3. Results
3.1. Clinical observations and fecal consistency scores in PEDV-
inoculated nursing piglets vs. weaned pigs
Clinical signs were
first detected at PID 1 in PEDV-inoculated
nursing piglets. All inoculated nursing piglets at PIDs 1–5 exhibited
acute, severe watery diarrhea (all scores, 3) and/or vomiting,
followed by lethargy and dehydration. However, no inoculated
nursing piglets were found dead or were euthanized (moribund)
due to severe clinical disease at PIDs 1–5. On the other hand, no
clinical signs were detected until PID 3 in PEDV-inoculated weaned
piglets. At PID 3, 3 of 8 inoculated weaned pigs exhibited mild
diarrhea (all scores of 2) and/or vomiting. At PID 5, fecal samples
from 4 inoculated weaned pigs appeared normal (scores, 1 or 1.5).
No negative control nursing and weaned pigs showed diarrhea
or other clinical signs throughout the experiment. At PIDs 1–5,
fecal consistency scores in PEDV-inoculated nursing pigs were
significantly higher than those in PEDV-inoculated weaned pigs
(P < 0.01 at each-time point) (Fig. 1).