Retroviridae

(virology) A family of ribonucleic acid (RNA)-containing animal viruses characterized by spherical enveloped virions containing two single-stranded RNA molecules and reverse transcriptase, includes the subfamilies Oncovirinae, Spumavirinae, and Lentivirinae.

A family of viruses, many of which produce tumors, that contain RNA and reverse transcriptase, including the virus that causes AIDS.

A family of medium-sized (about 100 nm diameter) enveloped viruses with an icosahedral capsid enclosing the single-strand RNA genome which is diploid, i.e. two copies per virion. There are three subfamilies: Oncornavirinae, which includes avian, bovine, feline and murine leukemia/sarcoma viruses; Lentivirinae, which includes maedi/visna virus of sheep, caprine arthritis encephalitis and equine infectious anemia viruses and human immunodeficiency virus 1 and 2; Spumavirinae, which includes nonpathogenic viruses of monkey, cattle and cats, recognized only in cell culture where they produce syncytia (bovine and feline syncytia-forming viruses) which have a vacuolated cytoplasm, hence also called foamy viruses.