L3 Flashcards
Hepatitis viruses target
liver
Hep Primarily infect and replicate in
hepatocytes
Hep damage
Liver damage from virus and host response
Hep Some cause
acute infections, some cause chronic infections
Hep A
Picornaviridae
(+)ssRNA
Nonenveloped
Hep b
Hepadnaviridae
Circular dsDNA
Enveloped
Hep C
Flaviviridae
(+)ssRNA
Enveloped
Hepatitis delta
(-)ssRNA
Enveloped
Deltaviridae
Hepatitis E
Calciviridae
(+)ssRNA
Nonenveloped
Hep prevelence
Prevalence
HDV & HEV are very rare in the US
Hepatitis B Virus
Hepadnaviridae
Hep B genome
dsDNA
Smallest genome of the human viruses
Hep b virion
Virion: enveloped
Hepatitis B Virus - Cannot be grown in
cell culture
Hepatitis B Virus Genome has
RNA intermediate
Hepatitis B Virus cccDNA is
template for transcription
Hepatitis B Virus Requires
liver specific transcription factors
Hepatitis B Virus Produce many
empty particles (HBsAy); present in infected people
Hepatitis B Virus infection
sexual & drug use
Hep b Incubation period
(30-180 days)
Hep b Symptom onset
General malaise, anorexia, vomiting, fatigue, cough, serum-like sickness
Jaundice, elevated alanine transaminase (ALT) levels
Hep b Recovery, approximately
3-4 months after onset of jaundice
Hepatitis B Virus
Chronic disease occurs in 5% of cases
Presence of HBsAg in blood for >6 mths confirms chronic infection
Marked by poor IgG response
Hep b Sporadic episodes of
hepatitis
Hep b Cirrhosis of the
liver
Hep b Increased risk for
hepatocellular carcinoma (HCC) HBV X gene/protein has tumorigenic potential
Hepatitis B Virus Vaccination
Available, first recombinant vaccine approved for use in humans
Requires multiple inoculations
Not effective against chronic infection
Hep b Treatment for chronic cases
Interferon-α therapy
Nucleoside analogs: adefovir, lamivudine, tenofovir
Hepatitis D Virus
Subviral agent
Rare in human viruses
Only other example is adeno-associated virus (AAV) which requires adenovirus infection
Hep D Requires
active HBV infection
Hep D RNA genome encodes a
single protein
Hepatitis C Virus
Flaviviridae
Hep C genome
: (+)ssRNA
Hep C Virion:
enveloped
Hep C Proteins:
E1&E2: attachment and entry
C: core
Various non-structural
Hepatitis C Virus Genome passed
into cytoplasm
Hep c Genome template for
translation
Missing cap, ribosomes recognize Internal Ribosome Entry Site (IRES)
Hepatitis C Virus Typically
milder signs and symptoms than observed for HBV
Hep c Chronic infections are
much more common, approximately 80% of infections
Hep c Extrahepatic disease
Mixed cryoglobulinemia – Antibody and virus complexes deposit in other tissues (e.g., kidneys) eliciting an immune response and subsequent tissue damage
Hep C treatment
Treatment – New product, ZEPATIER, on market to treat some genotypes. No vaccine available
Hepatitis A Virus infection
Infection – ingestion of fecally contaminated food or water
Absorbed through intestine and moves to liver via portal system
Hep a incubation
Incubation: 15-40 days
Hep A symptoms
Consistent with hepatitis infection: Maliase, anorexia, vomiting jaundice
More severe in adults than in children
Resolves approximately 8 weeks post infection
Prevention Hep A
Vaccine available
– Havrix, Vaqta killed/inactivated vaccine
Hepatitis E Virus caus3es
Causes foodborne and waterborne hepatitis
Hep E virus Disease is very similar to that caused by
HAV; distinguished by serology
Hep E Infection can be life threatening for
pregnant women
Hep E no prevention
available