Differential STAT-3 regulation between H5N1 virus-infected chickens and ducks. In the lungs and spleens of 3-weeks-old chickens at 24 h following infection with H5N1-tyTR05 viruses, (A) expression of STAT-3 was significantly down-regulated whereas (B) IFN-α was significantly up-regulated. In the lung and spleen tissues from 4- weeks- old ducks at 24 h following infection with H5N1-tyTR05 virus, (C) STAT-3 expression was unaffected and (D) IFN-α expression was significantly up-regulated. Relative mRNA expression was determined by real-time PCR normalised to 18S rRNA. Data points are the mean of three biological replicates with error bars as standard deviation (*p < 0.05).