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Introduction
HIV stands for the human immunodeficiency virus, which is the virus that causes AIDS. HIV is different from most other viruses because it attacks the immune system. There are two types of HIV virus – type 1 is found all around the world, while type 2 is found primarily in West Africa. The illness caused by these different virus strains can be different. For example the onset of illness in a person infected by HIV-2 is usually slower and less severe than if the person were infected by HIV-1. Once a person becomes infected by the HIV virus, the infection cannot be cured, but can often be managed by a range of anti-HIV medications, which inhibit the virus’s ability to replicate inside the body. HIV causes illness by damaging the immune system. HIV targets and destroys a special type of immune cell called T cells, which are part of the white blood cell family. These cells are an integral part of the immune system because they lead the fight against infections. When T cells become infected by the HIV virus they become severely damaged and usually die. This damages the person’s ability to fight infections and they often get sick for diseases that do not affect people with healthy immune systems. Over time, a person who is infected with HIV will experience a drop in white blood cell numbers until their immune system becomes completely overwhelmed or exhausted. At this point T cell numbers drop below a certain threshold and the illness is then referred to as AIDS. Having AIDS means that the virus has weakened the immune system to the point at which the body has a very difficult time fighting infections. The time in takes for HIV to progress to AIDS is extremely variable and can range for several years to many decades. The virus is primarily found in the blood, semen and vaginal fluid of an infected person and HIV is referred to as a sexually transmitted disease because the most common way of getting it is through unprotected sexual contact with an infected person. Because HIV is found in the blood, it can also spread between people who share needles or syringes. The virus is also able to cross the placental barrier; therefore women who are HIV positive can transmit the disease to their children. This can occur before or during birth. HIV can also be transmitted through breastfeeding.
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