757
  No straw or domestic straw 37 (38.5) 35.1 Ref   
Feeding method Hand/wheelbarrow 31 (32.3) 22.6 Ref   0.0202
  Fodder mixer 56 (58.3) 57.1 4.6 1.7-12.4  
  Automatic 9 (9.4) 33.3 1.7 0.3-8.7  
Sidewall ventilation Yes 38 (39.6) 34.2 0.5 0.2-1.2 0.1252
  No 58 (60.4) 50.0 Ref   
Control nuisance animals
(e.g. wild birds) in 2008
Yes, by covering air spaces 15 (15.6) 73.3 2.1 1.3-15.4 0.0409
  Yes, only via another ways
(a.o. capture cage)
13 (13.5) 38.5 1.0 0.3-3.4  
  Not applicable 68 (70.8) 38.2 Ref   
Percentage of aborting goats or goats with stillbirth
in 2007-2009 or known history of abortion wave
due to Q fever since 2005
< 4% 82 (85.4) 39.0 Ref   0.0234
  ≥ 4% and/or abortion wave 14 (14.6) 71.4 3.9 1.1-13.5  
Spread of manure On or near own farmland 79 (82.3) 39.2 Ref   0.0497
  To other places 15 (15.6) 66.7 3.1 1.0-9.9  
Lambing periods in 2009 ≤ 1 57 (59.4) 31.6 Ref   0.0035
  ≥ 2 39 (40.6) 61.5 3.5 1.5-8.1  
Type of tenure Completely closed 27 (28.1) 55.6 2.4 0.9-6.1 0.1158
  Closed for female goats only 52 (54.2) 34.6 Ref   
  No, not closed 16 (16.7) 56.3 2.4 0.8-7.6  
Goat supply from the province of Friesland Yes 19 (19.6) 26.3 0.4 0.1-1.2 0.0806
  No 77 (80.2) 48.1 Ref   
Goat supply from the province of Overijssel Yes 10 (10.4) 20.0 0.3 0.1-1.4 0.0961
  No 86 (89.6) 46.5 Ref   
  1. Frequency (N), prevalence (Prev), odds ratio (OR), and 95% confidence interval (95%CI) of variables with Likelihood ratio test P values < 0.20 (96 farms, 43.1% positive farms based on total sample of 123 farms and 2,828 goats)