blood borne viruses Flashcards
hepatitis CJD and HIV modes of transmission risks prevention relevance to dentistry (98 cards)
1
Q
what is a blood borne disease
A
a disease that can be spread from contamination of blood and other bodily fluids
2
Q
give examples of blood borne diseases
A
hep B
hiv
viral haemorrhage fever
3
Q
how do we classify viruses
A
by the baltimore classification which involves I dsDNA virus II ssDNA virus III dsRNA IV + strand or sense ssRNA virus V- ssRNA VI ssRNA-RT viruses VIII dsDNA-RT
4
Q
deacribe viral hepatitis
A
liver inflammation due to a viral infection
can be acute or chronic
five hepatotophic viruses-ABCDE
5
Q
which other viruses can cause hepatitis
A
cytomegalovirus
epstein barr virus
flavivirus- yellow fever
6
Q
what is another name glandular fever
A
epstein barr virus
7
Q
what do we need to consider when taking the medical history
A
what type of hepatitis they had and whether they currently have it
8
Q
describe hepatitis A
A
passed via food and drink with infected faeces- not usually blood borne viruses
9
Q
how many cases of hep A are there a year
A
1.4 million cases every year
10
Q
how can we prevent hepatitis A spreading
A
good hand hygiene and water filtration and vaccines
11
Q
how many people in the developing world have hep A in the developing world
A
90% of children infected by the age of 10
12
Q
how do we diagnose hepatitis A
A
IgM antibodies in blood
13
Q
how many people are affected by symptomatic hep A a year
A
1.4 million
14
Q
how many deaths per year does symptomatic hep A result in
A
102000 deaths per year
15
Q
what is the treatment of hep a
A
rest and fluids
16
Q
describe hep B
A
super infectious- risk of 6-30% from infected needle stick injury depending on hep B status
vaccine- successful in 95%
17
Q
what is a notifiable disease
A
the doH will need to know about this
18
Q
what does hep b cause
A
acute and chronic inflammation
19
Q
where is hep b present
A
blood
semen
vaginal fluid
eg toothbrush sharing, razors
20
Q
how can hep b be transmitted
A
vertical- mother to child
21
Q
where does hep b replicate
A
in the liver cells and then cause damage to hepatocytes- this causes them to look slightly “blobby”
22
Q
how does hep b REPLICATE
A
PARARETROVITAL
- enters via endocytosis into the hepatocyte
- viral capsid is shed- and transferred to the cell nucleus
- viral polymerase transforms the DNA into the circular loop
- the mRNAS make new DNA and capsids which form new virons which can be released from the cell- and the hepatocyte dies when lysis occurs
23
Q
why does the viral polymerase make the DNA circular
A
to make it more stable
24
Q
what does circular DNA contain
A
transcripts for 4 viral mRNAS
25
what does a hep b capsid look like
outer membrane- contains HBsAg and HBeAG ( hepatitis B e antigen) and means people can spread the virus
the inner membrane has HBcAg
and DNA polymerase and the RNA on the inside
26
what do we test for in a positive test for Hep B
postive in hepatitis B surface antigen and HBeAg
| HBcAb- in previously exposed or currently exposed hep B
27
what does it mean if your blood test comes out negative for HBSAg and AntiHBC negative
not currently infected
| never infected
28
what does it mean if your blood test comes outwit HBSAG +
currently infected
29
what does it mean if your blood test comes outwit HBsAG -
| AND AntiHBc +
not currently infected but has been before
30
what does it mean if your blood test comes outwit HBeAg + and anti Hbe -
active viral replication
31
what does it mean if your blood test comes outwit HBSAG -
| and anti HBE+
virus replication under immune control
32
what does it mean if your Anti HB less than 10ml/ml
not vaccinated/ineffective
33
what does it mean if your Anti HB 10-100ml/ml
partial vaccine response
| consider repeating
34
what does it mean if your Anti HB greater than 100ml/ml
full vaccine response
35
what happens during hep b exposure
acute infection
| acute hepatitis
36
how many people suffer from symptoms:
30% symptoms
| 70% subclinical
37
out of the 100% that have Hep B how many are healthy carries
30%
38
out of the 100% that have Hep B how many are recovered and healthy
less than 2%
39
out of the 100% that have Hep B how many suffer from cirrhosis
12-20% which can lead to hepatocellular carcinoma
40
what are the symptoms of hep B
```
loss of appetite
cause
vomiting
body aches
mild fever
dark urine
pruritus- itching
liver failure may result in health
```
41
what can chronic hep B lead to
hepatocellular carcinoma
42
what is the treatment for hep B
most people spontaneously recover
| immunocompromised might need antiviral or immune system modulators
43
what do we test for during pregnancy
antenatal testing
| 80-90% mother to baby transmission
44
what do we deliver to the baby if the mother is +
antibodies
then 1st dose of vaccine in 12 hours post birth
vaccines at 1,2 and 12 months
45
how can we prevent Hep B
safe sex
immunisation
PPE
46
describe the hep B vaccine
derived in 1981
currently in recombinant from
boosters might be needed
47
describe Hepatitis C
single stranded RNA virus replicated in hepatocytes
48
how does hep C replicate
1. attaches to the hepatocyte by protein E and gets endocytose
2. incorporated into the DNA cell, shuts down normal cell function
3. capsid production and assembly
4. hepatocyte cell lysis leading to spread of hep c virus
49
what are the risks to get hep c
blood transfusion prior to 1987
unprotected sec
vertical transmission from other to baby
50
how much % of the world pop have hep c
3%
51
what is the main symptom of hep c
fatigue
52
what is cirrhosis
liver cells start to die off and scarring starts to occur
53
how long can it take for hep c progression
20-30 years
54
why is there no virus for hep c
mutation occurs and highly variable structure
55
describe hep D
it is a sub viral satellite- only replicates in the presence of hep b
56
when does hep D replicate
only in the presence of hep B
57
what is hep d & E associated with
IV drug use
58
how does hep D enter the hepatocyte
due to the help of the Hep B surface antigen
59
what is the mortality rate when someone has hep B and Hep D
20% highest mortality rate
60
how is hep e transmitted
not a BBV
faecal oral route
domestic animals act like a reservoir
61
what can hep E lead to in immunocompromised patients
fibrosis and cirrhosis
62
describe hIV
it is a retrovirus
| uses reverse transcriptase to make cDNA which can be integrated into the host cell
63
how does HIV replicate
1. binds to the host cell eg a T cell lymphocyte by the CD4 receptor
2. HIV releases reverse transcriptase to produce cDNA
3. viral dna enters the cell nucleus and enters the host dan
4. viral proteins are produced and are immature HIV
5. the virus buds from the host cell and viral proteases break down the proteins making a mature HIV
64
how is HIV transmitted
blood
semen
sexual transmission
vertical transmission
65
how do we prevent the spread of HIV
```
safe sex
safe injections
antenatal treatment
PEP
conception
no sharing razors
```
66
what is AIDS
if enough CD4 cells are depleted
67
how many CD4 do uninfected adults have
500-1600 cells per mm3
68
how can cd4 count vary
by exercise
| sleep
69
what is a dangerous count of CD4 which can lead to progression of AIDS
less than 200
70
when is the viral load undetectable
40-75 copies within 1ml of blood
71
why are low loads good
reduce the transmission but does not eradicate
72
what are the symptoms of acute HIV
```
fatigue
headache
rash
sore throat
lymohadenopathy
fatigue
```
73
what are chronic symptoms of HIV
```
fever
WEIGHT LOSS
lymphadenopathy
same as acute besides
fungal infections- candida
bacterial-TB
```
74
describe prion disease
infectious agent made from proteins
| affects the brain and neural tissue
75
what does prion disease affect
the brain and neural tissue
76
how does prion cause disease
it causes properly folded proteins to convert into the misfolded prion form
77
what is the the ultimate end of prions disease
tissue damage and death
78
what are prions resistant to
denaturation by chemical and physical agents making disposal and decontamination difficult
cannot be autoclaved
79
describe prion affected tissued
microscopic holes giving a sponge appearance
80
describe CJD
Creutzfeldt- Jakob disease
| leads to dementia, personality changes, hallucinations
81
what rate does CJD occur at
1 case/million per year
82
how many people in the UK are carries of CJD
1/2000
83
what are the types of CJD
sporadic
familial
varient
iatrogenic
84
describe sporadic CJD
no cause identified
| accounts for 85%
85
describe familial CJD
15% of cases
86
what is variant CJD
caused by the consumption of food contaminated with prions which also cause bovine spongiform encephalopathy
87
describe iatrogenic CJD
contamination from an infected person- result of medical procedure
88
when was mad cow disease first discovered
1986
89
when was the first case of vCJD found in humans
1996
90
what is HTLV
human T lymphocytic virus
91
how many types of HTLV
4 types- type one is the most important
92
what is HTLV1 linked to
myelopathy
| leukaemia
93
what is HTLV2 linked to
milder neurological conditions and infections
94
what are oncoviruses
can lead to cancer
| blood borne and transmitted by body fluids
95
which virus can lead to cancer
```
HBV
BCV
BTLV
HPV
karposis sarcoma associated with herpesvirus
MCV- merkel cell polyomavirus
glandular fever
```
96
what is post exposure prophylaxes
available from a&e
genitourinary
ID unit
provided with drug treatment to prevent infection
97
what should we help with IV drug users
need to help injectors switch
oral substitution
by smoking, snorting,swallowing
98
what advice should we give to Iv DRUG USE
```
use of sterile eq
where to get supplies
where to inject
how to
dealing with injection issues
```
