Blood bourne virues (BBV)

Question 1

What is a BBV?

Answer 1

A virus that has a viraemic phase that may be self limited (acute) or persistent (chronic)
They are enveloped and easily inactivated

Question 2

Which three BBV are of main concern?

Answer 2

Hep B, Hep C, HIV

Question 3

How are BBV’s transmitted?

Answer 3

By blood and bodily fluids

Via mucus membranes or percutaneous

Question 4

Where is Hep B prevalent?

Answer 4

Asia, Sub Saharan Africa

700,000 deaths /yr

Question 5

How do we define acute and chronic Hep B?

Answer 5

Acute - most adults will overcome

Chronic - >6 months, may see chronic liver disease

Question 6

What is the incubation period for Hep B?

Answer 6

60 - 90 days

Question 7

What causes mortality in Hep B?

Answer 7

Hep B accounts for :
30% Liver cirrhosis
53% Hepatocellular cancer (HCC)

Question 8

How do we diagnose Hep B?

Answer 8

Serological patterns:
Hep B surface antigen +ve = means currently infected
Hep B surface antibody +ve = means recovered

Question 9

What is the management for acute Hep B?

Answer 9

No antivirals given
Counseling regarding transmission
Screen for other BBV and trace contacts

Question 10

How do we manage chronic Hep B?

Answer 10

Give antiviral therapy - nucleoside analogues

Immuno-modulators

Question 11

How do we prevent transmission of Heb B?

Answer 11

Screening - especially pregnant and at risk groups

Vaccine

Question 12

What is Hep C?

Answer 12

+ve SS RNA, enveloped

Many different genotypes distributed geographically

Question 13

Name 2 high risk areas?

Answer 13

Egypt and Bristol

Question 14

What is the progression of Hep C?

Answer 14

Hep C
Acute infection (only 20% show symptoms)
Chronic infection (extrahepatic manifestations)
Chronic active Hep C
Cirrhosis ( can get HCC)

Question 15

What causes burden in Hep C?

Answer 15

HCV accounts for :
27% liver cirrhosis
25% HCC

Question 16

How do we manage acute Hep C?

Answer 16

Allow time for recovery

Treatment very effective

Question 17

How do we manage chronic Hep C?

Answer 17

Asses liver function
Fibroscan ( increased stiffness = increased viral load)
Immunise against HAV and HBV
Antiviral therapy to clear virus and prevent progression

Question 18

How can we prevent Hep C?

Answer 18

NO VACCINE

Question 19

What is HIV?

Answer 19

retrovirus, enveloped ds RNA genome

Integrate into host cell chromosomes and can run off copies of virus regularly

Question 20

What is the HIV related to?

Answer 20

HIV 1 - chimp virus

HIV 2 - sooty mangabey

Question 21

How did the human HIV epidemic occur?

Answer 21

Result of exposure to blood during animal butchering and spread by urbanisation and travel

Question 22

What population of people have the highest prevalence of HIV?

Answer 22

Gay men (MSM - men who sex with men)

Question 23

What is vertical transmission?

Answer 23

HIV spread from mother to child

Question 24

How do we diagnose HIV?

Answer 24

Sreening

Test risk groups

Question 25

What does the HIV virus do?

Answer 25

Attacks lymphocytes and constantly mutates

Question 26

What are the 4 main oral signs of HIV?

Answer 26

Rash - non specific, often with flu 2 - 6 weeks after infection
Oral candida
Karposi’s Sarcoma - raised purple lesions, linked to HHV8
Oral hairy leukoplakia - white plaques along lateral tongue borders. Link to EBV

Question 27

How do we manage HIV?

Answer 27

Counselling
Antiretroviral therapy (based on CD4 count and viral load)
There are drugs for all stages of the virus

Question 28

What is combination therapy?

Answer 28

HAART - highly active anti-retroviral therapy
+vs: More potent, less drug resistance
-ves: More side effects

Question 29

Out of Hep B, Hep C and HIV, which is the most risky for transmission?

Answer 29

HBV = 30-3%
HCV = 1-3%
HIV = 0.3%