HIV Flashcards
What is HIV?
Human Immunodeficiency Virus - attacks CD4 cells (T cells), reducing their number so the patient is more susceptible to infection and disease.
What is the main route of HIV spread in the UK?
Men who have sex with men (MSM).
What is the basic virology of HIV?
There are 2 distinct viruses HIV-1 and HIV-2.
Worldwide HIV-1 group M is predominant.
Attaches to cells with CD4 on surface lymphocyte (T-helper) and cells with certain chemokine receptors.
HIV is a retrovirus so inserts some of its RNA into DNA using reverse transcriptase.. This allows for virus diversity and ongoing opportunity to transmit.
Integrase facilitates integration into the host cell DNA.
Protease enzyme needed for mature virus progeny.
What are the stages of His infection?
Binding and entry Reverse transcription Integration Transcription Assembly Release and Protease
What are some laboratory tests for HIV?
To diagnose - HIV antigen/antibody testing.
To manage HIV infection - Viral load, HIV resistance testing, Avidity testing, Subtype determination, Tropism testing, drug levels.
What is meant by the window period?
The time during which markers of infection are not detectable.
What are some requirements of the Antibody/Antigen testing?
4th generation ELISA assay allows simultaneous detection of the antibody and antigen. The test window for this is 1 mont.
What is HIV resistance testing and how is it used?
Sequencing of polymerase and protease genes.
Identification of specific mutations that confer resistance to antiretroviral drugs.
Used for the baseline diagnosis, suboptimal treatment response, treatment failing, want to change treatment for another reason.
What is Tropism testing?
Tests which co-receptor the virus uses to enter CD4 cells.
Required before using a CCR5 antagonist.
What are some examples of body fluids that must be handled with the same amount of care as Blood when dealing with HIV infected individuals?
CSF Saliva Breast milk Amniotic fluid Vaginal secretions Semen Synovial fluid Exudate
