Chronic Viral Infections Flashcards
What are the major bloodborne viruses in context of clinical occupational exposure?
HIV
HepB V
HepC V
What are the types of hepatitis viruses?
A, B, C, D, E
How are hep B, C, and D transmitted? What else do they have in common?
Through needles and intercourse. They are all enveloped viruses
How are hep A and E transmitted?
They are transmitted via faecal-oral route and don’t have envelopes
What family is hepB a part of?
Hepadnaviridae
How is hep B transmitted?
Survives on various surfaces and is resistant to disinfectants. It is transmitted via blood-borne transmission. (Needle stick, IV drug injection, organ transplant, blood product transfusion, sexual and vertical transmission)
What does HBV do?
HBV infection accounts for ~50% of cirrhosis, end-stage liver disease and hepatocellular carnicoma.
Where is HBV commonly seen?
In areas of high endemicity, children get it from their mothers at birth.
Which body fluids are most high in concentration of HBV and which are lowest?
Highest: Blood, serum, wound exudates
Moderate: Semen, vaginal fluid, saliva
Low: Urine, faeces, sweat, tears, breast milk
What are the symptoms of HBV infection?
Most infections are asymptomatic but age of infection determines symptom likelihood.
Later acquisition leads to symptomatic infection (fever, abdominal pain, jaundice)
What percentage of 1 - 5 year olds infected with HBV develop symptoms?
5 - 10%
What percentage of adolscents and adults with HBV develop symptoms?
33 - 50%
Why are younger individuals more prone to HBV infection?
More developed immune system in adults
Who should be screened for hepB infections?
Patients with abnormal ALT (abnormal liver function)
Patients engaging in high-risk sexual behaviour
Injection drug users
People from areas of high endemicity
Immunocompromised patients
Dialysis patients
Transplant recipients
Sexual partners of known HBV carriers
Occupational exposure
Pregnant women
Indiviuals infected with HCV or HIV
What are the types of chronic Hep B disease?
Chronic persistent Hepatitis (asymptomatic)
Chronic active hepatitis (symptomatic exacerbations of hepatitis)
Cirrhosis of liver
Hepatocellular Carcinoma
Why is liver damage a consequence of some HBV infections?
Due to HBV-specific CD8+ T cell response
What percentage of people with chronic HBV infection develop cirrhosis?
30% approx and of these people 6% develop liver cancer and 23% liver failure within 5 years
What percentage of people with HBV develop liver cancer?
5 - 10%
What percentage of people with HBV develop Liver failure?
23%
Who most commonly get chronic HBV?
– Injecting drug users
– Men who have sex with men
– Correctional facility inmates
– Immigrants from endemic regions
– Aboriginal and Torres Strait Islander
peoples
What are the subtypes of HBV and can they all be prevented by a single vaccine?
HBV/A - H
Yes they are all prevented by the same vaccine
What is the difference between chronic and acute HBV infection in terms of antibody titre?
In acute infection
What serological tests are used for HBV?
HBsAg (If positive indicates infection and if it lasts for more than 6 months the infection is considered chronic)
Anti-HBs (anti HBV surface antigen antibodies indicates recovery and/or immunity to HBV)
HBeAg (Active HBV protein which indicates replication)
Anti-HBe (antibody to anti-HBe indicates recovery)
Anti-HBc (Ab)
How do nucleosides inhibit HBV from pathogenicity?
They inhibit reproduction.
