Promiscuous viruses-how do viruses survive multiple unrelated hosts?

Arthropod-borne viruses (arboviruses) require efficient replication in taxonomically divergent hosts in order to perpetuate in nature. This review discusses recent advances in our understanding of the phylogenetic position of arthropod-borne viruses relative to insect-specific viruses, which appear to be more common and ecological requirements for successful adoption of the 'arbovirus phenotype.' Several molecular and other mechanisms that permit replication in divergent hosts are also discussed.