Blood Borne Viruses Flashcards
What are our current treatment capabilities for HIV?
No cure but can supress the infection leading to just a chronic infection without any progression or disability.
What’s the difference between world wide and UK risk of catching HIV?
Globally young women are much more at risk of catching HIV
In the UK, there is still a tendency for higher risk in MSM.
Are IVDU at a high risk of catching HIV from needles?
IVDU (intravenous drug users) have quite a low risk of contracting HIV.
What results in the illness in patients with HIV
Generally, people who have HIV will acquire infections from opportunistic pathogens that wouldn’t normally be able to cause an infection such as: a fungal infection in the mouth from candida albicans causing white patches all over the buccal cavity, small red rashes may appear on the skin due to malignancies caused by Herpes virus and another common infection is TB.
Which microorganisms are you particualry at risk from when you have HIV?
Because HIV causes immunosuppression you are much more at risk of infections from yeasts, moulds and protozoal infections.
How do HIV viruses replicate?
Retrovirus RNA DNA RNA before transcription takes place
Infects and replicated in mostly in T immune cells – CD4.
HIV replicates inside the cell utilising its machinery and destroys the cell as all the new viruses leave, many more viruses the go on to infect more cells.
How does the HIV gain entrance to the CD4+ cells?
Enveloped proteins bind to the CD4 receptors (CCR5 and CXCR4). Once bound it spills all its contents into the cytoplasm of the lymphocyte where the retrovirus replication takes place. DNA integrates into the cell’s DNA. All this is replicated and then the virus buds out and kills the cell in the process.
What are some of the important proteins for HIV to be successful in its host?
Integrase (into the cell DNA) reverse transcriptase and Viral protease enzyme are some of the important enzymes present in the viral RNA.
How does a HIV infection progress from initial infection?
Initially the body’s immune system manages to recover but doesn’t manage to kill it completely. Over the next few years you have latent infection and slowly CD4 count decreases whilst the viral load increases. Some people never progress from this stage but that is very rare. When CD4 becomes too low you begin to get serious infections (less than 200) at this point you have AIDS.
What effect does the viral load have on the host in general?
Can just get a generalised wasting syndrome due to the viral load.
What are the names of the different stages to infection from HIV?
The first phase is called the acute infection or seroconversion, after this the next stage is latent infection, stage 3 is symptomatic infection and finally severe infection/AIDS.
How is HIV transmitted?
Sexual transmission – vaginal, anal or oral. Sharing of injecting equipment. Vertical transmission when giving birth or feeding.
What factors effect HIV transmission?
Type of exposure, viral level, other STIs, whether the person they’re in contact with is on medication for the HIV as the risk of transferring HIV becomes negligible, condom use and breaks in skin or mucosa.
What is the prognosis for someone who is diagnosed with a HIV infection in the UK?
General life expectancy in the UK is about 77 years. Only if early detection, treatment, adherence, health living such as smoking, alcohol drugs and exercise. Late detection means worse prognosis.
What tests can be done for HIV?
Blood tests – HIV antigen and HIV antibody – result can come on the same day, must be after 4-6 weeks of infection, may get a false negative result if done too early.
Rapid tests – low cost and less than an hour before result. Blood test, oral, saliva. In home tests and postal testing. If negative quite accurate. May get false positive results so need to confirm.
