Retroviridae

noun plural

Ret·​ro·​vi·​ri·​dae ˌre-trō-ˈvir-ə-ˌdē 

: a family of single-stranded RNA viruses that replicate within a host cell via reverse transcription and incorporate into the genome of these cells as a provirus, that are often tumorigenic, and that include the foamy viruses, HIV, HTLV-I, Rous sarcoma virus, SIV, and the causative agents of avian leukosis, equine infectious anemia, ovine progressive pneumonia, and jaagsiekte see lentivirus