Siv

SIV, or Simian Immunodeficiency Virus, is a lentivirus that infects non-human primates such as macaques, sooty mangabeys, and chimpanzees. It belongs to the family Retroviridae and is genetically diverse across primate species. In natural hosts, SIV infections are often nonpathogenic or cause only mild disease.

The virus has an enveloped, single-stranded RNA genome about 9.7 kilobases in length. As with other lentiviruses, its genome encodes structural genes gag, pol, and env, along with regulatory and accessory genes such as tat, rev, vif, vpr, and nef. SIV replicates via reverse transcription and integrates into the host genome.

In some natural hosts, SIV establishes a long-term, largely asymptomatic infection, with controlled immune activation. In other non-natural hosts or experimental settings, SIV infection can cause AIDS-like disease, making it a valuable model for studying lentiviral pathogenesis.

Evolutionarily, SIV is the closest relative of HIV. Several transmission events from primates to humans have given rise to HIV-1 and HIV-2. HIV-1 Group M is derived mainly from SIVcpz in chimpanzees, while HIV-2 traces to SIVsm in sooty mangabeys. Many SIV strains remain restricted to their natural hosts.

Transmission among primates occurs through exposure to infected bodily fluids, blood contact, and from mother to offspring. Zoonotic transmission to humans is rare but has occurred, particularly in settings with close contact with infected animals or tissues. SIV studies in non-human primates provide insights into HIV biology and immune control.

Usage in research: SIV-infected macaques and other models are used to study disease progression, vaccines, and potential cures for HIV/AIDS, as well as to understand host–virus interactions and immune responses.

Notes: This article focuses on Simian Immunodeficiency Virus. SIV can refer to other terms in different contexts.