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hiv algorism 2022

1. Title Slide Introduction to HIV/AIDS Pathogenesis and Immunology

2. Learning Objectives - Describe the function of the immune system. - Explain the pathophysiology of HIV. - Discuss the HIV life cycle. - Explain how HIV evolves and its association with opportunistic infections (OIs).

3. Understanding the Immune System The immune system defends the body from infections through: - Innate immunity (immediate response) - Adaptive immunity (long-term response)

4. Innate Immunity Examples include: - Skin as a barrier - Stomach acidity

5. Adaptive Immunity Examples include: - Antibodies produced by B-lymphocytes - T-lymphocyte response

6. Key Immune Organs Includes: - Thymus - Bone marrow - Lymph nodes - Spleen - Mucosal-associated lymphoid tissues

7. How HIV Infects Cells? How HIV Infects Cells? HIV stands for Human Immunodeficiency Virus. Viruses are simple in structure and cannot replicate alone and thus they require the components of other cells to replicate ..

8. .. HIV, like all viruses, must therefore enter other cells if they are to replicate and survive. HIV is from a special family of viruses known as retroviruses

9. Modes of HIV Transmission - Sexual contact - Blood and body fluids - Mother to child - Percutaneous exposure

10. HIV Target Cells HIV targets CD4 cells found in: - T-cells - Monocyte-macrophage cell lines

11. HIV and the Immune System HIV destroys CD4 cells, weakening the immune system and exposing the body to opportunistic infections.

12. Stages of the HIV Life Cycle - Attachment - Reverse Transcription - Integration - Production - Assembly - Release

13. HIV Life Cycle Stage 1 Attachment: HIV attaches to CD4 cells and releases RNA and enzymes.

14. HIV Life Cycle Stage 2 Reverse Transcription: The enzyme reverse transcriptase creates DNA from viral RNA.

15. HIV Life Cycle Stage 3 Integration: Viral DNA integrates into the host cell nucleus using integrase.

16. HIV Life Cycle Stage Production: New viral components are produced using the host cell's machinery. Assembly: Viral components are assembled using the protease enzyme.

17. HIV Life Cycle Stage 6 Release: New viruses are released to infect other CD4 cells.

18. Immune Damage by HIV CD4 count assesses immune system strength. A CD4 count between 450-1500 cells/mm3 indicates the immune system is coping well A low CD4 count tells us the immune system is weak - Viral load indicates infection activity .

19. HIV Clinical Course Stages include: 1. Primary infection 2. Latent stage 3. AIDS

20. Primary HIV Infection Patients develop nonspecific ‘flu-like’ symptoms like - Fever - Fatigue - Pharyngitis - Rash

21. During primary infection, the patient could be negative for HIV specific antibodies despite the presence of infection. This stage is called window period and is characterized by very high viral load signifying extreme infectiousness despite false negative antibody result.

22. The switch from antibody negative to antibody positive is called sero -conversion and most patients sero -convert within 3 months after exposure to the virus. Clinical management includes symptomatic treatment, counseling for risk reduction and repeat antibody testing. Patients are most likely to transmit HIV during the early stage of infection.

23. Asymptomatic Stage During the first years of infection, the immune system-although weakened a bit by the HIV virus - still functions quite well. The infected person will have no symptoms, or only minor symptoms like skin diseases, a little loss of weight, or repeated sinusitis.

24. A lot of people do not know they are HIV+ at this stage The immune system manages to control HIV during this stage, which can last 10 years.

25. Progression to AIDS Occurs when the immune system is severely weakened, leading to opportunistic infections.

26. 2. Rapid progressors account for 5% of individuals who develop AIDS within 3 years. The viral set point is high in this group. 3. Long term non- progressors account for 10% individuals will have stable CD4 count for more than 8 years. The viral set point is remarkably low In this group

27. For Paediatric HIV infected populations, the following patterns are usually observed. Category 1 (25–30%): Rapid progressors , who die by the age of one and who are thought to have acquired the infection in utero or during the early perinatal period.

28. Category 2 (50–60%): Children who develop symptoms early in life, followed by a downhill course and death by the age of three to five. Category 3 (5–25%): Long-term survivors, who live beyond the age of eig

29. CD4 Count and OI Risk CD4 levels: - >450 cells/mm³: Good immune defense - <200 cells/mm³: Severe risk of OIs

30. Association Between CD4 and OIs Illustration of the relationship between CD4 count and opportunistic infections.

31. Summary of HIV Pathophysiology - Infects CD4 cells - Uses them for replication - Weakens immune defense