Table 3 Univariable logistic regression of farm-based factors associated with serological Q fever infection on animal level

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