Flashcards in Blood bourne virues (BBV) Deck (29)
What is a BBV?
A virus that has a viraemic phase that may be self limited (acute) or persistent (chronic)
They are enveloped and easily inactivated
Which three BBV are of main concern?
Hep B, Hep C, HIV
How are BBV's transmitted?
By blood and bodily fluids
Via mucus membranes or percutaneous
Where is Hep B prevalent?
Asia, Sub Saharan Africa
700,000 deaths /yr
How do we define acute and chronic Hep B?
Acute - most adults will overcome
Chronic - >6 months, may see chronic liver disease
What is the incubation period for Hep B?
60 - 90 days
What causes mortality in Hep B?
Hep B accounts for :
30% Liver cirrhosis
53% Hepatocellular cancer (HCC)
How do we diagnose Hep B?
Hep B surface antigen +ve = means currently infected
Hep B surface antibody +ve = means recovered
What is the management for acute Hep B?
No antivirals given
Counseling regarding transmission
Screen for other BBV and trace contacts
How do we manage chronic Hep B?
Give antiviral therapy - nucleoside analogues
How do we prevent transmission of Heb B?
Screening - especially pregnant and at risk groups
What is Hep C?
+ve SS RNA, enveloped
Many different genotypes distributed geographically
Name 2 high risk areas?
Egypt and Bristol
What is the progression of Hep C?
Acute infection (only 20% show symptoms)
Chronic infection (extrahepatic manifestations)
Chronic active Hep C
Cirrhosis ( can get HCC)
What causes burden in Hep C?
HCV accounts for :
27% liver cirrhosis
How do we manage acute Hep C?
Allow time for recovery
Treatment very effective
How do we manage chronic Hep C?
Asses liver function
Fibroscan ( increased stiffness = increased viral load)
Immunise against HAV and HBV
Antiviral therapy to clear virus and prevent progression
How can we prevent Hep C?
What is HIV?
retrovirus, enveloped ds RNA genome
Integrate into host cell chromosomes and can run off copies of virus regularly
What is the HIV related to?
HIV 1 - chimp virus
HIV 2 - sooty mangabey
How did the human HIV epidemic occur?
Result of exposure to blood during animal butchering and spread by urbanisation and travel
What population of people have the highest prevalence of HIV?
Gay men (MSM - men who sex with men)
What is vertical transmission?
HIV spread from mother to child
How do we diagnose HIV?
Test risk groups
What does the HIV virus do?
Attacks lymphocytes and constantly mutates
What are the 4 main oral signs of HIV?
Rash - non specific, often with flu 2 - 6 weeks after infection
Karposi's Sarcoma - raised purple lesions, linked to HHV8
Oral hairy leukoplakia - white plaques along lateral tongue borders. Link to EBV
How do we manage HIV?
Antiretroviral therapy (based on CD4 count and viral load)
There are drugs for all stages of the virus
What is combination therapy?
HAART - highly active anti-retroviral therapy
+vs: More potent, less drug resistance
-ves: More side effects