Table 2.
Group | Condition/Immunization | Virus Titersa
|
|||||
---|---|---|---|---|---|---|---|
3 dpcb | 5 dpc | 7 dpc | 9 dpc | 11 dpc | 13 dpc | ||
1 | Naïve | 5.8 ± 1.7 (9/9) | 6.4 ± 0.6 (9/9) | 4.4 ± 1.4 (8/9) | 2.0 ± 1.0 (8/9) | 1.3 ± 0.7 (2/9) | < c |
2 | Vaccine Control | 2.5 ± 4.2 (2/9) | 4.4 ± 2.5 (4/9) | 5.4 ± 1.3 (3/9) | 6.5 ± 1.4 (2/9) | < | < |
3 | Lab Antiserum, Neat | 2.5 ± 0.0 (1/10) | 3.5 ± 0.0 (1/10) | 0.8 ± 0.0 (1/10) | < | < | < |
4 | Lab Antiserum, 1:2 dilution | 3.9 ± 0.9 (2/11) | 4.9 ± 0.5 (2/11) | 6.8 ± 0.4 (2/11) | 4.0 ± 1.8 (4/11) | 5.8 ± 1.2 (3/11) | 6.9 ± 0.5 (2/11) |
5 | Lab Antiserum, 1:2 dilution | 6.1 ± 0.7 (3/11) | 6.0 ± 0.9 (6/11) | 4.1 ± 2.3 (6/11) | 3.8 ± 2.5 (4/11) | 0.8 ± 0.0 (1/11) | < |
6 | Field Antiserum, Neat | 6.3 ± 1.8 (8/10) | 6.5 ± 0.4 (10/10) | 4.3 ± 1.6 (10/10) | 3.8 ± 0.6 (5/10) | 2.3 ± 0.0 (1/10) | < |
7 | Field Antiserum, 1:2 dilution | 4.2 ± 1.9 (4/10) | 6.7 ± 1.0 (10/10) | 6.2 ± 0.4 (10/10) | 4.1 ± 2.5 (9/10) | 1.0 ± 0.4 (3/10) | < |
8 | Field Antiserum, 1:2 dilution | 5.5 ± 0.0 (1/11) | 5.8 ± 2.4 (6/11) | 6.0 ± 0.9 (4/11) | 5.4 ± 1.4 (4/11) | 4.3 ± 2.9 (6/11) | 7.0 ± 0.8 (6/11) |
Expressed as the arithmetic mean (± sd), log10 EID50/ml from 5 positive samples. Values below the limit of detection (0.75 log10EID50/ml) were excluded from calculations. Values in parenthesis are the number of birds shedding/total. For timepoints having fewer than 5 birds shedding, all positive samples were used to determine mean titer.
days post-challenge
< indicates all chickens at this time point had titers below the cutoff value.