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Table 2 Univariate and multivariable analysis of average within herd prevalence (%) of pluck lesions and lung surface affected with pneumonia depending on farm serology for influenza A virus (IAV), porcine respiratory and reproductive syndrome virus (PRRSv) and Mycoplasma hyopneumoniae (Mhyo)a,b

From: A cross-sectional survey on respiratory disease in a cohort of Irish pig farms

  IAV PRRSv Mhyo
Dorsocaudal Pleurisy Pos: 9.8 (0.9, 51.8)
Neg: 2.4 (0.4, 47.7)
Pos: 10.2 (2.8, 51.8)
Neg: 4.0 (0.4, 49.5)
Pos: 8.2 (2.0, 51.8)
Neg: 2.9 (0.4, 47.7)
 Univariate P < 0.001 P = 0.008 P = 0.009
 Multivariable P < 0.001 - -
Mod Sev dorsocaudal pleurisy Pos: 7.5 (0.7, 46.9)
Neg: 1.7 (0.0, 42.6)
Pos: 8.7 (1.8, 46.9)
Neg: 3.8 (0.0, 42.6)
Pos: 6.8 (0.5, 46.9)
Neg: 2.6 (0.0, 42.6)
 Univariate P < 0.001 P = 0.006 P = 0.025
 Multivariable P < 0.001 - -
Cranial pleurisy Pos: 12.4 (1.9, 54.2)
Neg: 4.8 (1.2, 35.1)
Pos: 12.4 (4.2, 54.2)
Neg: 7.1 (1.2, 51.6)
Pos: 10.9 (2.5, 54.2)
Neg: 5.8 (1.2, 35.1)
 Univariate P = 0.001 P = 0.007 P = 0.032
 Multivariable P < 0.001 - -
Pneumonia Pos: 9.5 (0.7, 50.0)
Neg: 1.5 (0.0, 18.9)
Pos: 10.3 (1.3, 34.7)
Neg: 2.6 (0.0, 50.0)
Pos: 11.0 (2.0, 50.0)
Neg: 1.3 (0.0, 30.7)
 Univariate P = 0.003 P = 0.035 P < 0.001
 Multivariable P = 0.023 - P < 0.001
Avg pneumonia surface c Pos: 6.0 (1.0, 13.5)
Neg: 2.7 (0.0, 9.5)
Pos: 6.4 (2.2, 13.5)
Neg: 4.6 (0.0, 10.6)
Pos: 6.5 (2.0, 13.5)
Neg: 2.3 (0.0, 6.6)
 Univariate P = 0.002 P = 0.014 P < 0.001
 Multivariable - - P < 0.001
Scars Pos: 12.5 (1.9, 39.3)
Neg: 2.3 (0.0, 23.1)
Pos: 17.5 (1.4, 39.3)
Neg: 8.0 (0.0, 24.3)
Pos: 15.9 (3.1, 39.3)
Neg: 2.5 (0.0, 13.2)
 Univariate P < 0.001 P < 0.001 P < 0.001
 Multivariable P = 0.008 - P < 0.001
Abscesses Pos: 0.5 (0.0, 11.1)
Neg: 0.1 (0.0, 21.5)
Pos: 0.3 (0.0, 4.3)
Neg: 0.3 (0.0, 21.5)
Pos: 0.5 (0.0, 11.1)
Neg: 0.2 (0.0, 21.5)
 Univariate P = 0.073 P = 0.842 P = 0.194
 Multivariable P = 0.061 - -
Pericarditis Pos: 8.0 (1.2, 19.1)
Neg: 6.1 (1.5, 14.8)
Pos: 8.0 (2.3, 16.4)
Neg: 7.4 (1.2, 19.1)
Pos.: 8.2 (1.5, 19.1)
Neg.: 5.5 (1.2, 15.6)
 Univariate P = 0.251 P = 0.561 P = 0.018
 Multivariable - - P = 0.024
Liver milk spots Pos: 27.1 (0.5, 97.3)
Neg: 12.4 (0.4, 88.8)
Pos: 24.4 (0.5, 87.9)
Neg: 17.8 (0.4, 97.3)
Pos.: 15.7 (0.4, 88.8)
Neg.: 25.3 (0.4, 97.3)
 Univariate P = 0.374 P = 0.838 P = 0.899
 Multivariable - - -
  1. aUnivariate analysis was carried using Mann-Whitney test and data is presented as median (range) for positive (pos) and negative (neg) farms. Multivariable analysis was carried out using generalized linear models with forward selection with a P for inclusion of 0.10 and a P for retention of 0.05
  2. bResults for APP are not presented as there was only one farm negative to it
  3. cAverage lung surface affected with pneumonia (%)