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What are five requirements for the transmission of HIV?
- Infected host
- Infectious viral particles
- Bolus of infected particles
- Target cells
- Immune system avoidance
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Describe Immune system avoidance as on requirement for trasmission of HIV.
HIV reproduces by the millions each day, this can quickly overwhelm the immune system.
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What are the three most common transmission sources for HIV? What is the most concentrated source?
- Most common: blood, semen, breast milk
- Most concentrated: cerebrospinal fluid
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What are the two most commonly affected cells?
CD4 lymphocytes and macrophages
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What are three ways vertical transmission can occur and their percentages.
- 1. In utero 30%
- 2. Intrapartum (during birth) 60%
- 3. Breast feeding -no %
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What must a cell have in order to be infected with HIV?
A CD4 and chemokine (CCR5/CXCR4) receptor.
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Which glycoprotein of HIVs is responsible for binding and which is responsible for fusion?
- gp120 = binding
- pg41 = fusion
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What are the steps of viral replication?
- 1. Sheds matrix/exposes vRNA
- 2. Reverse transcriptase changes vRNA to vDNA
- 3. Both are mixed via Integrase
- 4. mRNA tells ribosomes to make proteins/enzymes for vDNA synthesis
- 5. Viral assembly - protease cuts polypeptides to size
- 6. buds off and kills cell
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What are the three strains of HIV?
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Describe M-tropic strain
- also called macrophage tropic
- prominent early in the infection
- binds to CCR5
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Describe T-tropic strain.
- also called T-lymphocyte
- prominent later in the infection stage
- most virulent
- binds to CXCR4 chemokine
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What is the normal CD4 count?
1000
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Describe the clinical course during the first 4-8 weeks of infection.
- Plasma viral level spike causing a drop in CD4 cells
- HIV specific T-cells and envelope antibodies are created which help increase and slow the loss of CD4 cells
- patient experiences flu-like symptoms
- can also develop PGL (Persistent Generalized Lymphadenopathy
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Describe Persistent Generalized Lymphadenopathy
- Commonly developed within the first 4-8 weeks of infection and can persist throughout infection
- characterized by swollen lymph nodes throughout the body because the body is consistently trying to fight off infection
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Define seroconversion.
The production of antibodies in response to an antigen.
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Describe the importance of the seroconversion during the first few weeks/months of infection.
The seroconversion goes from sero-negative (no detectable antibodies to sero-positive (detectable antibodies), however between this there is a window period where you can test negative when you are really positive. That is why multiple test should be done.
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Describe the viral set point during the clinical course of HIV.
The viral set point is when the immune response and the viral load stabilize. There is a clinically latent period where no signs/symptoms may appear, however CD4 cells continue to drop.
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What type of test is the ELISA and what does it stand for?
the ELISA, enzyme-linked immunosorbent assays is a screening antibody test
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What is an example of a confirmatory antibody test?
Western Blot
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What is the most common opportunistic infection with HIV?
Pneumocystis jirovecii pneumonia (PJP)
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Describe Cryptococcus neoformans.
- meningitis in 10%
- fungal
- increase in lymphocytes and proteins, decreased glucose
- fever, nausea and vomiting
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Describe Candida albicans
- fungal
- causes oral thrush
- can be found in esophagus and bronchi
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Describe Cytomegalovirus (CMV)
- herpes simplex causes severe lung disease
- can also cause chorioretinitis and blindness
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If an AIDS patient goes blind, what is most likely the cause?
CMV
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If an AIDS patient develops oral thrush, what is most likely the cause?
Candida albicans
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If an AIDS patient shows a lumbar puncture with an increase in lymphocytes and proteins and a decrease in glucose, what is most likely the cause?
Cryptococcus neoformans
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Describe Kaposi's sarcoma.
a malignant vascular tumor common in AIDS patients, characterized by red-purple plaques or nodules the arise on the skin on all parts of the body, most likely due to Herpes simplex B.
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List two malignancies that may arise from HIV.
- Kaposi's sarcoma
- CNS lymphoma
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What is HIV encephalopathy also called?
AIDS dementia
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Describe Mycrobacterium avium inracellulare (MAI).
- major systemic baacterial infections seen in AIDS (later in infection)
- presents with fever, night sweats, diarrhea, and elevated liver function test
- bacteria disseminate throughout the body, causing the wasting. KEY WORD: WASTING
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