HIV Flashcards
risk factor groups of HIV
-heroin addicts
-homosexuals
-haemophiliacs
-haitains
what type of virus is hiv
retrovirus OF THE LENTIVIRUS GENUS
what cells does hiv attack
cd4+ receptors on cells such as macrophages, t helper cells and dendritic cells
two types of HIV
HIV1- US and worldwide
HIV2- MORE RARE, western africa
STRUCTURE OF HIV
Spherical in shape
- 2 copies of single stranded rna
- enclosed with a capsid of viral protein p24
how can hiv be spread/ transmitted
- contact of infected bodily fluids
- sharing of IV needles
- medical procedures, skin grafts, organ donations
- pregnancy/ during delivery
names of the stages of the viral replication
attachment
cell entry
interaction with host cells
replication
assembly
release
describes the stages of HIV replication
-HIV attaches to cd4+ receptors using a co receptor such as gp120
-entry into cell and combines into host cells genome using viral integrase enzyme
- virus undergoes reverse transcription and sIngle strands of viral RNA are converted to double stranded DNA
- virion is then assembled, buds and leave the host cell ready to infect other cells
main symptoms of acute HIV
- FEVER
-oral candidiasis
-swollen lymph nodes
what is a lentivirus
represents a genus of slow viruses with a long incubation period
what cells are mostly affected by hiv
CD4 T CELLS
macrophages
dendritic cells
immune system response to HIV
- neutralises antibodies , but poor and slow to develop
cd8- cause an early decline in virus but virus escapes through mutations
main immune system effect from hiv
progressive decline in number and function of CD4 LYMPHOCYTES
mechanisms of cd4+ lymphocyte depletion
- direct cytotoxicity of directly infected cells
- activate induced death
- decrease in production
-redistribution - bystander cell killing
socio-economic impact of
HIV/AIDS in Africa
- low life expectancty
- loss of economic workers
-increased spending on healthcare
-distortion of healthcare spending - stigma of hiv
When does HIV become AIDS
WHEN the cd4 is less than <200 cells per ml
what problems arise when developing an immune response to HIV
- low neutralising antibodies and variability of gp120 means antibodies cant keep up with production
- glycoprotein envelope shows genetic diversity
- failure of cd4+ proliferation
two markers used to monitor HIV infection
cd4+ cell count
HIV viral load
what to do with patient with fever , rash + non specific symptoms
1- take a sexual history
2- think of hiv
3- tell lab and check for antigen
how to prevent HIV
Circumcision - reduced ability of HIV to penetrate
STI control
Vaccines
HIV diagnosis
types of hiv tests
point of care tests
venous blood samples
home testing kits
treatments for HIV
Nucleoside reverse transcriptase inhibitors ( NRTI) and either a protease inhibitor or NNRTI
what does HAART involve
act on different proteins in replication cycle to suppress viral replication
two main methods that hiv develops drug resistance
non adherence
drug-drug interactions
main immunological changes seen in progressive HIV
reduction in CD4 count
increase B2-microglobulin
decreased IL-2 production
polyclonal B-cell activation
decrease NK cell function
reduced delayed hypersensitivity responses
Examples of an nnrti
nevirapine
