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Table 3 Univariable logistic regression of farm-based factors associated with serological Q fever infection on animal 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 (according to UBN registry) < 800 1164 13.8 Ref   0.0017
  ≥ 800 1013 30.2 3.3 1.6-7.0  
Mandatory vaccination area Inside 1116 28.2 3.3 1.5-7.3 0.0042
  Outside 1061 14.3 Ref   
Goat density per km2 in 5 km radius from the farm < 25 1167 18.2 Ref   0.0805
  ≥ 25 1010 25.3 1.9 0.9-3.9  
Cattle density per km2 in farm municipality (excl. meat calves) < 100 643 11.2 Ref   0.0084
  ≥ 100 1534 25.8 3.5 1.4-8.9  
Distance to nearest bulk milk PCR-positive farm (km) 0- < 4 688 37.8 5.0 2.2-11.6 < .0001
  4- < 8 400 25.3 3.2 1.1-8.9  
  ≥ 8 1089 9.7 Ref   
Anglo-Nubian goat Present 402 11.9 0.5 0.2-1.1 0.0694
  Absent 1775 23.6 Ref   
Number of stables 1-2 stables 983 14.2 Ref   0.0046
  ≥ 3 stables 1194 27.4 3.0 1.4-6.5  
Use of artificial insemination Yes 572 34.6 2.7 1.3-5.6 0.0181
  No 1585 17.0 Ref   
Presence of laying hens at the farm Yes 359 8.9 0.3 0.1-0.9 0.0184
  No 1818 23.9 Ref   
Having at least one dog at the farm Yes 1927 23.5 Ref   0.0530
  No 250 5.6 0.2 0.0-1.0  
Having at least one rabbit at the farm Yes 608 6.4 0.2 0.1-0.6 0.0008
  No 1569 27.3 Ref   
Having at least one pet bird at the farm Yes 501 9.4 0.3 0.1-0.9 0.0132
  No 1676 25.1 Ref   
Cat(s) in goat stable Yes 786 24.2 1.7 0.8-3.4 0.1718
  No/unknown 1391 19.9 Ref   
Signs of vermin (mice, rats, birds) in roughage or litter during past 12 months Unknown 364 41.8 2.8 1.2-6.2 0.0471
  Yes or No 1813 17.4 Ref   
Feeding silage Yes 1498 26.1 Ref   0.0218
  No 679 11.2 0.4 0.2-0.9  
Feeding maize Yes 872 28.8 Ref   0.0333
  No 1305 16.6 0.5 0.2-0.9  
Use of lucerne, pulp feed or other roughage/litter Yes 505 28.1 1.8 0.9-3.7 0.1445
  No 1672 19.4 Ref   
Feeding method With hand/wheelbarrow 772 13.5 0.3 0.1-0.9 0.0299
  With fodder mixer 1191 27.0 Ref   
  Automatic 214 19.6 0.5 0.1-1.9  
Type of ventilation system of stables Mechanic ventilation 593 30.5 2.0 1.0-4.3 0.0899
  No mechanic ventilation 1584 18.1 Ref   
Use of windbreak curtain and/or windshields Windbreak curtain 799 30.5 3.7 1.5-9.3 0.0198
  Only wind shields 937 18.8 1.6 0.6-4.3  
  None 441 10.7 Ref   
Presence of nuisance animals (e.g. wild birds) in the stable Yes, many 388 12.6 0.6 0.2-2.0 0.1206
  Yes, few 880 27.3 1.7 0.8-3.7  
  No 889 20.0 Ref   
Combat of nuisance animals (e.g. wild birds) in 2008 Via covering air spaces 349 38.7 3.0 1.4-6.3 0.0721
  Yes, only via other ways (e.g. capture cage) 274 21.2 1.3 0.4-4.3  
  Not applicable 1554 17.6 Ref   
Spread of manure To other places/not applicable 352 30.7 2.1 1.0-4.7 0.1076
  On farmland or near environment 1825 19.7 Ref   
Lambing periods in 2009 ≤ 1 1351 15.6 Ref   0.0039
  > 1 826 31.0 3.0 1.5-6.1  
Percentage of aborting goats or goats with stillbirth in 2007-2009
or known history of abortion wave due to Q fever since 2005
< 4% 1882 18.4 Ref   0.0251
  ≥ 4% 295 40.7 3.4 1.5-7.6  
Type of Tenure Completely closed 590 29.5 2.3 1.0-5.0 0.0898
  Only closed for female goats 1217 16.1 Ref   
  Not closed 349 27.8 2.2 0.8-5.6  
Provinces where supplied animals originated Provinces of Friesland and/or Overijssel 639 8.0 0.3 0.1-0.7 0.0028
  Supply from other provinces or no supply 1538 27.1 Ref   
  1. Factors associated with Q fever with their frequency (N), animal prevalence (Prev), odds ratio (OR), and 95% confidence intervals (95% CI) with P value of the univariable generalized linear regression < 0.20 on animal level accounting for random herd effect (2,177 animals from 96 farms; 21.4% seropositive animals and 43.1% positive farms based on total sample of 123 farms and 2,828 goats)