Respiratory syncytial virus (RSV) NS1 and NS2 genes expressions across the experimental groups. Six groups of BALB/c mice were intranasally treated with 32 μl of normal saline (uninfected), RSV A2 (RSV(R)), Pr/H3N2 (IAV (I)) or co-treated simultaneously (I + R) or one after the other at 24 hours interval (IR and RI). On days 2, 4 and 7, mRNA was extracted from lungs (n = 5) for real time PCR analysis of RSV genes. (A) mRNA expression level of NS1 gene (B) mRNA expression level of NS2. RSV NS1 and NS2 expressions were downregulated by day 7 in I + R group. CT values were normalized with GADPH, mRNA expression level was calculated using 2−ΔΔCT method and presented as Log10 fold increase relative to uninfected controls. mRNA expressions for RSV NS1 and NS2 were not detected in IAV (single virus) infected mice. * vs Day 2 and # vs Day 4 for within group comparison while a vs RI, b vs IR and c vs I + R for comparing between groups of the same day (p < 0.05). @ No data was available for I + R and RSV (R) on day 2.