Viral titers in tissues of H9N2-infected chickens. Chickens (n = 5 per group) were i.n. infected with A/Chicken/Korea/S21/2004 (H9N2) and tissues of trachea, lung, and intestine were collected on 1, 2 or 4 days pi. Tissues of infected or uninfected chickens were homogenized in 1 mL of PBS and the viral titers were determined by log10EID50/mL. Data represent the mean ± standard errors of the viral titers of five chickens. Statistical analysis was performed by the comparison of data of uninfected chickens. No virus was detected in uninfected chickens. [*P < 0.05], [**P < 0.001].