Humanized animal viruses with special reference to the primate adaptation of morbillivirus.

This review article discusses the evolution of human viruses with special reference to paramyxoviruses. This family of viruses causes epidemics representing the dissemination of infection from one acutely infected host to the next. Since there is no repository for human paramyxoviruses in animals or in the form of persistent infections in man, the history of epidemics afflicting human civilization is short, presumably not exceeding 4000-5000 years. Evolutionary relationships can be deduced for comparison of nucleotide sequences of genes or even complete genomes. The present paramyxovirus genus will probably in the future be divided into two separate genera. In the genus morbillivirus, two pairs of more closely related virus types can be distinguished: canine and phocid viruses, and rinder-pest and measles viruses, respectively. It is speculated that recombination events may have occurred in the evolution of the morbillivirus archetype.