Microbiology Flashcards
What type of virus is HAV?
+ssRNA naked icosahedral picornavirus
Transmission of HAV?
fecal oral
- acid stable
- found in contaminated water in developing countries
How to inactivate HAV?
- Chlorinate
- Bleach
- UV irradiation
- Boil
HAV transmission in USA?
- shellfish
- travelers to endemic areas
HAV symptoms in children?
No jaundice with vomit
- often asymptomatic
- shed virus to family
HAV symptoms in adults?
Jaundice and vomit
-smokers acquire an aversion to smoking
Duration of HAV?
- one month
- self limiting
- no chronic state
Who should get the HAV vaccine?
- high risk endemic areas
- liver disease
- homosexuals
Type of virus HBV?
partially dsDNA covalently closed circular hepadnavirus with envelope (cccDNA)
- replicates in and out of nucleus through RNA intermediate
- fully ds during replication
Key enzyme in HBV?
reverse transcriptase
-doesnt integrate into host
HBV transmission?
- sex
- needles
- vertical transmission from mother
Who is at high risk of Chronic HBV?
Newborns (90%)
Extrahepatic manifestations of HBV?
- arthralgias
- PAN: beads on a string (decreased GFR)
- MGN
HBV liver enzymes?
Elevated ALT>AST and then fall after infection
-normal ALT early in neonatal hepatitis
HBsAg+?
active infection
HBeAg+?
High infectivity
Anti-HBc?
- positive in window period
- Ab started to bind Ag, neither Ag nor Ab detected
- false reassurance
Anti-HBe?
low infectivity
Anti-HBsAg?
Immunity
Immunized serology?
-Anti-HBc and Anti-HBe
Long term complications of HBV?
- cirrhosis
- HCC
HDV virus type?
-ssRNA circular enveloped
What does HDV require to be infectious?
HBsAg
Coinfection?
HBV and HDV simultaneously
-low risk of chronic
Superinfection?
HDV infection on top of preexisting HBV
- worse outcome, high risk of severe chronic
- HDV uses HBV surface Ag to form envelope and spread
Treatment for HBV?
- NRTI (Lamivudine) that inhibits reverse transcriptase
- Tenofovir
- Entecavir
- IFN-gamma
- give to pregnant women prior to delivery
- give baby IgG + HBV vaccine for active and passive immunity
HCV type of virus?
+ssRNA enveloped Flavivirus
HCV transmission?
- Transfusions
- IVDA
- Sex (more common in HBV)
Why is HCV very infectious?
antigenic variability
- polymerase lacks 3’ to 5’ exonuclease activity leading to mutations
- more infectious than HIV
How much HCV becomes chronic?
60-80%
Long term complications of HCV?
- Cirrhosis
- HCC
ALT levels in HCV?
rise and falls by 6 months indicates acute hepatitis
Anti-HCV Ab and immunity?
antibodies may be present but not confer immunity due to HCV ability to mutate
Chronic HCV requirements?
viral RNA persists for 6 months
Cryoglobulins associated with what?
HCV
-precipitate with cool temp containing IgM
Treatment of HCV?
- Ribaviron
- IFN alpha
- protease inhibitor (NS5B)
Leading cause of liver transplant?
HCV
HEV type of virus?
Naked icosahedral RNA hepevirus
Pregnant woman with acute liver disease dies?
HEV
Marker for higher HBV infectivity?
HBeAg
-secreted by infected cells
HCV and HIV confections?
shorter time to cirrhosis
Keys to HCV replication?
- forms membranous web
- Lipo viral particle forms with HCV and VLDL
Most common risk factors for HAV transmission?
- international travel
- IVDA
Most common risk factors for HBV and HCV transmission?
- IVDA
- multiple sex partners
Major risk factor for HDV transmission?
IVDA
Incubation period for HAV?
2-8 weeks
Incubation period for HCV, HBV, HDV?
6 weeks to 6 months
Chronic hepatitis?
viral Ag > 6 months
Immune tolerant HBV?
- normal ALT
- high HBeAg and HBV DNA
- infected as infant
HBeAg+ immune active HBV?
- HBsAg+ longer than 6 months
- HBeAg+
- anti-HBe negative
- high serum HBV DNA
Inactive carrier of HBV?
- HBsAg+ > 6 months
- HBeAg negative
- Anti-HBe+
- low HBV DNA
HBeAg-, immune active HBV?
- HBsAg+ > 6 months
- HBeAg-
- Anti-HBe+
- low HBV DNA
Diagnosis of HAV?
- HAV IgM for acute
- HAV IgG for prior exposure
- increased ALT
Diagnosis of HEV?
- HEV IgM for acute
- HEV IgG past infection
Diagnosis of HDV confection?
IgM and IgG both detected
Acute HCV and ALT levels?
elevated >7x normal
