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HIV stands for the human immunodeficiency virus. Having HIV can lead to having AIDS, but HIV is not the same as AIDS.
A virus is an infectious particle that is so small it can’t be seen even through a basic microscope. No virus is able to reproduce on its own. It can only multiply by infecting and taking over a host cell.
When a virus encounters a cell that can function as a host, it injects its own genetic material into the host cell. This causes the infected cell to produce more viral protein and genetic material instead of producing its own genetic code.
There are two types of HIV known as HIV-1 and HIV-2. In the United States, HIV typically refers to HIV-1 unless otherwise noted.
The HIV virus acts by infecting and killing cells in the human immune system known as CD4+T cells. CD4+ cells are one type of white blood cell that act as the body’s main infection fighting cells.
Without these cells, the immune system loses its ability to protect the body from infections, which makes it more likely that a person with HIV can get sick.
When the HIV virus takes over a CD4+ cell, that cell stops working as part of the immune system and is not able to reproduce to create any more CD4+ cells. Instead, the CD4+ cell reproduces the genetic material from the virus and sends it back out in to the body to infect more host cells.
This allows the virus to multiply and eventually damage enough CD4+ cells that the immune system is not able to do its job, leaving the body at higher risk for infections.
HIV starts damaging the immune system as soon as it enters the body. Some people may have symptoms similar to the flu within a few weeks of being infected with HIV.
These symptoms can last one to two weeks before going away. Other people do not have any symptoms shortly after becoming infected.
It is possible for someone with HIV to look and feel healthy for several years. But the damage to the immune system is on-going during this time.
Whether or not symptoms are present, any person infected with HIV should get regular health checkups.