TABLE 3.
Onset of diarrhea and fecal virus shedding and histopathologic findings in the small intestines of Gn calves after inoculation with BEC-NB strain
| Inoculation route | Calf no. | Age exposed (days) | Age euthanized (days) | Onset of diarrhea (PID) | Onset of fecal virus shedding (PID)
|
Intestinal lesion scorea
|
|||
|---|---|---|---|---|---|---|---|---|---|
| IEM | RT-PCRb | Duodenum | Jejunum | Ileum | |||||
| Oral | 1 | 4 | 8 | 4 | 2 | 1 | 2.5 | 1.5 | 1.0 |
| Oral | 2 | 5 | 10 | 4 | 2 | 2 | 2.5 | 2.0 | 0 |
| i.v. | 3 | 3 | 7 | 3 | 2 | 2 | 3.0 | 1.5 | 0 |
| i.v. | 4 | 7 | 11 | 3 | 2 | 2 | 1.0 | 2.5 | 0 |
| Mock | 5 | 4 | 6 | NDc | ND | 0 | 0 | 0 | |
a
0, normal; 1, mild villous atrophy; 2, moderate villous atrophy; 3, severe villous atrophy.
b
All calves (except no. 2 [specimens discarded]) were tested for BEC by RT-PCR preexposure (PID 0) and were negative.
c
ND, not determined; specimens discarded (freezer failure); other mock-inoculated Gn calves (age matched) tested negative for BEC in feces by IEM and RT-PCR.