Figure 3. Serum antibody responses in vaccinated chickens.

HI antibody titers against A) NDV Herts/33 or B) AIV measured in individual serum samples collected on day 21 p.v. via ON/IT or IM route. Titres are expressed as the reciprocal of the highest serum dilution showing HI. The dashed line indicates the lower limit of detection. Titers below the detection limit were assigned a value of 2 or 4, respectively for calculation of the mean. Horizontal bars represent the geometric mean titers of the groups and vertical bars represent 95% confidence intervals. Serum titers from chickens that died after the challenge are indicated by filled circles, the open circles correspond to animals that survived the challenge. For reference, each panel includes the same PBS group.