viral hepatitis part 1 W5 Flashcards
viral hepatitis types?
Hepatitis A/B/C/D/E
Hepatitis non-A/E
what do viruses need to replicate
require host cells and its cellular biochemical machinery to replicate
what do viruses consist of
DNA/RNA enclosed in a protein coat (nucleocapsid) and sometimes a host cell derived envelope
how do viruses attach to host cells
viruses attach to host cell using receptor-binding proteins targeting host cell surface molecules that also serve as virus-specific receptors
clinical symptoms of hepatitis?
jaundice
dark urine
clay-coloured stool
nausea and vomiting
loss of appetite
fever
abdominal pain
weakness
biochemical blood tests for hepatitis?
liver enzymes (ALT, AST, ALP, GGT)
other liver proteins (albumin, prothrombin)
bilirubin (indirect, direct)
serological and molecular tests for viral hepatitis?
enzymes immunosorbent assays (EIA)
molecular assays
serological and molecular tests for viral hepatitis - enzyme immunosorbent assays?
viral antigen
anti-viral antibody
serological and molecular tests for viral hepatitis - molecular assays?
PCR (viral load)
sequencing (genotype, antiviral resistance)
transmission of hepatitis?
B/C/D - transmitted parentally
A/E - transmitted faecal-orally
parenteral transmission meaning?
transmitted outside of GI tract (eg sexual contact and blood)
acute/chronic hepatitis types?
B/C/D - chronic
A/C/E - acute
who can hep D infect
only those who are already hep B positive
which types of hepatitis are more stable and why
types transmitted faecal-orally, as must survive for a longer time outside the body
hepatitis A - family?
picornavirus (same as viruses causing meningitis, encephalitis)
hepatitis A - incubation time?
10-50 days
who does hepatitis A mainly affect?
children and young adults
hepatitis A - seasonality?
no seasonality
hepatitis A - onset, resolution, fatality?
onset = abrupt with pyrexia
resolves spontaneously followed by life long immunity
fatality rate <0.5%
hepatitis A - treatment?
supportive
hepatitis A - test results
dramatic increase in liver enzymes
hepatitis A - vaccine?
inactivated virus vaccine and immunoglobulin available
HAV transmission?
transmitted via stool, contaminates water, infecting eg shellfish and vegetables
HAV diagnosis?
diagnosed with antibodies in blood
IgM and IgG antibodies
HAV outcome - children?
subclinical infection: 80-90%
icteric disease (jaundice): 5-20%
complete recovery: >98%
no chronic disease
fatality rate: 0.1%
HAV outcome - adults?
subclinical infection: 10-25%
icteric disease: 75-90%
complete recovery: >98%
no chronic disease
fatality rate: 0.3-2.1%
HBV - family and structure?
enveloped partially dsDNA hepadnavirus
HBV incubation time?
40-180 days
HBV mainly affects?
babies, young adults
HBV seasonality?
no seasonality
HBV onset?
insidious, sometimes apyrexia
HBV outcome
remains in hepatocytes for life, may re-activate under immunosuppression
chronic infection develops in 5-10% of adults, associated with hepatocellular cancer
HBV fatality rate?
up to 2% in icteric cases
HBV vaccine?
recombinant HBV surface antigen vaccine and immunoglobulin avaliable
HBV treatment?
interferon alpha or antivirals
HBV transmission?
parenteral, vertical, sexual
hepatitis B antigens?
surface antigen (envelope - active infection)
core antigen (nucleocapsid) - antibodies indicate recent infection)
E antigen (nucleocapsid) - active infection
HBV prevalence in europe/north america/australia?
HBsAg 0.2-0.5%
Anti-HBs 4-6%
neonatal infection rare
childhood infection rate
HBV prevalence in eastern europe, Mediterranean, former USSR, central and south america, south-west asia?
HBsAg 2-7%
Anti-HBs 20-55%
neonatal infection frequent
childhood infection frequent
HBV prevalence in south-east asia, parts of china, sub-saharan africa?
HBsAg 8-20%
anti-HBs 70-95%
neonatal infection very frequent
childhood infection very frequent
HBV infection outcomes in different age groups?
newborns have severe infections and high chances of chronic infections compared to older children and adults
