11) Blood Borne Viruses Flashcards
(32 cards)
What are some signs of HIV?
Oral candidiasis - white sores
Kaposi’s sarcoma - red blotches on skin
Pneumocystis pneumonia (PCP) - interstitial markings on lung
Globally, who is HIV more common in?
Women
Heterosexuals
What cells does HIV infect?
CD4+ T cells
What type of virus is HIV?
Retrovirus
What enzymes does HIV use in its pathogenesis?
Reverse transcriptase - RNA to DNA
Intergrase - Incorporate its DNA into cell DNA
Describe the pathogenesis on HIV:
Binds to CD4 receptor and empties contents into cell
Reverse transcriptase and intergrase allowing transcription
Assembly of viral proteins
Budding of virus out of cell
Maturation - protease cuts protein chains to make working virus
Describe HIV’s effect on CD4+ numbers:
Acute infection causes reduction in CD4+
Then, goes latent as CD4+ recovers
Viral load rises again and severe infection/AIDS at CD4+ < 200
What are some symptoms of HIV?
Fever, rash, vomiting, weight loss, mouth sores, hepatosplenomegaly
What happens as CD4+ count falls?
Number of infections can occur, getting worse as CD4+ count falls further
Give some examples of infections that can occur at low CD4+ counts:
TB, PCP, toxoplasmosis, CMV and lymphoma
How is HIV transmitted?
Sexual contact
Sharing injecting equipment
Vertical transmission
Medical procedures
What factors affect HIV transmission?
Type of exposure Viral load Other STIs Condom use Breaks in skin
How does HIV affect life expectancy?
No effect if detected and treated early
What diagnostic tests can be used if HIV is suspected?
Antigen-antibody test
Rapid test - finger prick or saliva (false positive)
Who is tested for HIV?
If rate is > 2/1000, everyone
If have serious infection/condition
What is the treatment for HIV?
3 antivirals:
2 nucleotide RT inhibitors plus 1 of: NNRTI, protease inhibitor, intergrase inhibitor or CCR5 inhibitor
Why are 3 antivirals used?
Stops virus developing resistance
What type of virus is Hep B?
Double stranded DNA with RT
How is Hep B transmitted?
Vertical transmission
IV drug use
Sex
Needlestick injuries
What are the symptoms of Hep B infection?
Jaundice, fatigue, anorexia and abdominal pain
What is the incubation period for Hep B?
6 weeks - 6 months
Describe the serology of Hep B (antigen and antibody appearance):
- Surface antigen first
- Followed by e-antigen - Highly infectious
- Core antibody (IgM)
- Followed by e-antibody - disappearance of e-antigen + infectivity
- Surface antibody - clearance of virus
- Core antibody (IgG) - Persists for life
How is chronic Hep B defined?
Persistence of surface antigen (HBsAg) after 6 months
What can chronic Hep B infection lead to?
25% - liver cirrhosis
5% - hepatocellular carcinoma
