S8) Blood Borne Viruses – HIV Flashcards
What are some key signs of HIV?
- Oral candidiasis
- Kaposi’s sarcoma
- PCP (Pneumocystis pneumonia)
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In terms of infection model, outline the possible outcomes for a patient with HIV
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Describe HIV acquisition by risk group
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Which parts of England have had the biggest increases in HIV transmission in the last 10 years?
- East of England
- North East
- Midlands
Identify and describe the 4 key features in viral structure and behaviour
- Genome – RNA or DNA (ss/ds)
- Capsid – protein shell, protects the genome (helical/icosahedral)
- Lipid envelope – derived from host cell membranes (present/absent)
- Replication strategy
What is the Human Immunodeficiency Virus?
- HIV is a retrovirus which infects cells with CD4+ surface receptor (T-helper cells, monocytes / macrophages)
- It replicates inside cells, destroys the cell, causes inflammation and spreads to / infects more cells
How is HIV transmitted?
Transmission through contact of infected bodily fluids with mucosal tissue / blood / broken skin
What are the 5 different ways in which HIV can be transmitted?
- Sexual contact
- Transfusion
- Contaminated needles
- Medical procedures (organ donation, skin grafts, blood products)
- Perinatal transmission (transplacental, during delivery, through ingestion of breast milk)
Outline the 7 steps involved in retroviral replication
⇒ Virus binds to a CD4+ on cell surface & fuses with cell
⇒ Virus penetrates & empties contents into cell (infection)
⇒ Viral ssRNA → dsDNA by reverse transcriptase
⇒ Viral DNA is integrated into host’s DNA by integrase
⇒ Viral DNA is transcripted during infected cell division
⇒ Viral protein chains assemble & bud out of cell (immature – breaks free)
⇒ Virus matures as protein chains are cut by protease
Outline the 4 different phases of an HIV infection in terms of CD4+ count and viral load
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Identify the different stages of HIV, in terms of the symptoms and CD4 count
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What are the main symptoms of Acute HIV infection, with regards to the following areas:
- Systemic
- Lymph nodes
- Skin
- Gastric
- Muscle
- Mouth
- Lymph nodes – lymphadenopathy
- Skin – rash
- Muscles – myalgia
- Systemic – fever, weight loss
- Gastric – nausea, vomiting
- Mouth – sores, thrush
What are the factors affecting HIV transmission?
- Type of exposure – type of sexual act, transfusion / needlestick / mucous membrane
- Viral level in blood
- Condom use
- Breaks in skin/mucosa – other STI / sexual assault
What are 4 factors which enable people with HIV to live healthy lives?
- Early detection
- Treatment
- Adherence
- Healthy living
Outline Serology as a diagnostic test for HIV
- Detects HIV antigen (Ag) and HIV antibody (Ab)
- Result on same day
- May get false negative result (if performed too early –wait 4 weeks)