What type of virus is HIV?

HIV, or Human Immunodeficiency Virus, is classified as a retrovirus. This classification is primarily due to its replication mechanism that involves reverse transcription. Retroviruses possess an RNA genome that is reverse transcribed into DNA by the viral enzyme reverse transcriptase once the virus enters a host cell. This DNA is then integrated into the host cell's genome, allowing for the production of viral particles through the host's cellular machinery.

The retrovirus classification is significant because it implies distinctive characteristics in terms of pathogenesis and viral behavior. HIV specifically targets CD4+ T cells, crucial components of the immune system, which leads to the progressive immunosuppression characteristic of AIDS (Acquired Immunodeficiency Syndrome). Understanding that HIV is a retrovirus helps inform treatment strategies, such as the use of antiretroviral therapy, which aims to inhibit this replication process.

In contrast, while HIV is indeed an RNA virus and can be associated with oncogenesis under certain conditions, its defining characteristic relates to its retroviral nature, which focuses on reverse transcription and integration of its viral genome into the host DNA. Other viruses listed do not have these same replication characteristics or classifications, defining the unique nature of HIV as a retrovirus.