The statistical analysis of the in vitro and in vivo infectivity experiments was performed using the GraphPad Prism software (version 5.0 for Windows). The differences were evaluated by oneway ANOVA analysis, followed by the Bonferroni' test. Differences were considered significant when P,0.05. Statistical analyses evaluating the intensity and variation of the protein expression profile in the 2-DE gels and immunoblotting were also performed, as described above. The **data** are representative of three independent experiments, performed in triplicate, which presented similar results.