TABLE 2.
S. enterica isolation rates and seroprevalence for pigs necropsied on the farm or at the abattoira
| Herd |
S. enterica isolation rate (%) (no. of samples tested) in:
|
% SPP (no. of samples tested)d
|
% Seroprevalence (mean juice ELISA OD% ≥ 40) (no. of samples tested)
|
|||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AFECb | NFEC
|
CC
|
LNNc
|
|||||||||||||
| Farm | Farm | Abattoir | Rate differencee | Farm | Abattoir | Rate differencee | Farm | Abattoir | Rate differencee | Farm | Abattoir | Rate differencee | Farm | Abattoir | Combined farm and abattoir | |
| 1 | 1.0 (97) | 0 (48) | 2 (50) | 2.0 | 0 (48) | 2 (50) | 2.00 | 6.3 (48) | 6.0 (50) | −0.30 | 6.3 (48) | 10 (50)fg | 3.80 | 0 (48) | 0 (45) | 0 (93)g |
| 2 | 1.1 (94) | 0 (44)f | 30 (50)f | 30.0 | 0 (44) | 4 (50) | 4.00 | 4.5 (44) | 6 (50) | 1.50 | 4.5 (44)f | 38 (50)fg | 33.50 | 77.3 (44) | 58 (50) | 67 (94)g |
| 3 | 0 (89) | 0 (45)f | 36.4 (44)f | 36.4 | 0 (45)f | 13.6 (44)f | 13.64 | 2.2 (45)f | 27.3 (44)f | 25.10 | 2.2 (45)f | 54.5 (44)fg | 52.30 | 0 (44) | 0 (42) | 0 (87)g |
| 4 | 4.4 (90) | 4.4 (45)f | 31.1 (45)f | 26.7 | 4.4 (45)f | 53.3 (45)f | 48.89 | 4.4 (45) | 0 (45) | −4.40 | 8.9 (45)f | 68.9 (45)fg | 60.00 | 13.3 (45) | 11.1 (45) | 12.2 (90)g |
| 5 | 2.0 (98) | 0 (49)f | 51.0 (49)f | 51.0 | 6.1 (49) | 10.2 (49) | 4.08 | 4.1 (49) | 10.2 (49) | 6.10 | 10.2 (49)f | 61.2 (49)fg | 51.00 | 25.0 (48) | 21.3 (47) | 23.5 (95)g |
| 6 | 0.0 (98) | 0 (50) | 2.1 (48) | 2.1 | 0 (50) | 2.1 (48) | 2.08 | 0 (50) | 6.3 (48) | 6.30 | 0 (50)f | 10.4 (48)f | 10.40 | 8.0 (50) | 6.3 (48) | 7.1 (98) |
| Mean (total) | 1.47 (566) | 0.7 (281) | 25.2 (286) | 24.5 | 1.8 (281) | 13.6 (286) | 11.9 | 3.6 (281) | 9.1 (286) | 5.53 | 5.3 (281) | 39.9 (286) | 34.52 | 20 (280) | 17 (286) | 18.55 (557) |
The 95% confidence limits for S. enterica isolation rates are as follows: AFEC, 0 to 2.3%; NFEC (farm), 0 to 1.7%; NFEC (abattoir), 20.1 to 30.2%; CC (farm), 0.2 to 3.3%; CC (abattoir), 9.7 to 17.6%; LNN (farm), 1.4 to 5.7%; LNN (abattoir), 5.8 to 12.4%. The 95% confidence limits for pig prevalence were 2.7 to 8.0% (farm) and 34.2 to 45.5% (abattoir). The 95% confidence limits for seroprevalence were 15.3 to 24.7% (farm), 12.5 to 21.4% (abattoir), and 15 to 22% (combined farm and abattoir).
1-g fecal samples taken 3 days before depopulation.
Results from the ICL and SIL nodes are combined.
SPP is defined as S. enterica isolation from any of the samples collected at necropsy (1 g of feces, CC, or lymph nodes).
Rate difference is the abattoir percentage minus the farm percentage.
Percentages are significantly different between farm and abattoir for that sample type and herd (P < 0.05).
Percentages are significantly different between pig prevalence (abattoir) and seroprevalence (combined farm and abattoir) for that herd (P < 0.05).