Hepatitis – Microbiology – Flashcards

• Upper right quadrant ab. pain, nausea, anorexia, fatigue, fever
• Jaundice, hepatomegaly
• Elevated: liver enzymes, bilirubin in blood and urin, Alkaline phosphatase, LDH

• Picornaviridae, Enterovirus group
• (+)ssRNA virus
• very stable in environment
• causes acute or asymptomatic infection
• "infectious hepatitis"

• Fecal/oral due to crowding and poor hygiene
• community outbreaks
• assymptomatic = source of new infections

Incubation period: avg = 30 days

Jaundice:

• >14 yrs 70-80%
• 6 - 14 yrs 40%-50%

Complications: Fulminant hepatitis, cholestatic hepatitis

Typical disease: acute for weeks

Definitive diagnosis of acute infection:

α-HAV IgM in serum

Definitive diagnosis of past infection:

α-HAV IgG

• Hepadnaviridae family
• enveloped, dsDNA
• replicates via RNA intermediate
• heat and pH resistant
• humans are only reservoir
• acute and chronic infections

• 90% acute infections
• Chronic persistent (asymptomatic)
• Chronic active (symptomatic)

Incubation period: avg = 100 days

Jaundice: >5 yrs 30-50%

Chonic infection: more likely in children <5 yrs

Acute infection more likely in adults

15-25% die of chronic liver disease

active replication of virus

-more accurate than HBeAg

HBsAg +

HBeAg +/-

α-HBcAg IgM +

α-HBcag IgG + right after infection; - rest of the time

HBsAg -

HBeAg -

α-HBsAg +

α-HBcAg IgM -

α-HBcAg IgG (total) +

HBsAg +

HBeAg -

α-HBcAg IgM -

α-HBcAg IgG (total) +

α-HBeAg +

DNA polymerase -

HBsAg +

HBeAg +

α-HBcAg IgM -

α-HBcAg IgG (total) +

DNA polymerase +

• ssRNA, unclassified virus
• contains HDV Ag derived from HDV
• contains HBsAg derived from HBV
• needs HBV as helper to code its surface protein
• aquired as coinfection or superinfection of HBV

• percutaneous exposures
• permucosal exposures

• Intravenous drug users and their partners

severe acute disease - mostly adults

low risk for chronic infection

serology will show ?-HBs in later weeks

usually from contracting HDV while person already has a chronic HBV infection

-high risk of severe chronic liver disease (chronic active or fulminant hepatitis)

serology: will continually have HDV-RNA, HBsAg, α-HDV IgM; will not have α-HBs

acute

high titers in chronic during times of reactivation

• a NANB hepatitis virus
• non enveloped, (+)RNA
• related to calicivirus

• fecal/oral
• acute sporadic outbreaks

Incubation: avg 40 days

Case-fatality rate: pregnant 15 - 25%

severity increases with age

Flavivirus; (+)ssRNA

mild acute hepatitis that usually becomes chronic persistent

can be found in coinfections with HC, HBV and HIV

• Flavivirus; (+)ssRNA
• accounts for 90% of NANBH infections
• reservoirs = humans and chimpanzees
• causes chronic infections
• undergoes rapid antigenic variation in infected individuals

percutaneous route

• injecting drugs
• needle stick injuries
• formerly blood transfusion (pre 1990)

permucosal

Incubation: avg 8 - 9 weeks

Jaundice: <25%

chronic infection: 70 - 85%

chronic hepatitis: 60 - 70 %

cirrhosis 5 - 20% (takes 10 - 20 yrs of infection)

• increased alcohol intake
• age >40 yrs at time of infection
• HIV co-infection

1. test for presence of anti-HCV
2. if positive, confirm with RIBA test
3. Qualitative (yes/no) and Quantitative (viral load) PCR tests