The HIV virus is a type of retrovirus. This means that it has to make a DNA copy of its genetic material (RNA) in order to replicate. The virus also belongs to a group of viruses called lentiviruses. Infection with a lentivirus, such as HIV, is characterized by a long interval between infection and the onset of symptoms.
The HIV virus belongs to a class of viruses called retroviruses. Retroviruses are RNA (ribonucleic acid) viruses, and in order to replicate (duplicate), they must make a DNA (deoxyribonucleic acid) copy of their RNA. It is the DNA genes that allow the virus to replicate.
Like all viruses, the HIV virus can only replicate inside cells, taking over the cell's machinery to reproduce. Different from other viruses, once inside the cell, the HIV virus and other retroviruses use an enzyme called reverse transcriptase to convert their RNA into DNA. The DNA can then be incorporated into the host cell's genes.
The HIV virus belongs to a subgroup of retroviruses known as lentiviruses, or "slow" viruses. The course of infection with these viruses is characterized by a long interval between initial infection and the onset of serious symptoms.
Other lentiviruses infect nonhuman species. For example, the feline immunodeficiency virus (FIV) infects cats, and the simian immunodeficiency virus (SIV) infects monkeys and other nonhuman primates. Like the HIV virus in humans, these animal viruses primarily infect immune system cells, often causing immune deficiency and AIDS-like symptoms. These viruses and their hosts have provided researchers with useful, albeit imperfect, models of the HIV disease process in people.