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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
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.
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
What are the two most commonly affected cells?
CD4 lymphocytes and macrophages
What are three ways vertical transmission can occur and their percentages.
- 1. In utero 30%
- 2. Intrapartum (during birth) 60%
- 3. Breast feeding -no %
What must a cell have in order to be infected with HIV?
A CD4 and chemokine (CCR5/CXCR4) receptor.
Which glycoprotein of HIVs is responsible for binding and which is responsible for fusion?
- gp120 = binding
- pg41 = fusion
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
What are the three strains of HIV?
Describe M-tropic strain
- also called macrophage tropic
- prominent early in the infection
- binds to CCR5
Describe T-tropic strain.
- also called T-lymphocyte
- prominent later in the infection stage
- most virulent
- binds to CXCR4 chemokine
What is the normal CD4 count?
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
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
The production of antibodies in response to an antigen.
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.
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.
What type of test is the ELISA and what does it stand for?
the ELISA, enzyme-linked immunosorbent assays is a screening antibody test
What is an example of a confirmatory antibody test?
What is the most common opportunistic infection with HIV?
Pneumocystis jirovecii pneumonia (PJP)
Describe Cryptococcus neoformans.
- meningitis in 10%
- increase in lymphocytes and proteins, decreased glucose
- fever, nausea and vomiting
Describe Candida albicans
- causes oral thrush
- can be found in esophagus and bronchi
Describe Cytomegalovirus (CMV)
- herpes simplex causes severe lung disease
- can also cause chorioretinitis and blindness
If an AIDS patient goes blind, what is most likely the cause?
If an AIDS patient develops oral thrush, what is most likely the cause?
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?
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.
List two malignancies that may arise from HIV.
- Kaposi's sarcoma
- CNS lymphoma
What is HIV encephalopathy also called?
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