Group | Strain for challenge | Challenge dosea (CFU) | Temperature (°C) b
| Appetitec
| Lethargyc
| Dyspneac
| Lung lesion score d
|
|---|
1 | S-8△clpP△apxIIC
| 1.0 × 107
| 39.2 ± 0.3 | 0.2 ± 0.4*
| 0.1 ± 0.2**
| 0.2 ± 0.2**
| 1.8 ± 3.0**
|
2 | S-8 | 1.0 × 107
| 40.1 ± 0.4 | 1.8 ± 1.3 | 1.7 ± 0.7 | 1.9 ± 0.7 | 16.2 ± 8.5 |
3 | S-8△clpP△apxIIC
| 1.0 × 109
| 39.4 ± 0.5 | 0.4 ± 0.5*
| 0.3 ± 0.3**
| 0.4 ± 0.4**
| 3.0 ± 2.2**
|
4 | S-8 | 1.0 × 109
| 40.2 ± 0.6 | 2.4 ± 1.6 | 2.2 ± 0.6 | 2.5 ± 0.5 | 21.8 ± 5.8 |
5 | PBS | 0 | 39.4 ± 0.3 | 0 | 0 | 0 | 0 |
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a Groups of five pigs were given intranasal inoculations with 1 mL of bacterial suspension containing various quantities of A. pleuropneumoniae strains. Survival was recorded for 14 days after infection
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b The average temperature value for each piglet during the observation period was calculated and the mean temperature value for each group was determined
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c Clinical signs were scored as described by Jolie et al [24]. Appetite was scored as follows: 0, did eat; and 1, did not eat. The total score equaled the number of 12-h periods of not eating over the 36-h observation period. Lethargy was scored as follows: 0, normal; 1, slight inactivity; 2, moderate; and 3, severe. Dyspnea was scored as follows: 0, normal; 1, slight; 2, moderate; and 3, severe. The final scores were obtained from the average of all of the data within the observation time and are expressed as arithmetic means ± SD; *, significance at a P value of <0.05; **, significance at a P value of <0.01
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d The lung lesion score was determined as described by Hannan et al [25]
