Both DetectiV and E-Predict [9] have been used to analyze the data. For DetectiV, the data were not corrected for local background. Missing, negative and zero values were set to a nominal value of 0.5. Intensities were averaged across replicate probes. Median normalization was then carried out, followed by a t-test grouping the data by virus species. Probes representing actin, GAPDH and Line_Sine were filtered from Table 1 DetectiV normalization methods