Podcast
Questions and Answers
Why is the asymptomatic stage of HIV infection particularly insidious?
Why is the asymptomatic stage of HIV infection particularly insidious?
- Medications are ineffective during this stage, allowing the virus to develop resistance.
- The virus exclusively targets non-immune cells, making it difficult to detect through standard blood tests.
- During this stage, the virus is completely dormant, preventing effective treatment strategies.
- The lack of noticeable symptoms leads to delayed diagnosis and continued viral replication, causing progressive immune system damage. (correct)
How do genetic mutations in the CCR5 receptor provide resistance or immunity to HIV?
How do genetic mutations in the CCR5 receptor provide resistance or immunity to HIV?
- Mutations in CCR5 enhance the immune response by increasing the production of antibodies.
- Mutations in CCR5 cause infected cells to self-destruct, limiting viral spread.
- Mutations in CCR5 prevent HIV from effectively binding and entering immune cells, thus hindering infection. (correct)
- Mutations in CCR5 alter the virus's ability to replicate within cells, slowing disease progression.
What is the role of the enzyme reverse transcriptase in the pathogenesis of HIV, and why is this mechanism significant?
What is the role of the enzyme reverse transcriptase in the pathogenesis of HIV, and why is this mechanism significant?
- Reverse transcriptase enhances the immune response by producing antibodies that target infected cells.
- Reverse transcriptase repairs damaged host cell DNA, preventing viral integration and slowing disease progression.
- Reverse transcriptase facilitates the direct integration of viral RNA into the host cell's DNA, causing immediate cell death.
- Reverse transcriptase converts HIV's RNA into DNA, allowing the virus to integrate into the host cell's genome and replicate. (correct)
How does HIV exploit the immune system to replicate itself, and why is this considered a 'sneaky' mechanism?
How does HIV exploit the immune system to replicate itself, and why is this considered a 'sneaky' mechanism?
Why is HIV tropism significant in understanding the progression and treatment of HIV infection?
Why is HIV tropism significant in understanding the progression and treatment of HIV infection?
During the acute phase of HIV infection, the R5 strain of the virus infects cells in the epithelial or mucosal tissues. How does this initial infection strategy contribute to the establishment of chronic HIV?
During the acute phase of HIV infection, the R5 strain of the virus infects cells in the epithelial or mucosal tissues. How does this initial infection strategy contribute to the establishment of chronic HIV?
How does the development of the X4 strain of HIV during the chronic phase accelerate immune system depletion, and what implications does this have for disease progression?
How does the development of the X4 strain of HIV during the chronic phase accelerate immune system depletion, and what implications does this have for disease progression?
Which of the following scenarios best illustrates the concept of HIV as a multifactorial disease?
Which of the following scenarios best illustrates the concept of HIV as a multifactorial disease?
How does the presence of oral hairy leukoplakia during the chronic phase of HIV infection indicate a decline in immune function?
How does the presence of oral hairy leukoplakia during the chronic phase of HIV infection indicate a decline in immune function?
Why is it crucial for individuals with HIV to be aware of their infection status, considering the global epidemiology of the virus?
Why is it crucial for individuals with HIV to be aware of their infection status, considering the global epidemiology of the virus?
Flashcards
HIV (Human Immunodeficiency Virus)
HIV (Human Immunodeficiency Virus)
A virus that targets cells in the immune system, leading to immunodeficiency and increasing the risk of infections and tumors.
AIDS (Acquired Immunodeficiency Syndrome)
AIDS (Acquired Immunodeficiency Syndrome)
The final stage of HIV infection, characterized by a severely compromised immune system, making the body susceptible to opportunistic infections and cancers.
Seroconversion
Seroconversion
The process where the body generates detectable antibodies in response to a virus, indicating an infection.
CD4-positive T Cells
CD4-positive T Cells
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GP120
GP120
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Viral Tropism
Viral Tropism
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Reverse Transcriptase
Reverse Transcriptase
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Lymphadenopathy
Lymphadenopathy
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Opportunistic Infections
Opportunistic Infections
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Study Notes
HIV/AIDS Overview
- HIV officially identified in 1983 and considered a zoonotic disease
- Originated from a subspecies of chimpanzee native to West Africa
- Transmission is multifactorial, spreading through migration, travel, sexual practices, drug use, and war
- HIV targets CD4-positive T cells, leading to Acquired Immunodeficiency Syndrome (AIDS)
Stages of HIV/AIDS Infection
- Primary/Acute HIV Infection: Highly infectious, but may not be detectable early on
- Window Period: 2-12 weeks for the body to generate detectable antibodies (seroconversion)
- Seroconversion: Immune system produces enough antibodies to be detected by an HIV test, signaling presence of the virus
- Asymptomatic Stage (Clinical Latency): Person feels well, but the virus multiplies and destroys immune cells
- Symptomatic Stage: Clinical manifestations appear, such as fever and swollen lymph nodes
- Full-blown AIDS: Severe immune compromise with high susceptibility to infections/cancers; CD4 count drops below 200 cells/mm³
HIV/AIDS Statistics
- In the US, approximately 1.2 million people are living with HIV, with 168,000 unaware of their infection
- Globally, most individuals with HIV remain undiagnosed
- HIV incidence in the US has remained steady at about 50,000 new cases per year
- Stabilization indicates positive progress due to effective HIV medications
Pathogenesis of HIV
- HIV targets CD4-positive T cells, impacting adaptive immune response and humoral immunity
- Acute Infection: HIV infects CD4-positive T cells, causing a temporary spike in replication
- Symptoms: Nausea, vomiting, flu-like symptoms, weight loss, and general infections
- AIDS Diagnosis: CD4 count falls below 200 cells/mm³, indicating severe immune loss
- At risk for opportunistic infections such as pneumonia and cancers
Transmission Routes
- Sexual contact (vaginal, anal, or oral sex)
- Sharing needles for intravenous drug use
- Mother to baby during pregnancy, childbirth, or breastfeeding
Mechanism of HIV Infection
- HIV: RNA retrovirus that targets immune system cells (CD4-positive T cells, macrophages, dendritic cells)
- GP120: Protein used by HIV to attach to the CD4 molecule on the surface of cells
- Co-receptors: Virus binds to either CXCR4 or CCR5 to enter the cell
- Genetic Mutations: Some individuals have mutations in the CCR5 receptor that make them immune or slow disease progression
- Reverse Transcriptase: Enzyme used to convert viral RNA into double-stranded DNA for integration into the host cell’s genome, turning the host cell into a virus factory
Viral Tropism and Disease Progression
- Viral tropism: Virus's ability to target specific cell types
- Acute infection: R5 strain of HIV infects cells in the epithelial or mucosal tissues, leading to high viral replication
- Immune response: Viral load reduces over several weeks, but the virus is still detectable
- Chronic Phase: Virus continues to replicate in the body at lower levels
- T cell counts decline gradually from 1-2 billion T cells/day
Clinical Manifestations During Chronic HIV
- Lymphadenopathy (swollen lymph nodes)
- Oral candidiasis (yeast infection in the mouth)
- Oral hairy leukoplakia (white patches on the tongue)
- CD4 counts drop below 200 cells/mm³, patients experience more severe symptoms, including opportunistic infections and the development of AIDS
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