A concise explanation of HIV/AIDS
HIV (Human Immunodeficiency Virus) is a retrovirus that can be transmitted between people by unsafe sexual contact, if at least one person is infected with HIV. In infected humans, the HIV-virus enters cells that express the cell surface protein CD4 and co-receptors CCR5 and/or CXCR4. When this virus enters the cell, it converts the genetic information of HIV (or RNA) into DNA with reverse transcriptase. The DNA is then incorporated in the host cell’s chromosome and can subsequently be replicated and used to make viral proteins (see figure below). When there are enough copies of the virus, the host cell bursts open releasing the viruses to find new host cells and the host cell dies.
The most common victim of HIV is the CD4 T cell and the number of these cells decline during HIV infection. Because CD4 T cells are essential for the functioning of the immune system, this decline is the main reason for the weakened immune system of the HIV-patients. As a consequence, late-stage HIV-patients are susceptible to infections that are harmless in healthy humans. The most advanced stages of HIV-infection are generally known as AIDS (Acquired Immunodeficiency Syndrome).
The first symptoms occur shortly after the HIV-infection. Patients usually display symptoms like a sore throat, fever and a blotchy red rash. These early symptoms last up to three weeks and are commonly diagnosed as flu or a mild viral infection. After that, the HIV-infection can stay without symptoms for many years before the patient’s immune system will start to get significantly weaker. Common symptoms of a more advanced HIV-infection and AIDS are swollen lymph nodes, recurring herpes and weight loss.
Prevention and treatment
To prevent HIV infection from entering the AIDS stage, quick diagnosis and adequate treatment is needed. New diagnostic tools are able to detect HIV a month after infection, even before the patient expresses HIV-specific symptoms. If an infection is picked up on early, the doctor will regularly check the CD4 T cell count in the blood. One of the common treatments is the so-called antiretroviral therapy (ART). This therapy prevents common symptoms of HIV by slowing down the replication of the HIV virus.