HIV Flashcards
HIV symptoms - in form of case study
42 year old female, UK born
HIV stats of the UK
103,800 total
What is HIV
Discovered in 1984
It’s a retrovirus “backwards” - goes from ssRNA —>
DNA —> ssRNA
It works by infecting cells with a CD4 surface receptor
HIV replicates inside cells
Destroys the cell, which causes inflammation, which means the virus spreads/ infects more cells
Mechanism of invasion of HIV
1) Free HIV virus
2) Binding and fusion - virus binds to a CD4 molecule and a co-receptor CCR5. Receptor molecules are common on he cell surface - virus then fuses with the cell
3) infection - virus penetrates cell - contents emptied into the cell
4) Reverse transcription - single strands or viral RNA are converted into double stranded DNA by the reverse transcriptase enzyme
5) integration - viral DNA is combined with the cell’s own DNA by the integrate enzyme
6) Transcription - when the infected cell divides, the viral DNA is ‘read’ and long chains of proteins are made
7) assembly - sets of viral protein chains come together
8) budding - immature virus pushes out of the cell taking some of the cell membrane with it
9) immature virus breaks free of the infected cell
10) maturation - protein chains in the new viral particle are cut by the protease enzyme into individual proteins that combine to make a working virus
Transmission
Contact of infected bodily fluids with mucosal tissue/ blood/ broken skin e.g. sex
Could be transferred using medical procedures - blood to blood products, skin grafts or organ donations
Can transfer from parents to child - during delivery through an infected birth canal, as a result of ingestion of breast milk carrying the virus
Acute HIV symptoms
Fever, weight loss, Sores in mouth / thrush
Esophagus sores
Hepato+splenomegaly
Nausea and vomiting
Rash on skin
Lymphadenopathy
Headaches and Neuropathy
Image shows type of infection that occur with decreasing T Cell count (originally in the 1st 2 months, T cell dips, then as virus stables the T count increases to try and deal with the infection, then after years it will start to plummet)
Conditions associated with severe HIV
Brain - Cryptococcal meningitis, toxoplasmosis
Eyes - CMV
Mouth and throat - cold sores and ulcers and thrush
Blood - hyperglycaemia and dislipidaemia (abnormal lipid levels)
Lungs - PCP and TB
Bone - Osteoporosis
Heart - heart diseases stroke
Liver - HCV
Stomach - CMV
Reproductive system - genital ulcers, HPV, pelvic inflammatory disease, vaginal yeast infections
Body - HIV wasting syndrome
Factors affecting HIV transmission
Type of exposure
type of sexual act
Living with HIV in the UK
Life expectancy and quality of life is now excellent 90;90;90
General population - life expectancy is approximately 80 years
HIV +ve = 78 years
with early detection/ good CD4
treatment + adherence to treatment
healthy living (not smoking or drinking or being overweight)
Late detection leads to a worse prognosis
HIV - tests and treatments
Diagnostic tests:
Blood tests - serology - check for -
HIV antigen (Ag) - viral protein
HIV antibody (Ab) - immunoglobulin - immune response to antigen
Current test - detects both AG and Ab and can be found positive in 4 weeks - may get a false negative result - (you have it but test said you didn’t)
Blood tests - PCR -
Detects HIV nucleic acid - highly sensitive for it
Detects very early infection
Expensive
Not used for initial HIV testing
Used for follow-up/ treatment response
Rapid tests - low cost - <1 hr
Usually detect he HIV antibody
E.g. blood test, oral test - can be done at home
If negative its accurate
May get a false positive - need to confirm with serology
Who should be tested?
Aims of HIV treatment
Using - Antiviral retrovirus drugs
Reconstitute CD4 count /immune system
Which anti-retrovirals to use?
Non nucleoside / Nucleoside Reverse transcriptase inhibitors (NNRTI/NRTI) - Tenofovir
Protease inhibitors - Doravirine
Integrate inhibitors - Darunavir
Why give 3 ARV’s?:
Millions of rounds of viral replication each day
Strategies and ethical dilemmas in HIV
Strategies - Increase condom usage
