Yoshimura: Hepatitis Viruses Flashcards
Hepatitis
Definition:
Main clinical features (4)
Hepatitis: inflammation and damage of the liver
Main clinical features: o Liver enlargement o Jaundice o Abdominal pain o Fever
Hepatitis
Other symptoms:
Can be caused by:
Other symptoms: lassitude (diminished energy), anorexia, weakness, N/V, chills and dark urine
Can be caused by: bacteria, protozoa, drugs, toxins and viruses (most important cause)
Hepatitis can assume two different phases:
Hepatitis can assume two different phases: acute and chronic.
Acute hepatitis produces:
How long does chronic phase last? Can result in?
Acute hepatitis produces temporary symptoms but depending on the virus can lead to chronic hepatitis.
Chronic phase lasts over a long period of time and can result in liver tumors (hepatomas).
What is the only hepadnavirus to infect humans?
What does HDV require to replicate?
HBV: only hepadnavirus to infect humans
HDV: viroid or satellite virus that requires HBV to replicate
Hep A
Family Genus Virion Envelope Genome Transmission Prevalence Fulminant Disease Chronic Disease Oncogenic
Hep A
Picornaviridae* Heparnavirus Icosahedral No ssRNA Fecal-oral High Rare Never No
Hep B
Family Genus Virion Envelope Genome Transmission Prevalence Fulminant Disease Chronic Disease Oncogenic
Hep B
Hepadnaviridae* Orthohepadnavirus Spherical Yes dsDNA Parenteral High Rare Often Yes
Hep C
Family Genus Virion Envelope Genome Transmission Prevalence Fulminant Disease Chronic Disease Oncogenic
Hep C
Flaviviridae* (Family include yellow fever virus) Hep-c-virus Spherical Yes ssRNA Parenteral Moderate Rare Often Yes
Hep D
Family Genus Virion Envelope Genome Transmission Prevalence Fulminant Disease Chronic Disease Oncogenic
Hep D
Unclassified Deltavirus Spherical Yes ssRNA Parenteral Low, regional Frequent Often ?
Hep E
Family Genus Virion Envelope Genome Transmission Prevalence Fulminant Disease Chronic Disease Oncogenic
Hep E
Hepevirus Hepevirus Icosahedral No ssRNA Fecal-oral Regional In pregnancy Never No
Hep F/G
Family Genus Virion Envelope Genome Transmission Prevalence Fulminant Disease Chronic Disease Oncogenic
Hep F/G
Flaviviridae ? ? ? ? ? ? ? ? ?
Other Viruses Causing Sporadic Hepatitis (6):
o EBV o CMV o HSV o Yellow fever virus o Rubella virus o Enteroviruses
Cell Tropism Accounts for Similar Symptoms
What is cell/tissue tropism dependent upon?
Many symptoms of acute hepatitis due to:
Cell/tissue tropism of a virus dependent on cellular receptors that can bind viral surface proteins
Many symptoms of acute hepatitis due to the damage/cytolysis of liver cells (hepatocytes)
Cell Tropism Accounts for Similar Symptoms
Damage to Hepatocytes Can Occur Two Ways:
Examples:
Damage to Hepatocytes Can Occur Two Ways:
Direct: cytolytic effect by virus (ie. HCV replication is cytopathic)
Indirect: immune response to infection (ie. chronic disease caused by HBV result of immune response of cytotoxic T cells)
Cell Tropism Accounts for Similar Symptoms
Other cell types can also be infected:
Where does HBV replicate? (5)
What can be lymphotrophic?
Other cell types can also be infected:
o HBV replicates in spleen, gonads, kidneys, LNs and blood mononuclear cells
o HCV may also be lymphotropic (infects lymphocytes)
Acute and Chronic Infections
Acute Infections:
What hepatitis viruses can cause acute hepatitis?
In what cases can primary infection may be asymptomatic? (2)
Acute and Chronic Infections:
Acute Infections: all hepatitis viruses can cause acute hepatitis to varying degrees
In some cases, primary infection may be asymptomatic: HBV and HAV
Acute and Chronic Infections
Chronic Infections:
For what viruses can primary infection cause chronic infection?
Chronic Infections: HBV, HCV and HDV primary infections can lead to a state of persistent/chronic infection.
Hepatic Cellular Carcinoma (HCC)
Definition:
Common with which hepatitis viruses?
Progression:
Hepatic Cellular Carcinoma (HCC): a common sequelae of chronic infection with HBV, HCV and HDV
Basics: gradual progression to cirrhosis and then to HCC (takes 25-50 years after primary infection)
Hepatic Cellular Carcinoma (HCC)
Prevalence:
Causes:
Prevalence: accounts for 90% of primary malignant tumors of the liver (but fairly uncommon in the US and other developed countries)
Causes: constant inflammation and stimulation of cellular replacement induces multiple mutations in hepatocytes, eventually leading to tumor formation.
HEPATITIS B VIRUS (HBV)
Pathogenesis
Transmission:
Transmission: primary infection due to sexual contact with infected host or from parenteral exposure to virus-containing blood/blood products
HEPATITIS B VIRUS (HBV)
Pathogenesis
Degrees of liver injury:
Incubation period:
What happens to the majority?
Primary Infection:
Asymptomatic, OR
Varying degrees of acute liver injury (acute hepatitis)
Incubation Period: 45-180 days
Vast majority resolve the primary infection: however, ~5% will go on to a persistent infection characterized by active viral replication in hepatocytes and varying degrees of viremia
HEPATITIS B VIRUS (HBV)
Pathogenesis
Chronic/Persistent Infection
Degrees of chronic liver injury:
What can be fatal?
What are those who live with symptomatic HBV at risk for developing?
Many are asymptomatic carriers (major reservoirs for spread of infection)
Others have varying grades of chronic liver injury and inflammation
- Severe chronic hepatitis can be fatal (5-year survival rates only ~50%)
- Others who live longer with symptomatic HBV at risk for developing HCC.
HEPATITIS B VIRUS (HBV)
Structure
HBV Particle Morphology: virions consist of multiple types of particles: (3)
Fully mature and infectious virions (Dane particle): only ones that contain genomic DNA
20nm spheres: usually the predominant form (up to 1 million times more than Dane particles); do not contain any nucleic acid, and are not infectious
Filamentous particles (20nm diameter): variable length, do not contain any nucleic acid, and are not infectious
HEPATITIS B VIRUS (HBV)
What is the only form with genomic DNA?
What is the predominant form?
Dane particle
20nm spheres
