How does HIV affect the immune system, and what are the primary methods of transmission?

SouravNovember 8, 2024

Answered step-by-step

HIV (Human Immunodeficiency Virus) significantly impacts the immune system and is transmitted through specific behaviors and body fluids. Understanding these aspects is crucial for prevention and management.

Effects of HIV on the Immune System

1. Targeting CD4 Cells:
   • HIV primarily attacks CD4 T cells, a type of white blood cell that plays a vital role in the immune response. The virus enters these cells, replicates, and ultimately destroys them, leading to a progressive decline in their numbers.
2. Immune System Weakening:
   • As the CD4 cell count drops, the immune system becomes increasingly compromised. This makes the body less capable of fighting off infections and diseases, including those that are typically mild in healthy individuals. When the CD4 count falls below 200 cells/mm³, a person is diagnosed with AIDS (Acquired Immunodeficiency Syndrome), marking a severe stage of HIV infection.
3. Opportunistic Infections:
   • Individuals with HIV are more susceptible to opportunistic infections—illnesses that occur more frequently and are more severe in individuals with weakened immune systems. Common opportunistic infections include tuberculosis (TB), pneumonia, and certain cancers.
4. Chronic Immune Activation:
   • Chronic HIV infection leads to ongoing immune activation, which can further deplete CD4 cells and cause inflammation throughout the body. This process contributes to various health complications beyond infections, including cardiovascular diseases.

Primary Methods of Transmission

1. Sexual Contact:
   • The most common route of transmission is through unprotected sexual intercourse (vaginal or anal) with an infected partner. The virus can enter the body through mucous membranes found in the vagina, rectum, or urethra. Anal sex poses a higher risk due to potential tears in the rectal lining.
2. Sharing Needles:
   • Sharing needles or syringes for injecting drugs is another significant mode of transmission. Blood from an infected person can contaminate the equipment, allowing HIV to enter the bloodstream of another person.
3. Mother-to-Child Transmission:
   • HIV can be transmitted from an infected mother to her child during pregnancy, childbirth, or breastfeeding. This vertical transmission underscores the importance of screening and treatment for pregnant women living with HIV.
4. Blood Transfusions and Organ Transplants:
   • Although rare in countries with rigorous blood screening processes, HIV can be transmitted through transfusions of infected blood or organ transplants from an infected donor.
5. Other Routes:
   • Less common methods include deep open-mouth kissing (if both partners have bleeding gums) and severe bite trauma involving blood exposure; however, casual contact such as hugging or sharing utensils does not transmit HIV