Fig. 3.

Dose titration of QR448(a) in SPF chickens challenged with 1 × 10⁴ EID₅₀ of the pathogenic Mass41 strain of IBV per bird. Solid line = treatment 2 h before challenge and dashed line = treatment 2 h after challenge. Detection of viral RNA in tracheal swab samples by real-time RT-PCR is presented as the average cycle threshold value (higher numbers equal less virus) for each group (n = 10). Dilutions of QR448(a) represent no dilution (0), or doubling dilutions beginning with a 1:5 dilution. No treatment are non-treated and challenged birds.