HIV and AIDS Flashcards
(45 cards)
What is HIV?
Human immunodeficiency virus, a virus that targets cells within the immune system causing it to fail
What is AIDS?
Acquired immunodeficiency syndrome, describes the complications that occur when an immune system fails
Where is the highest prevalence of HIV/AIDS?
Sub-Saharan Africa contains 2/3 of all people in the world living with HIV/AIDS
What is the main route of HIV infection in the UK?
homosexual sexual transmission is main route and injecting drug use is low route
What sex is HIV more common in in the UK?
M>F
What sex is HIV more common in in Africa?
F>M
Name the routes of infection for HIV
Main route of spread varies geographically
Sexual transmission
Intravenous drug misuse
Organ transplant
Vertical transmission/Mother-to-child
Unscreened blood/blood products
Which of the two types of HIV virus is most predominant?
HIV-1
What type of virus is HIV?
Single stranded RNA retrovirus
Describe the basic virology of HIV?
Virus targets cells with CD4 molecule, such as lymphocytes/T helper cells, dendritic cells and macrophages
HIV attaches to CD4 molecule and then a co-receptor via GP120 protein to gain access into cell
Once HIV is in the cell, RNA is converted to DNA using reverse transcriptase
The lack of accuracy during replication leads to virus diversity which leads to persistent infection of the cell and the ongoing opportunity to transmit
What are the 5 steps of HIV/AIDS (natural history of HIV)?
Acute infection/seroconversion
Asymptomatic
HIV related illness
AIDS defining illness
Death
What is the diagnostic window?
The window period is the time during which markers of infection are not detectable.
Testing during this period for antibody/antigen can result in false negative results
What viral labartory tests are used in HIV diagnosis?
Antigen and antibody tests
- ELISA allows simultaneous detection of antibody and antigen
RNA/DNA test
- Confirmatory test
What investigations, except diagnostic lab tests, are used in HIV diagnosis and monitoring?
Viral load/HIV genome Detection
CD4 Count
HIV Resistance Testing
Avidity testing
Subtype determination
Tropism testing, determinswhich co-receptor the virus used to enter CD4 cells
Drug levels, to determine compliance
When should HIV testing for asymptomatic patients be done?
4 weeks post possible exposure
When should HIV testing for asymptomatic patients be repeated?
12 weeks
What happens to viral loads and CD4 count when treatment is initiated?
When a patient initiates antiretroviral treatment, their viral load will fall and their CD4 count will rise
What is a normal CD4 count?
>500
What CD4 count is diagnostic of AIDS?
<200
How does acute HIV/seroconversion illness present?
Flu-like illness
Fever
Malaise and lethargy
Pharyngitis
Lymphadenopathy
Toxic exanthema (widespread rash)
When does seroconversion illness occur?
Occurs when antibodies first develop at 2-4 weeks post-exposure
How long does seroconversion illness last?
lasting for 1-2 weeks
What percentage of patients experience seroconversion illness?
30-60% of patients
Give examples of HIV related illness
Oral Thrush/candida Albicans
Unexplained weight loss
Unexplained lymphadenopathy
Guillain-Barre
Dementia
Aspergillosis
Anal or lung Cancer
