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Table 2 Differences in farm characteristics between IAV-S-positive and IAV-S-negative farms

From: Effect of herd size on subclinical infection of swine in Vietnam with influenza A viruses

Variable

 

IAV-S-positive farms,

IAV-S-negative farms,

Odds ratio

95 % CI

p valuea

no.

(%)

no.

(%)

   

Farm typeb

Family-operated farm

6

(27.3 %)

183

(86.3 %)

 

reference

 

Corporate farm

16

(72.7 %)

29

(13.7 %)

16.83

6.09 to 46.52

<0.001

Total number of pigs

<50

4

(18.2 %)

108

(47.8 %)

 

reference

 

50 to 500

1

(4.5 %)

83

(36.7 %)

0.33

0.04 to 2.97

0.319

501 to 1000

1

(4.5 %)

14

(6.2 %)

1.93

0.20 to 18.50

0.569

≧1000

16

(72.7 %)

21

(9.3 %)

20.57

6.25 to 67.70

<0.001

Shower-in facility for humansc

No

5

(26.3 %)

195

(85.9 %)

17.06

reference

 

Yes

14

(73.7 %)

32

(14.1 %)

 

5.75 to 50.62

<0.001

Disinfection facility for vehiclesc

No

7

(31.8 %)

194

(85.8 %)

12.99

reference

 

Yes

15

(68.2 %)

32

(14.2 %)

 

4.92 to 34.34

<0.001

Other animals on farmd

No

9

(42.9 %)

33

(16.1 %)

0.26

reference

 

Yes

12

(57.1 %)

172

(83.9 %)

 

0.10 to 0.66

0.005

Type of operation

Not farrow-to-finishe

5

(22.7 %)

91

(39.9 %)

 

reference

 

Including farrow-to-finish

17

(77.3 %)

137

(60.1 %)

2.26

0.81 to 6.34

0.12

Type of pig housef

Open- or semi-open-sided house

20

(90.9 %)

178

(78.1 %)

0.36

reference

 

Windowless

2

(9.1 %)

50

(21.9 %)

 

0.08 to 1.58

0.173

Introduction of pigs

No

1

(5.6 %)

30

(19.7 %)

4.18

reference

 

Yes

17

(94.4 %)

122

(80.3 %)

 

0.54 to 32.67

0.173

Vaccinationg

No

1

(5.3 %)

32

(15.1 %)

3.20

reference

 

Yes

18

(94.7 %)

180

(84.9 %)

 

0.41 to 24.82

0.266

Respiratory diseases history in pigh

No

15

(68.2 %)

208

(91.2 %)

 

reference

 

Yes

7

(31.8 %)

20

(8.8 %)

4.85

1.77 to 13.29

0.002

Respiratory diseases history in working staffh

No

20

(90.9 %)

225

(98.7 %)

 

reference

 

Yes

2

(9.1 %)

3

(1.3 %)

7.50

1.18 to 47.54

0.032

Livestock farm

No

14

(68.2 %)

116

(91.2 %)

 

reference

 

within 100 mi

Yes

6

(31.8 %)

111

(8.8 %)

0.45

0.17 to 1.21

0.112

Pig farm within 100 m

No

14

(68.2 %)

157

(91.2 %)

0.96

reference

 

Yes

6

(31.8 %)

70

(8.8 %)

 

0.35 to 2.61

0.938

  1. aLogistic regression analyses were performed to calculate odds ratio of IAV-S-positive vs -negative farms for each variable
  2. bCorporate farm managed by a company, and family-operated farm managed by owner’s family
  3. cDisinfection facilities for humans or vehicles at the farm entrance
  4. dPoultry (chickens, ducks), dogs, cats, cattle, etc
  5. eFarrow-to-wean or wean-to-finish farms
  6. fWindowless house or (semi-) open-sided house
  7. gVaccines for diseases other than swine influenza. Swine influenza vaccine is not available in Vietnam
  8. hRespiratory symptoms observed in pigs or working staff within the 6 months before our sampling
  9. iPresence of livestock farms including pig farm within 100 m
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BMC Veterinary Research

ISSN: 1746-6148

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