blood borne viruses Flashcards by Sana Rana

what is a blood borne disease

a disease that can be spread from contamination of blood and other bodily fluids

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give examples of blood borne diseases

hep B
hiv
viral haemorrhage fever

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deacribe viral hepatitis

liver inflammation due to a viral infection
can be acute or chronic
five hepatotophic viruses-ABCDE

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which other viruses can cause hepatitis

cytomegalovirus
epstein barr virus
flavivirus- yellow fever

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what is another name glandular fever

epstein barr virus

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what do we need to consider when taking the medical history

what type of hepatitis they had and whether they currently have it

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describe hepatitis A

passed via food and drink with infected faeces- not usually blood borne viruses

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how can we prevent hepatitis A spreading

good hand hygiene
water filtration
vaccines

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how do we diagnose hepatitis A

IgM antibodies in blood

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what is the treatment of hep a

rest and fluids

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describe hep B

super infectious- risk of 6-30% from infected needle stick injury depending on hep B status
vaccine- successful in 95%

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what is a notifiable disease

the doH will need to know about this

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what does hep b cause

acute and chronic inflammation

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where is hep b present

blood
semen
vaginal fluid
eg toothbrush sharing, razors

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how can hep b be transmitted

vertical- mother to child

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where does hep b replicate

in the liver cells and then cause damage to hepatocytes- this causes them to look slightly “blobby”

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how does hep b REPLICATE

PARARETROVITAL

enters via endocytosis into the hepatocyte
viral capsid is shed- and transferred to the cell nucleus
viral polymerase transforms the DNA into a double stranded 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

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why does the viral polymerase make the DNA circular

to make it more stable

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what does circular DNA contain

transcripts for 4 viral mRNAS

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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

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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

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what does it mean if your blood test comes out negative for HBSAg and AntiHBC negative

not currently infected

never infected

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what does it mean if your blood test comes outwit HBSAG +

currently infected

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what does it mean if your blood test comes outwit HBsAG -

AND AntiHBc +

not currently infected but has been before

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what does it mean if your blood test comes outwit HBeAg + and anti Hbe -

active viral replication

what does it mean if your blood test comes outwit HBSAG - | and anti HBE+

virus replication under immune control

what does it mean if your Anti HB less than 10ml/ml

not vaccinated/ineffective

what does it mean if your Anti HB 10-100ml/ml

partial vaccine response | consider repeating

what does it mean if your Anti HB greater than 100ml/ml

full vaccine response

what happens during hep b exposure

acute infection | acute hepatitis

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 ```

what can chronic hep B lead to

hepatocellular carcinoma

what is the treatment for hep B

most people spontaneously recover | immunocompromised might need antiviral or immune system modulators

what do we test for during pregnancy

antenatal testing | 80-90% mother to baby transmission

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

how can we prevent Hep B

safe sex immunisation PPE

describe Hepatitis C

single stranded RNA virus replicated in hepatocytes

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

what are the risks to get hep c

blood transfusion prior to 1987 unprotected sec vertical transmission from other to baby

what is the main symptom of hep c

fatigue

what is cirrhosis

liver cells start to die off and scarring starts to occur

how long can it take for hep c progression

20-30 years

why is there no vaccine for hep c

mutation occurs and highly variable structure

describe hep D

it is a sub viral satellite- only replicates in the presence of hep b

when does hep D replicate

only in the presence of hep B

what is hep d & E associated with

IV drug use

how does hep D enter the hepatocyte

due to the help of the Hep B surface antigen

what is the mortality rate when someone has hep B and Hep D

20% highest mortality rate

how is hep e transmitted

not a BBV faecal oral route domestic animals act like a reservoir

what can hep E lead to in immunocompromised patients

fibrosis and cirrhosis

describe hIV

it is a retrovirus | uses reverse transcriptase to make cDNA which can be integrated into the host cell

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

how is HIV transmitted

blood semen sexual transmission vertical transmission

how do we prevent the spread of HIV

``` safe sex safe injections antenatal treatment PPE conception no sharing razors ```

what is AIDS

if enough CD4 cells are depleted

how many CD4 do uninfected adults have

500-1600 cells per mm3

how can cd4 count vary

by exercise | sleep

what is a dangerous count of CD4 which can lead to progression of AIDS

less than 200

when is the viral load undetectable

40-75 copies within 1ml of blood

why are low loads good

reduce the transmission but does not eradicate

what are the symptoms of acute HIV

``` fatigue headache rash sore throat lymphadenopathy ```

what are chronic symptoms of HIV

``` fever WEIGHT LOSS lymphadenopathy same as acute besides fungal infections- candida bacterial-TB ```

describe prion disease

infectious agent made from proteins | affects the brain and neural tissue

what does prion disease affect

the brain and neural tissue

how does prion cause disease

it causes properly folded proteins to convert into the misfolded prion form

what is the the ultimate end of prions disease

tissue damage and death

what are prions resistant to

denaturation by chemical and physical agents making disposal and decontamination difficult cannot be autoclaved

describe prion affected tissued

microscopic holes giving a sponge appearance

describe CJD

Creutzfeldt- Jakob disease | leads to dementia, personality changes, hallucinations

what are the types of CJD

sporadic familial varient iatrogenic

describe sporadic CJD

no cause identified | accounts for 85%

what is variant CJD

caused by the consumption of food contaminated with prions which also cause bovine spongiform encephalopathy

describe iatrogenic CJD

contamination from an infected person- result of medical procedure

what is HTLV

human T lymphocytic virus

how many types of HTLV

4 types- type one is the most important

what is HTLV1 linked to

myelopathy | leukaemia

what is HTLV2 linked to

milder neurological conditions and infections

what are oncoviruses

can lead to cancer | blood borne and transmitted by body fluids

which virus can lead to cancer

``` HBV BCV BTLV HPV karposis sarcoma associated with herpesvirus MCV- merkel cell polyomavirus glandular fever ```

what is post exposure prophylaxes

available from a&e genitourinary ID unit provided with drug treatment to prevent infection

what should we help with IV drug users

need to help injectors switch oral substitution by smoking, snorting,swallowing

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 ```

blood borne viruses Flashcards

hepatitis CJD and HIV modes of transmission risks prevention relevance to dentistry