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172 SEcTioN ii Microbiology ` microbiology—Virology Microbiology ` microbiology—Virology
Hepatitis Signs and symptoms of all hepatitis viruses: episodes of fever, jaundice, ALT and AST. Naked viruses (HAV
viruses and HEV) lack an envelope and are not destroyed by the gut: the vowels hit your bowels.
HBV DNA polymerase has DNA- and RNA-dependent activities. Upon entry into nucleus, the polymerase
completes the partial dsDNA. Host RNA polymerase transcribes mRNA from viral DNA to make viral
proteins. The DNA polymerase then reverse transcribes viral RNA to DNA, which is the genome of the
progeny virus.
HCV lacks 3′-5′ exonuclease activity no proofreading ability antigenic variation of HCV envelope
proteins. Host antibody production lags behind production of new mutant strains of HCV.
Virus HAV HBV HCV HDV HEV
Family RNA picornavirus DNA hepadnavirus RNA flavivirus RNA deltavirus RNA hepevirus
traNsmissioN Fecal-oral (shellfish, Parenteral (Blood), Primarily blood Parenteral, sexual, Fecal-oral,
travelers, day care) sexual (Baby- (IVDU, post- perinatal especially
making), perinatal transfusion) waterborne
(Birthing)
iNcUbatioN Short (weeks) Long (months) Long Superinfection Short
(HDV after
HBV) = short
Coinfection (HDV
with HBV) = long
cliNical coUrse Acute and self Initially like serum May progress to Similar to HBV Fulminant hepatitis
limiting (adults), sickness (fever, Cirrhosis or in Expectant
Asymptomatic arthralgias, rash); Carcinoma (pregnant) women
(children) may progress to
carcinoma
ProgNosis Good Adults mostly Majority develop Superinfection High mortality in
full resolution; stable, Chronic worse prognosis pregnant women
neonates worse hepatitis C
prognosis
Hcc risK No Yes Yes Yes No
liVer bioPsy Hepatocyte Granular Lymphoid Similar to HBV Patchy necrosis
swelling, eosinophilic aggregates with
monocyte “ground glass” focal areas of
infiltration, appearance; macrovesicular
Councilman cytotoxic T cells steatosis
bodies mediate damage
Notes No carrier state Carrier state Carrier state very Defective virus, Enteric, Epidemic
common common Depends on (eg, in parts of
HBV HBsAg coat Asia, Africa,
for entry into Middle East), no
hepatocytes carrier state
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