TABLE 3.
Survival of piglets orally challenged with 1010 CFU of STEC 86-24 followed by intramuscular administration of either a placebo or an Stx2-neutralizing VNA treatment 24 h or 48 h later
| Treatment (h post-STEC challenge) | Dose (vp/kg) | No. of piglets | No. of surviving piglets (% survival)a | Mean time (days) to death/euthanasia (± SD)b | Mean serum VNA concn (μg/ml) (range)c |
|---|---|---|---|---|---|
| Placebod (24) | 1 × 1011 or 1 × 1012 | 6 | 0 (0) | 3.50 (±0.54) A | Not relevante |
| Ad/VNA-Stx (24) | 1 × 1012 | 4 | 3 (75) | 5.0 BC | 0.70 (0.2–2.0) |
| 1 × 1011 | 6 | 6 (100) | 9.0 (±0.0) BC | 0.08 (0.03–1.0) | |
| Ad/VNA-Stx (48) | 1 × 1012 | 7 | 4 (57) | 3.33 (±0.57) AC | 0.23 (0.05–0.4) |
| 1 × 1011 | 2 | 1 (50) | 3.0 AC | 0.15 |
Piglets that did not survive either died overnight or were euthanized due to severe illness.
Surviving piglets in the Ad/VNA-Stx groups were euthanized after 9 days. The survival times of piglets that either were euthanized or died in Ad/VNA-Stx groups are shown. Survival times followed by the same capital letter are not statistically significantly different. Different capital letters following survival times indicate statistically significant differences (P < 0.05).
Estimated concentration of VNA in piglet serum at the time of euthanasia.
Four piglets in the placebo group received 1012 vp of Ad/VNA-BoNTA/kg, and two received 1011 vp of Ad/VNA-Tcd/kg.
The estimated mean VNA concentration in the sera of pigs receiving 1012 vp of Ad/VNA-BoNTA/kg was 3.75 μg/ml, and that for pigs receiving 1011 vp of Ad/VNA-Tcd/kg was 0.02 μg/ml.