Understanding HIV/AIDS and COVID-19 PDF

UNDERSTANDING HIV/AIDS AND COVID-19  INTRODUCTION TO HIV AND AIDS What is HIV? HIV (Human Immunodeficiency Virus) is a virus that attacks the body's immune system, specifically the CD4+ T cells (a type of white blood cell that helps regulate immune cells to fight infections). What...

UNDERSTANDING HIV/AIDS AND COVID-19  INTRODUCTION TO HIV AND AIDS What is HIV? HIV (Human Immunodeficiency Virus) is a virus that attacks the body's immune system, specifically the CD4+ T cells (a type of white blood cell that helps regulate immune cells to fight infections). What is AIDS? AIDS (Acquired Immunodeficiency Syndrome) is the final stage of HIV infection, where the immune system is severely damaged, and the body is vulnerable to infections and certain cancers. AIDS is not a disease itself but a group of symptoms caused by advanced HIV infection. Key Points: Without treatment, HIV can lead to AIDS, but with proper treatment (called ART), people with HIV can live long, healthy lives. HIV affects approximately 38 million people worldwide, with millions still lacking access to treatment. OVERVIEW OF HIV STRUCTURE HIV Structure: HIV is a virus, and like all viruses, it needs a host cell to reproduce. Key components of HIV: What is the viral genome of Human Immunodeficiency Virus (HIV)? 1.Gag forms group-specific protein antigens, and these proteins are named p24 and p18. 2.Env forms envelope proteins necessary for the interaction and presentation of target cells. These are gp120 and gp41. 3.Enzymes like reverse transcriptase (read RNA makes. DNA), protease (cut protein), integrase (allow viral DNA to integrate into host DNA) help the virus multiply inside the body. https://labpedia.net/human-immunodeficiency-virus-hiv-aids-acquired- immunodeficiency-syndrome/ PATHOGENESIS OF HIV INFECTION 1.Step-by-Step Process: Exposure to HIV: The virus is spread through bodily fluids (e.g., unprotected sex, sharing needles, or mother-to-child transmission during birth or breastfeeding). 2.Entry into the Body: HIV targets the immune system, specifically cells called CD4+ T cells. These cells help the body fight infections. 3.Viral Replication: Once inside the CD4+ T cell, HIV hijacks the cell’s machinery to make new copies of itself. 4.Immune System Breakdown: Over time, HIV destroys enough CD4+ T cells, weakening the immune system and leading to opportunistic infections (infections that occur more easily when the immune system is weak). 5.Progression to AIDS: If untreated, the immune system becomes severely compromised, and the person is at risk for AIDS. HOW HIV ENTERS WHITE BLOOD CELLS (CD4+ T CELLS) 1.How HIV Invades the Body: Attachment: HIV binds to the CD4 receptor on the surface of the T cell (this is the "lock" the virus fits into). 2.Co-receptor Binding: HIV also binds to another receptor on the T cell (called CCR5). Think of this like a second "key" that unlocks the door for the virus. 3.Fusion and Entry: The virus enters the T cell by fusing its outer layer with the cell membrane, allowing the viral RNA and enzymes to enter the cell and begin replication. HIV REPLICATION AND REVERSE TRANSCRIPTION 1.How HIV Reproduces Inside the Body:Reverse Transcription: HIV’s RNA (genetic material) is copied into DNA by an enzyme called reverse transcriptase. 2.Integration: The viral DNA is integrated into the host cell’s DNA using another enzyme called integrase. Once inside the host’s DNA, the virus can remain hidden (latent) or begin making new virus particles. 3.Replication: The host cell’s machinery starts producing new HIV RNA and proteins. 4.Assembly and Budding: New virus particles are assembled and leave the host cell (often killing it in the process) to infect other cells. ASSEMBLY AND BUDDING OF HIV How New Viruses Are Made: After replication, the HIV virus assembles its new components (RNA and proteins) inside the host cell. These new components move to the surface of the infected cell, where the virus buddies off from the cell membrane (like a new virus emerging from its "parent"). As the virus leaves the host cell, it takes a part of the host cell's membrane with it, forming its outer protective layer (envelope). https://labpedia.net/human-immunodeficiency-virus-hiv-aids-acquired-immunodeficiency-syndrome/ THE IMMUNE RESPONSE TO HIV How the Body Tries to Fight HIV: Innate Immune Response: The body's first line of defense involves cells like dendritic cells and macrophages, which try to detect and destroy HIV. Adaptive Immune Response: The body activates CD8+ T cells to kill infected cells, but because HIV targets CD4+ T cells (the cells that are supposed to help orchestrate this immune response), the overall immune response is weakened. Over time, the constant activation of the immune system by HIV leads to immune exhaustion, where the body can no longer fight infections effectively. CLINICAL STAGES OF HIV INFECTION HIV Stages: Acute HIV Infection: This is the initial stage of infection, often mistaken for the flu, with symptoms like fever, headache, and swollen lymph nodes. This is when the virus is replicating rapidly. Chronic HIV (Clinical Latency): HIV is still active but at low levels. People may not have symptoms for many years during this phase. AIDS (Advanced HIV Infection): The immune system is severely damaged. Opportunistic infections (like pneumonia, tuberculosis, or certain cancers) take advantage of the weakened immune system. SYMPTOMS OF AIDS Common Symptoms of AIDS: Opportunistic Infections: These include infections like Pneumocystis pneumonia (lung infection), tuberculosis (coughing and fever…วัณโรค), which are rare in healthy people but common in those with a weakened immune system. Malignancies: HIV increases the risk of certain cancers Neurological Effects: HIV can also affect the brain, leading to memory problems, confusion, or even HIV-associated dementia. DIAGNOSIS OF HIV/AIDS Testing for HIV:ELISA: A screening test that looks for antibodies against HIV. Western Blot: A confirmatory test for HIV antibodies. Viral Load Test: Measures the amount of HIV RNA in the blood and helps monitor how well ART is working. CD4 Count: Measures the number of CD4 cells in the blood, which indicates the strength of the immune system. Early detection and treatment can help manage the disease effectively. ANTIRETROVIRAL THERAPY (ART) What is ART?:ART (Antiretroviral Therapy) involves taking a combination of medicines that target different stages of the HIV lifecycle to prevent the virus from replicating. ART helps lower the viral load, restore the immune system, and reduce the risk of transmitting HIV to others. Adherence to ART is crucial: Missing doses can lead to resistance, where the virus no longer responds to treatment. https://labpedia.net/human-immunodeficiency-virus-hiv-aids-acquired-immunodeficiency- syndrome/ PREVENTION OF HIV/AIDS Preventive Measures: Safe Sex: Using condoms or dental dams to prevent the spread of HIV during sexual activity. Pre-exposure Prophylaxis (PrEP): A daily pill that reduces the risk of getting HIV for people at high risk. Post-exposure Prophylaxis (PEP): A 28-day course of antiretroviral drugs taken after possible exposure to prevent infection. Prophylaxis = prevention Severe Acute Respiratory Syndrome Corona Virus-2 causes disease COVID-19 https://en.wikipedia.org/wiki/COVID-19 INFECTION STEPS virion binds to the host cell receptor via its spike protein S subunit. The S-protein-receptor interaction determines the host species range and tissue tropism for the virus. For example, SARS-CoV utilizes angiotensin-converting enzyme 2 (ACE2) as the host receptor. After receptor binding, the virus gains access to the cytosol by acid-dependent proteolytic cleavage of the S protein into S1 and S2 subunits by a furin, cathepsin, TMPRSS2, or another protease, followed by S2-assisted fusion of the viral and cellular membranes (step1). After release of the viral genome (step 2), the replicase is translated from the genomic RNA (step 3). Viral RNA synthesis then follows ( step 4a), with the assembly of viral replication- transcription complexes (step 4b). Viral structural proteins (S, E, and M) are translated from the RNA (step 5), inserted into the endoplasmic reticulum (step 6) INFECTION STEPS Viral proteins move to the endoplasmic reticulum-Golgi intermediate compartment (ERGIC). Multiple copies of the nucleocapsid (N protein) package genomic RNA into helical structures (ribonucleoprotein complexes) in the cytoplasm, and interact with hydrophobic M proteins (envelope protein) in the ERGIC that serve to direct assembly of the virion (step 7). Virions budded from the membranes of the ERGIC (step 8) are then transported via the constitutive exocytic pathway out of the cell ( step 9)