Total numbers of A heterophils, B monocytes and C lymphocytes in blood. Chickens were uninfected or experimentally infected with ER on day 0, “naïve” and “vaccinated” groups. Blood samples were collected at the indicated days. Results are shown as group mean values ± 95% CI where non-overlapping CI indicate statistically significant differences. On days −3 and 15 n = 13/group, on days 1, 5 and 8 n = 7/group and on days 3 and 11 n = 6/group. For details see "Materials and methods" section.