W2: Blood Borne Viral Infections

Question 1

What are common BBV?

Answer 1

Question 2

HIV

Answer 2

infection flue like

AIDS = as a result of HIV infection

Question 3

Hep B

Answer 3

Question 4

Hep C

Answer 4

Hepatitis A is spread through the stool of an infected person, hepatitis B is spread through bodily fluids, and hepatitis C is spread through blood. It’s important to remember that you can’t get hepatitis just by touching someone who is infected.

Question 5

How do viruses replicate/ we contract it?

Answer 5

Question 6

Methods to reduce incidence of transmission

Question 7

What is general Management strategy for needle stick injury?

Answer 7

Question 8

What happens if dental practitioners/ HCW get positive infection/ Ag +?

Answer 8

1. cannot practice exposure form procedures

• In florida DP, orthopeadic surgeon did infect, hasn’ t happened in Aus yet.
  -HCV infection high in health international, mainly nurses

Question 9

Exposure prone procedures

Answer 9

mouth, blood infected come contact to tissue. Sharps involved, sharp tissue in open body cavity

Question 10

HIV

Answer 10

HIV takes years bc affects CD4 T cells

Question 11

How is HIV detected?

Answer 11

saliva, blood

Question 12

Types of HIV

Answer 12

2 types
most likely in western= HIV1 - spreads faster
-

HIV2 slightly less infectious, mainly found in West Africa (huge problem)

Question 13

Prevalence of HIV in Australia

Answer 13

dic. 1959 in Congo
-2013: HIV + 35 mill. with 2.1 m infections/year. mainly west Africa/developing
- 2013: 25K in Aus, infection rate slowing down by 40% in last decade due to presence of antiretroviral Tx (decrease AIDS and viral genome)

Prophylaxis

Question 14

HIV replication

Answer 14

It’s a ‘retro virus’= can stay for long infection.

can integrate its own DNA to host DNA (inside DNA of CD4 T cell)

1. binds CD4 on T cell with CCR5 co receptor (kinokine receptor)
2. fuse with T cell
3. release proteins like rna to replicate and reverse transcript and integrate into host genome

summary
enters by RNA strain, reverse transcript to DNA, integrate to host, host pumps out ‘viral’ genome/ proteins as it would it’s own= RUNNING OFF THE SCRIPT

new protein- > virion

replication destroys CD4 cell

enough virus budding leads to

Question 15

Diff transmission of HIV 1 and 2

Answer 15

HIV 2 can infect more cells bc it has an extra coreceptor, compared to HIV 1

Question 16

HIV pathogenesis is characterised by

Tx is characterised by?

Answer 16

rapid decrease of CDT4 cells

as a result of

increase HIV rna in blood, increase slowly until you get ‘aquirement’ of AIDS

In tx.
HIV is unable to be detected and CD4T levels remain OK, prevents onset of aids

Question 17

What is Hep? mains symptom?

Answer 17

inflammation liver

main symptom: yellow/jaundice bc liver can’t detox, build up of toxins

Question 18

Hep B

Answer 18

virus attacks liver

acute and chronic disease

Question 19

Is there a vacc for Hep B

Answer 19

Yes. safe. Hep B more controversial bc ppl say “i dont have Ab against Hep B”

use to be 2 now its min 3 times.

Question 20

Prev of Hep B

Answer 20

~300m infected with chronic Hep B, 1.5m new each year (WHO, 2019), half of chronic are undioagnosed (they don’t know they have it)
~1m deaths assoc with HepB mainly due to liver cancer and cirrhosis (liver shuts down bc of death of liver bc cannot filter anything)

Question 21

Hep B virus itself

Answer 21

small DNA virus with wierd ft.

has diff genome/replication process to other DNA virus

• has RNA intermediate that mix into genome
• 8 diff types unlike HIV has 2, this one has 8
• good replicator
• targets liver cells, causing disease
• super hardy. an survive 1 wk outside body thats why steri needs to be done
  -transmission: fluid- dev. country = mother to child (prom in carribean?)
• acquired during early childhood mainly
• found in saliva but no doc infection

Question 22

Incubation period for Hep B

Answer 22

75 days until you see symptoms. up to 6 months.

pretty decent time for virus. compared to COVID you get sick in 2 days

Question 23

Replication process of Hep B

Answer 23

1. virus bind to receptor of cell surface
2. in virion, relax circular DNA genome, unpackage, DNA rls into nucleus of cell, becoming covalent closed DNA (diff shape)
3. transcribed
4. translation

surface ag
- traffic to surface of cell, sub virus particles
- relaxed circular DNA, goes back to cont. cycle
- expression of ECspace= virion that can infect

Question 24

Hep C

Answer 24

same as Hep B, but virus is Hep C

similar, can cause acute + chronic hepatitis

less disrtibuted
- 58m have chronic hep C infection, 1.5 m every year.
- 300K ppl died of Hc in 2019 bc of cirrhosis and liver cancer

Question 25

What is Tx for Hep C?

Answer 25

Antiviral meds shown to cure 95% of Hc virus. but con is its expensive, only like Aus, UK and US has ready access to it. In Aust. ppl are getting cured but there isnt huge prev here.

Question 26

What does Hep C virus look like?

Answer 26

- small , enveloped, +ss RNA - like HIV also positive but this one is NOT a retrovirus - comes from Flaviviridae fams, genus is diff (this Virus i s not mosquito born, just in humans)

Question 27

Most simple rep cycle V? What is process?

Answer 27

Hep C - viral att to cell receptors (diff virus use diff cell receptors) - V engulfed into cell, enters in cell to fuse with endosomal mem - release ss RNA genome which is already POSITIVE (positive= messenger, stuff that cellular translation machinary can read str8 away) - polyprotein produced- one whole genome prod. at Endoret in replication complexes (RCs) - cleavage of polyprotein -viral assembly - traffic out transgolgi network - viral released in extracellular space - back in blood 7

Question 28

What is risk of healthcare worker (HW)?

Answer 28

infection risk after being exposed to pt with HBV, HIV - HBV= most infections, esp needlestick injury. HBsAg= surface Ag HBeAg= core Ag (mainly used for dx in aust)

Question 29

Serology will find a chance 40-60% of HBV infection after needle injury by detecting presence of what?

Answer 29

HBsAg= surface Ag HBeAg= core Ag (mainly used for dx in aust)

Question 30

If pt is HCV positive what is chance of being positive for HCV?

Answer 30

1.8-7% HIV is lower (0.3%)- good bc HIV is gnarly awful.

Question 31

HCW needed to tested for viruses when?

Answer 31

every 3 years

Question 32

What levels are considered infectious in blood?

Answer 32

HIV >200 viral copies/mL blood (NO exposure prone procedures HCV RNA + HBV DNA >200 units

Question 33

What is relative risks of viruses

Answer 33

HBV more infections HIV tho scariest is least infectious

Question 34

Needle stick injuries

Answer 34

burs, syringe, sharps. injury with blood. When you put needle down, that's when you become unconscious of sharp injury. HAVE to involve small amt of blood, so have to break into skin - oral surgeons: more likely in fracture reductions and wire ligatures - also can splashing of mucous membranes with blood

Question 35

MEthods to prevent needle injuries

Answer 35

- isolate or cover sharps - one hand technique so you don't stab other hand - instruments rather than fingers - sharps bin -PPE

Question 36

Mx of needle injury

Answer 36

- wound mx- wash wound with soap - let it bleed to clear wound site out - report injury - assess infection risks, what was exposure, how much blood was there - get tests DP and pt. - are they immuno comp or immuno suppressed - baseline status= monitered for period bc virus takes long - PEProphylaxis= antiretroviral, post exposure and cont. monitor both person wks- mnths for signs and symptoms of viral infection

Question 37

Process of infected DP

Answer 37

1positive - NO work - Anti virals for HIV or whichever virus - until numbers under thresholds (no work) - can still perform when negative, so

Question 38

Infected DP

Answer 38

- don't have to report to AHPRA or work, - cont to do job provided infection is in control but like insurance could ban you if you dont be honest

Question 39

does 3 dose ensure immunity?

Answer 39

depends to ppl, some may need boosters more. lifespan of protection of vaccine= 15-30yrs...