Hepatitis A & B Flashcards
in hepatitis A, ___ is increased (antibody)
in hepatitis A, IgM is increased
describe the classification of Hep. A
“infectious hepatitis”
picornaviridae
non-enveloped, (+ve) ssRNA
Hep A is not affected by ___ and survives prolonged storage at ____
Hep A is not affected by anionic detergents and survives prolonged storage at 4 C or below
Hep A is inactivated by ____
Hep A is inactivated by chlorine 1ppm for 30 mins, UV radiation
the mode of transmission for Hep A is ____
the mode of transmission for Hep A is fecal-oral route
- close person contact: household, sexual, child day-care
- contaminated food and water: infected food handler
describe the pathogenesis of HepA
- ingestion of virus
- asymptomatic incubation
- hematogenous spread (intestinal epi. → liver)
- replication in liver (hepatocytes & Kupffer cells)
- virus enters intestine with bile
- 99% individuals complete recovery after 2-4 weeks
HepA undergoes hematogenous spread and travels from ___ to ____
HepA undergoes hematogenous spread and travels from intestinal epi. to the liver
HepA replicates in ____ (especially ___ & ____) and then enters the ___ with ___
HepA replicates in the liver (especially hepatocytes & Kupffer cells) and then enters the intestine with bile
diagnosis of HepA requires detection of ____
diagnosis of HepA requires detection of the antibody anti-HAV IgM
in HepA, antibody protection is ____
in HepA, antibody protection is lifelong (no reinfection)
describe the classification of HepB virus
“serum hepatitis”
hepadnaviridae
enveloped, circular, partially dsDNA
describe the purpose of HBcAg
HBcAg (major core antigen) surrounds genome and core enzymes
describe HBsAg
HBsAg (surface antigen) is present in the envelope and indicates an active infection
describe HBeAg
HBeAg is a secreted protein that is an indicator of transmissibility
HBV vaccine is composed mostly of ____
HBV vaccine is composed mostly of HBsAg
describe the replication of HBV
- HBV replicates through an RNA intermediate (virus encodes reverse transcriptase)
- HBV produces and release antigenic decoy particles (HBsAg)
HBV replicates through _____
HBV replicates through an RNA intermediate (virus encodes reverse transcriptase)
describe the 3 modes of transmitting HepB
- parenteral: IV drug users, transfusion, dialysis, acupuncture, tattooing, health workers
- sexual contact: MSM (highest risk), sex with IV drug users, sex with sex workers
-
perinatal: mother (HBeAg+) → infant
- high prevalence in China, SE Asia
- neonates & children < 1yo: 90% risk of chronic infxn due to immature immune system
describe the pathogenesis of HepB
- HBV replication in hepatocytes within 3 days
- symptoms not observed for 45+ days
- copies of HBV genome integrate into hepatocyte chromatin, remain latent
- insufficient T-cell response results in occurrence of mild symptoms, inability to resolve infection & development of chronic hepatitis
describe the 3 proposed mechanisms of oncogenicity caused by HBV
describe what anti-HBc IgM indicates
marker of acute infection, especially while infection is being resolved or during the “window” period
describe what anti-HBc IgG indicates
past or chronic infection
describe what the presence of HBeAg indicates
active replication of virus (infectiveness)
describe what the presence of anti-HBeAg indicates
virus no longer replicating
describe the change in antibodies and antigens during an acute HBV infection
describe events during HBV chronic infection
describe the purpose of hepatitis B immunoglobulin (HBIG)
- exposed within 48 hrs of incident
- neonate of mothers +ve for HBsAg & HBeAg
