ABSTRACT
This chapter reviews some of the documented examples of interaction between two animal viruses, ranging from closely related to widely divergent groups. Herpes- and retroviruses have been shown to exhibit some similarities in morphology; each possesses an outer envelope that surrounds their nucleocapsids, but the herpesviruses are significantly larger than the retroviruses. Several herpesviruses have been associated with lymphomas and leukemias in man and animal species. The possible role that herpesviruses play through their pseudotype variants in the etiology of cancer may become apparent. Mixed infections with herpes- and retroviruses have been studied by several investigators under both natural and experimental conditions. Most retroviruses contain an RNA-directed DNA polymerase and possibly an interspecies group-specific antigen. Interaction between two animal viruses appeared to be a fairly frequent event that could be repeatedly demonstrated, whether between related or unrelated DNA or RNA viruses.
