Characteristics No of samples No. (%) H3 positive Adjusted OR 95% confidence intervals p-value
Length of stay at slaughterhouse Length of stay at slaughterhouse Length of stay at slaughterhouse Length of stay at slaughterhouse Length of stay at slaughterhouse Length of stay at slaughterhouse
< 1 day 3446 33 (1.0) 1 Reference
1-2 days 2183 23 (1.1) 1.30 0.76-2.25 0.339
>2 days 203 2 (1.0) 1.20 0.28-5.08 0.802
Transport distance† Transport distance† Transport distance† Transport distance† Transport distance† Transport distance†
Nearest 3863 45 (1.2) 1 Reference
More distant 1519 12 (0.8) 0.77 0.39-1.15 0.449
Most distant 450 1 (0.2) 0.18 0.02-1.34 0.094
Anti-H3 HAI titer Anti-H3 HAI titer Anti-H3 HAI titer Anti-H3 HAI titer Anti-H3 HAI titer Anti-H3 HAI titer
Sero-negative (<1:40) 4625 52 (1.1) 1 Reference
Sero-positive (≥1:40) 1207 6 (0.5) 0.33 0.14-0.79 0.012
Sero-prevalence of source farms Sero-prevalence of source farms Sero-prevalence of source farms Sero-prevalence of source farms Sero-prevalence of source farms Sero-prevalence of source farms
Low (<10%) 1963 16 (0.8) 1 Reference
Moderate (10-30%)
2047
16 (0.8)
1.16
0.57-2.34
0.682
High (>30%) 1822 26 (1.4) 2.25 1.17-4.32 0.150
Total 5832 58 (1.0)