Mhr Topic 27: Hepatitis Viruses

Front 1

Hepatitis A (name, genome, envelope, transmission, chronicity)

Back 1

1) Picornavirus
2) SS+ polarity RNA
3) No envelope
4) Enteric, via oral fecal
5) Not Chronic

Front 2

Hepatitis B (name, genome, envelope, transmission, chronicity)

Back 2

1) Hepadenavirus
2) Partially DS DNA
3) Enveloped
4) Parenternal via blood/sex contact
5) Chronic

Front 3

Hepatitis C (name, genome, envelope, transmission, chronicity)

Back 3

1) Flavivirus
2) SS+ polatiry RNA
3) Enveloped
4) Parenternal via blood/sex contact
5) Chronic

Front 4

Hepatitis D (name, genome, envelope, transmission, chronicity)

Back 4

1) Viroid
2) Circular SS- RNA
3) Enveloped
4) Parenternal via blood/sex contact
5) Chronic

Front 5

Hepatitis E (name, genome, envelope, transmission, chronicity)

Back 5

1) Hepevirus
2) SS+ RNA
3) No envelope
4) Enteric via oral fecal
5) Not chronic

Front 6

Hepatitis A (Initial infection and replication)

Back 6

1) Initially replicates in intestinal epithelium then infects liver (common in restaurant contamination)
2) Cytoplasmic RNA-RNA replication by viraly encoded polymerase. Produces a large polytprotein which is cleaved. Virions assemble in in cytoplasm and are released by cytolysis.

Front 7

Hepatitis A (Disease, incubation, duration)

Back 7

80% of infections asymptomatic. Almost all childhood asymptomatic.
Symptoms: Dark urine, pales feces, jaundice.
Incubation = 10-50 days. Duration = 2-4 weeks

Front 8

Hepatitis A Diagnosis

Back 8

Serology via detecting anti HAV IgM against marker.

Front 9

Hepatitis B (Initial infection and replication)

Back 9

1) Blood/sex contact in developed countries, vertical in non-developed.
2) Replicates via reverse transcription. HBV enters cell, releases DNA which goes to nucleus. Does NOT intergrate. mRNAs are transcribed and translated. mRNAs encode for an RNA genome to serve as a DNA template, i viral DNA pol, and proteins which form a cytoplasmic core. Reverse transcription occurs in cytoplasm in core. Some DNAs go back to nucleus to add more templates, some go to ER to be shipped outa cell. Viral factory, not cytolytic.

Front 10

Hepatitis B (Disease, incubation, duration)

Back 10

Pathology is primarily by immune system via cytotoxic T cells. Disease can be acute or chronic.
Acute: Most infections are subclinical. Symptoms similar to HAV: Dark urine, pales feces, jaundice. Incubation = 50-150 days, Duration = 2-3 months.
Chronic: 90% of neonates and 5% of adults become chronic. Variable ranging from asymptomatic for a long time to flareups of acute, to liver failure.
While DNA is not usually incorporated into host genome, can occasionally in chronic cases causing hepatocellular carcinoma.

Front 11

What is the serologic indicator for a chronic HBV infection?

Back 11

Continued presence of HBsAg for 6 months without detection of anti-HBs.

Front 12

Hepatitis D (Infection and replication)

Back 12

1) Perenternal. Absolutley dependent on co-infection w/ HBV.
2) Replicates via direct RNA-RNA in the nucleus. Both genomic and antigenomic RNAs are trimmed and circularized by ribozymes which exist within the RNAs. Encodes for 1 protein, delta antigen. Thats why needs HBV to provide surface glycoproteins to make envelope. Actual replication is HBV independent.

Front 13

Hepatitis D Disease

Back 13

Increases severity of HBV. Infection with HDV can trigger a chronic HBV carrier to become symptomatic. Can increase risk of carcenoma and establish chronic infections.

Front 14

Hepatitis D Diagnosis

Back 14

Anti delta antigen IgM

Front 15

Hepatitis C Infection and Replication

Back 15

1) Parenternal. Usually IV drugs, unsterilized equipment, and transfusions until the 90s. Not usually sex or vertical.
2) Cytosolic RNA-RNA replication. Virion internalized, releases genome, and translated via viral IRES. Produces a polyprotein which is cleaved host and viral proteases forming mature viral proteins. New particles are released from cell. Virion factory, not lytic.

Front 16

Hepatitis C Disease

Back 16

Incubation is 6-10 weeks. Disease is similar to B except is responsible for disproportionally large fraction of serious problems b/c of high rate of chronic infections (80%). A quarter of chronic people develop the bad chronic symptoms.

Front 17

Hepatitis C Diagnosis

Back 17

Serology via detection of anti HCV IgG. Howerer this creates a 5-6 week window between infection and detection b/c there is no IgM assay. Can also use RT-PCR but - samples can have low infectivity.
Hummoral immune system is slow and ineffective against HCV leading to low antibody titers that dont persist long after acute infection.

Front 18

Hepatitis E (Infection/replication)

Back 18

1) Enterically, fecal/oral
2) Cytoplasmic RNA-RNA replication

Front 19

Hepatitis E Disease

Back 19

Disease same as A. Infections usually asymptomatic. Incubation = 3-8 weeks.

Front 20

How is HBV treated?

Back 20

With neucleoside analogs and INF

Front 21

How is HCV treated?

Back 21

With INF