What Is HIV/AIDS and How It Affects the Body

What Is HIV/AIDS and How It Affects the Body

Human Immunodeficiency Virus (HIV)

Human Immunodeficiency Virus (HIV) is a lentivirus, a subgroup of retrovirus, that causes HIV infection and leads over time to acquired immunodeficiency syndrome (AIDS), a condition in humans where progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive. Without treatment, the average survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype.

How HIV Affects the Body

HIV primarily targets the immune system, which consists of white blood cells, notably CD4+ T cells, macrophages, and dendritic cells. The virus enters host cells using a protein on its surface called gp120, which binds to the CD4 receptor on the surface of immune cells. After binding, the virus fuses with the cell membrane and releases its RNA into the host cell. Once inside, the viral RNA is reverse-transcribed into DNA and integrates into the host cell's genome, where it can remain dormant or begin actively replicating.

The progressive destruction of CD4+ T cells severely impairs the immune system's ability to fight off infections and disease. As the number of these immune cells declines, individuals become susceptible to opportunistic infections, which are infections that occur more frequently and are more severe in individuals with weakened immune systems.

AIDS: The Consequence of HIV Infection

Acquired Immunodeficiency Syndrome (AIDS) is the advanced stage of HIV infection and is defined by a CD4+ T cell count below 200 cells per cubic millimeter of blood or the occurrence of specific diseases associated with immune system compromise. Normally, a healthy adult's CD4+ T cell count ranges from approximately 500 to 1,200 cells per cubic millimeter.

When the immune system is critically compromised, various opportunistic infections, such as tuberculosis, pneumonia, and Kaposi's sarcoma, become more common and severe. Neurological complications, weight loss, chronic diarrhea, and more, can also manifest at this stage, significantly affecting the quality of life and leading to increased mortality.

Diagnosis and Management

HIV infection is diagnosed through blood tests that detect HIV antibodies, antigens, or nucleic acids. Early diagnosis and treatment are crucial, as the initiation of antiretroviral therapy (ART) soon after diagnosis helps to control viral replication, maintain immune function, and prevent progression to AIDS.

ART involves a combination of HIV medicines (called an HIV treatment regimen) taken every day. ART reduces the amount of virus in the blood (viral load) to an undetectable level, meaning the virus is suppressed to fewer than 20-50 copies/mL on standard laboratory tests. An undetectable viral load means the virus cannot be transmitted sexually, a concept known as "U=U" (Undetectable = Untransmittable).

Conclusion

HIV is a chronic condition that dramatically impacts the immune system, making the body vulnerable to a wide array of infections and diseases. Advances in medicine, particularly the development of ART, have transformed HIV from a fatal diagnosis to a manageable chronic illness. With proper treatment, individuals with HIV can enjoy a life expectancy comparable to that of the general population and can significantly reduce the risk of transmission. Public health efforts continue to focus on prevention, early diagnosis, and universal access to treatment to combat this global epidemic.