How is the defense systems destroyed by this deadly virus of AIDS?
1. Initial Infection: HIV enters the body through contact with infected bodily fluids, such as blood, semen, vaginal fluids, or breast milk. Once inside, it infects CD4+ T cells and uses their cellular machinery to replicate and produce more copies of the virus.
2. Replication and Spread: The replicated viruses are then released from the infected CD4+ T cells, infecting new healthy CD4+ T cells and other immune cells. This cycle of infection and replication leads to a progressive decline in the number of functional CD4+ T cells, weakening the immune system's ability to fight off infections.
3. Immune System Compromise: As the number of CD4+ T cells drops below critical levels, the immune system becomes severely compromised, making the person vulnerable to a wide range of opportunistic infections (OIs) and certain types of cancers. These OIs can include infections like Pneumocystis jirovecii pneumonia (PCP), Mycobacterium avium complex (MAC), candidiasis, cryptosporidiosis, toxoplasmosis, and Kaposi's sarcoma, among others.
4. Secondary Infections and Diseases: The weakened immune system's inability to effectively combat these opportunistic infections and diseases leads to their progression and, in some cases, can be life-threatening. AIDS is defined when an HIV-infected individual develops certain OIs or AIDS-defining cancers.
5. HIV Latency and Reactivation: HIV can also enter a latent phase, during which the virus remains dormant within certain cells. This makes it harder for the immune system to recognize and eliminate the virus. However, under certain conditions, such as a weakened immune system or changes in the cellular environment, latent HIV can be reactivated, leading to new rounds of infection and immune system damage.
Overall, HIV's primary destructive effect is on the body's immune system, specifically CD4+ T cells, leading to a weakened defense against various infections and diseases, eventually progressing to AIDS. Understanding the mechanisms by which HIV destroys the defense systems is crucial for developing effective treatments and interventions to manage HIV and prevent the development of AIDS.