Viral genome enrichment:
The cell culture supernatant was harvested after three freeze-thaw cycles and centrifuged at 4000 RPM for 10 min. The clarified culture supernatants harvested at third passage were tested by real time PCR (Fernández-Pinero et al., 2013) and used for further process. The viral genome enrichment was carried out as described earlier, with minor modifications (Chapman et al., 2011). Briefly, cell supernatant containing virus was centrifuged at 118000 xg for 1h at 4°C. The pellet resuspended in equilibrating buffer (NaCl 10mM, Tris-HCl 10mM, EDTA 1mM) was treated with 75 units of DNase I for 1h at 37°C. The virus was pelleted over 20% sucrose in equilibrating buffer at 62000xg for 1.5 h. The pellet was treated with RNAse (40 µg/mL), proteinase K (200 µg/mL), and 1% sodium dodecyl sulfateand incubated for 18 h at 37°C. The genomic DNA was extracted from the enriched pellet by phenol-chloroform method (Sambrook and Russell, 2006).