Large numbers of virus species exist in the realm of nature, and are now classified into distinct sub-groups based on their biochemical and biological characteristics (Knipe et al., 2007). Viruses are unique in their genomic composition, nucleocapsid/ virion morphology, replication strategy, and/or target host. Even though viruses represent the smallest entity encoding a genetic program and are strictly dependent on hosts for their replication, they adapt themselves in a species-specific and dexterous manner to infect or persist in a wide variety of living things. In the course of interaction with hosts, viruses somehow find ecologica
