Orthoretrovirinae
Virus classification
(unranked):	Virus
Realm:	Riboviria
Kingdom:	Pararnavirae
Phylum:	Artverviricota
Class:	Revtraviricetes
Order:	Ortervirales
Family:	Retroviridae
Subfamily:	Orthoretrovirinae
Genera
Alpharetrovirus Betaretrovirus Deltaretrovirus Epsilonretrovirus Gammaretrovirus Lentivirus

Orthoretrovirinae is a subfamily of viruses belonging to Retroviridae, a family of enveloped viruses that replicate in a host cell through the process of reverse transcription.^[1] The subfamily currently includes six genera, of which Lentivirus contains the human immunodeficiency virus (HIV). These viruses cause a variety of tumors, malignancies and immune deficiency disease in humans, other mammals and birds. A few, like Simian immunodeficiency virus (SIV), apparently cause no disease in their natural hosts.^{[citation needed]}