Infection 3 HIV Flashcards
Structures of a virus
Genome - RNA/DNA
Capsid - protein cell
Lipid envelope- yes/no
Replication strategy
Shapes of capsid in virus
Helical - rod shaped or coiled
Icosahedral - spherical
What is the capsid in a virus?
Protein shell which protects the genome
How does HIV infect the cell?
Infects with CD4 surface receptor
Replicates inside the cell - destroys cell
- causes inflammation
- infects more cells
Modes of transmission of HIV
Contact of infected bodily fluids
Medical procedures e.g. skin graft, organ donation
Sexual contact
Mother to baby
Contaminated needles
HIV symptoms
oral candidiasis
Kaposi’s sarcoma
PCP - pneumocystis pneumonia
Fever
Weight loss
Malaise
Headache
Thrush
Rash
Nausea + vomiting
Sores in mouth + oesophagus
Two types of test for HIV
Blood tests
Rapid tests
Two types of blood tests for HIV
Serology
PCR
What does HIV serology detect?
HIV antigens Ag
HIV antibodies Ab
Speed of serology
Same day result
Are false negatives/positives possible in serology?
False negative possible
What does HIV PCR detect?
HIV nucleic acid
highly sensitive - detects early infection
What is PCR used for in HIV testing?
Follow up/treatment response
What do rapid HIV test detect?
HIV antibody in blood and saliva
What do you use for rapid HIV tests?
Blood test - finger prick
Oral - saliva
At home testing
What do you do if you get positive or negative rapid HIV test?
Negative - accurate
Positive - confirm with serology
Treatment of HIV
No cure - management needed
Anti-retroviral drugs
Testing + screening
Condom usage
PrEP - pre exposure prophylaxis
PEP - post exposure prophylaxis
How are anti-retroviral drugs used in HIV?
Mix 2 nucleoside reverse transcriptase inhibitor with one of: protease inhibitor OR integrate inhibitor OR CCR5 inhibitor
Reason for anti-retroviral drugs mixing
To overcome drug resistance + viral mutations
what is HIV?
- a ssRNA retrovirus which infects cells with CD4+ surface receptors
- replicates inside cell»_space; destroys cell, causes inflammation + spreading
outline retrovirus replication
- virus binds to CD4+ on cell surface
- virus penetrates + infects cell
- viral ssRNA > dsDNA by reverse transcriptase
- viral DNA is integrated into host DNA by integrase
- viral DNA is transcripted during cell division
- viral protein chain assemble + bud out of cell
- virus matures as chain is cut by proteases
what are the main symptoms of acute HIV infection regarding:
- systemic
- lymph nodes
- skin
- gastric
- muscle
- mouth
- systemic - weight loss, fever
- lymph nodes - lymphadenopathy
- skin - rash, Kaposi’s sarcoma
- gastric - nausea, vomiting
- muscle - myalgia (pain)
- mouth - sore, thrush
what factors affect HIV transmission?
condom usage
type of exposure
breaks in skin
viral level in blood
what 4 factors allow people with HIV to live healthy lives?
- early detection
- treatment
- adherence
- healthy living
aims of HIV treatment
reduce general inflammation
reduce risk of transmission
normalise lifespan + QoL
reconstitute CD4 count
Is HIV single/double stranded + RNA or DNA?
Single stranded RNA
What is the most common opportunistic infection in a patient with HIV?
Pnuemocystis jiroveci
What count of CD4+ leads to progression into AIDs?
<200
