Flashcards in Micro hepatitis viruses Deck (28):
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hepatitis A virology
picornavirus; ssRNA, naked icosahedral capside; environmentally rugged; single serotype (no reinfection and vaccine)
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hepatitis A pathogenesis
fecal-oral - infects hepatocytes - often asymptomatic
causes acute hepatitis - NOT hepatotoxic - immunogenic response
1% fulminant hepatitis (quickly lose liver)
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hepatitis A on exam
fever, jaundice, gastroenteritis, tenderness around liver, dark urine, pale feces
history: vaccination? foreign travel, daycare, shellfish
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hepatitis A labwork
IgM = acute; IgG = resolved or vaccinated; serum ALT = liver damage
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hepatitis A treatment
rest, fluids, monitoring; discontinue alcohol and contraindicated meds
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hepatitis E virology
small, naked, icosahedral capsid, + ssRNA
one serotype
endemic to asia, africa, mexico
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hepatitis E pathogenesis
fecal-oral transmission similar to hep A (acute hepatitis usually resolves) but higher mortality especially in pregnant women!
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hepatitis E exam, labwork, treatment
exam: same as hep A (fever, ajundice, gastroenteritis.. travel?..)
labwork: serum ALT
treatment: same as hep A (rest, fluids, monitoring)
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hepatitis B virology
hepadnavirus (hepaDNAvirus) - enveloped, DNA genome, partly double-stranded
one serotype, no reinfection , vaccine
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how does hepatitis B evade immune system?
-replication produces many INCOMPLETE DECOYS!
-replication in hepatocytes leaves behind integrated viral DNA
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hepatitis B pathogenesis
transmitted by blood, sex, birthing
90% have acute hepatitis then clear virus
remaining 10% have fulminant or establish chronic infection
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complications of chronic hepatitis B infection
1. cirrhosis (ongoing cytotoxic attempt to clear virus)
2. kidney damage and arthritis (accumulation of antigen-antibody complexes)
3. hepatic cell carcinoma (integrated viral DNA and ongoing hepatocyte replacement in context or virus infection)
13
hepatitis B labwork
serology for timecourse of infection: surface antigen, surface antibody, core antibody, E antigen
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what is anti-HBc indicative of?
no vaccine - prior infection!!
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hepatitis B treatment
acute: supportive
DAMAGING chronic: polymerase inhibitors and alpha-interferons
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prevention of hepatitis B
vaccination and immune globulin prophylaxis
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what is the relationship between hepatitis B and D?
B is a helper virus to D
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hepatitis D virology
viriod parasite of hep B
encodes single delta antigen (all other parts obtained from hepB infection same hepatocyte)
NOT capable of solo infection!!
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which is worse? co infection or superinfection by hepB+D
superinfection! (pre-existing hep B followed by D) - in co infection, D can't infect all the way because it takes B a while to completely infect - a weak infection by D pretty much
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hepatitis D pathogenesis
spread by blood, sex - delta antigen is hepatotoxic - fulminant hepatitis likely
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hepatitis D labwork
EIA for delta antigen or antibodies against it
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hepatitis D treatment
none effective - liver transplant if meets criteria
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hepatitis C virology
favivirus - enveloped, +ssRNA
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difference in B and C immune evasion
B makes decoys, C has lots of mutations!
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hepatitis C pathogenesis
transmitted by blood, sex, 85% chronic infection with long latency
can proceed to liver failure which is mostly immunogenic
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hepatitis C exam
MILD acute hepatitis
diagnose by EIA followed by RIBA and genotyping
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hepatitis C treatment (second generation)
acute: pegalyted alpha interferon to reduce risk of chronic infection
chronic: attempt to achieve sustained viral response by combined therapy with:
1. ribavirin (viral chain terminator)
2. pegalyted alpha-interferon
3. HCV protease inhibitors: voceprevir or telaprevir
better for serotypes 2 and 3
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