Lecture 17: Hepatitis Virus Flashcards
Which 2 hepatitis viruses provide immunity to one preventing infection with the other?
HBV and HDV
What is hepatitis?
An inflammation of the liver that can be caused by infections and by other means.
Causes: Viruses, drugs, and auto immunity
True or False? Over 4 million carriers of hepatitis viruses, HBV and HDV exist in the US and many are unaware of their carrier status
False! HBV and HCV
HCV causes more deaths than HBV?
Yes, 12,000 (HCV) and 3,000 (HBV)
-Worldwide 1.5 million die each year
What two hepatitis viruses cause mild acute disease, but can lead to carrier status, chronic liver damage, and liver carcinoma
HBV and HCV
What is the result of liver damage?
1) increase in plasma transminase (SGOT)
2) Increase in Bilirubin –> Jaundice and 75% non-jaundiced = Anicteric
Which two hepatitis viruses are stable, Non-Enveloped and transmitted via Fecal/oral?
HAV and HEV
Which viruses that cause hepatitis are enveloped and unstable?
HBV, HCV, HDV
Where do hepatitis viruses replicate?
in hepatocytes and can initiate their destruction
Which hepatitis viruses are DNA and which are RNA?
DNA= HBV
RNA= HAV, HCV, HDV (incomplete RNA virus), HEV
How are HBV, HCV, and HDV transmitted?
Through exchange of “Percutaneous, permucosal “ AKA bodily fluids (Blood, semen, saliva, mother’s milk, etc)
***Less hardy they have envelope and will easily dry out.
Which hepatitis viruses cause chronic infection?
B, C, and D
Which hepatitis viruses cause acute infection?
A and E
Which hepatitis viruses require clean blood supply for prevention?
B, C, D
What is the primary measure for prevention of hepatitis B?
1) immunization
2) Pre-exposure prophylaxis with hepatitis BN vaccine or post exposure prophylaxis with hep B immuno globulin (HBIG) and hepatitis B vaccine—-> This will also PREVENT HDV infection.
Are there products to prevent hep C?
No, but primary strategies are blood donor screening and risk behavior modification.
In persons who are chronically infected with HBV what can be done to prevent HDV superinfection?
risk behavior modification is primary measure
Is there specific products available for prevention of Hep E?
No, primary measure to prevent disease is to ensure the safety of drinking water as well as sanitation procedures.
Which hepatitis viruses can lead to chronic infections and persons that become carriers capable of further spreading these infections.
a substantial percentage of HBV, HCV, and HDV
Which hepatitis virus is very rare in the USA, is relatively common is some “developing” countries, where it takes a substantial toll among pregnant women
HEV ( about 20-25 % fatality)
What are some characteristics of Hep A ?
- RNA Picornavirus
- Noneveloped (sturdy)
- fecal oral transmission
- single serotype worldwide (1 major strain)
- no chronic infection; acute and asymptomatic !!!!!!
- protective antibodies develop in response to infection = lifelong immunity
- vaccine (inactivated) available since 1996
Which two viruses are similar in pathology?
HAV and HEV are similar and primarily cause diseases in the developing world.
- Can lead to jaundice (about 2 weeks)
- Both are spread via fecal-oral.
- Outbreak is due to contaminated food and water because of undercooked shellfish and daycare centers.
- Can be also spread from mucosa –>mucosal contact & Blood–>Iv transfer.
What is the treatment of HAV?
- Treat with pooled IgG
- vaccine available
- no carriers
Characteristic of Hep B
-DNA hepadnaviridae
-Enveloped (unsturdy)
-Transmission
1) Sexual 2) Parenteral 3) Perinatal
- single serotype worldwide
-Acute disease and asymptomatic infection (90%)
-Chronic infection 10 %
-Protective antibodies develop = lifetime immunity
-Vaccine (inactivated) available since 1981
or if you make Abs you are protected.
What does the outer membrane of Hep B contain? (Think spikes)!
contains hepatitis B surface antigen (HBsAg) which circulates in blood as particles.
What is the primary component of hepatitis B vaccine?
HBsAg; this antigen induces a protective neutralizing antibody that provides long-term protection.
The inner core of the virus contains hepatits B core antigen called what?
HBcAg
Who is the high risk population for HBV?
- health care personnel
- dialyses patients
- people from high risk areas
- military personnel
- people with multiple sex partners
- IV drug abusers
How is HBV transferred?
- Transfusions (blood)
- Sexual contact (blood)
- poor sanitation(blood)
- I.V drugs
- Birth canal
How are neonates affected?
90 % infected
90 % become carriers
(cant clear infection)
What are the results of severe chronic hepatitis?
- Liver tumors
2. cirrhosis (loose functions bc of scarring)
What two things are responsible for both the pathology of HBV and eliminating the viral infection?
Cell mediated immunity and inflammation
What percent of individuals with HBV develop an insufficient immune response, and the infection becomes chronic?
5-10% these individuals are “carriers” and will shed HBV indefinitely.
What are the three results of chronic HBV infection?
1) asymptomatic, mild chronic hepatitis, or severe chronic hepatitis. (later results in cirrhosis or cancer)
HCV causes a similar pathology to which virus , but has a higher carrier & death rate?
HBV is less severe than HCV because HCV does not have a vaccine.
What genes, and proteins does the Hep B viral genome contain?
GAG, POL, ENV = Genes
HBcAg(capsid protein) ,HB?Ag, HBsAg, and X-protein
Functions: Capsid, polymerase and spike, and regulation respectively.
What determines the course of disease for Hepatits B?
The immune response; in majority of individuals immune repsponse can eliminate the virus infection with no lasting effects
When does the HBV infection become chronic?
In a minority of individuals this occurs when an individual doesn’t mount a sufficient immune response–>leading to cirrhosis and hepatoma (cancer)
What can be used diagnostically in HBV infections?
Liver enzymes m HBcAg, HBeAg, and HBsAg, and antibody to HBcA, HBeAg, and HBsAg
- in 80-90% of individuals the immune response will effectively resolve the infection.
- These individuals will develop significant anti HBsAg antibody with a corresponding drop in HBsAg.
*** Spike level of Ag most important.
How is a HBV carrier determined?
In these individuals the anti-HBsAg antibody level stays low (not a lot of Ab’s against spikes), while HBsAg remains high. If this goes on for over 6 months then person is diagnosed as a carrier.
