Hepatitis A to E Flashcards
Are the symptoms of acute viral hepatitis similar for all the viruses?
Yes. You could not tell which virus caused your symptoms without doing either serology or nucleic acid testing
All infections with Hepatitis viruses A to E are ________ infections
systemic
Describe the structure of Hepatitis A Virus (HAV), A-acute
Picornavirus, +ssRNA, Naken virus
Naked, very stable virus, stable in stomach acid
What is the primary route of HAV?
Fecal-oral
Are any HAV infections chronic?
No - all infections are acute infections
T/F: In regards to HAV, alcohol-based hand sanitizers are better than washing hands
FALSE - washing hands is better than alcohol-based hand sanitizers!
How is HAV shed?
In feces 1-2 weeks before symptoms and during symptoms
Once infected with HAV, how long is the person protected?
There is protection for life against reinfection
When infected with HAV, when is the person more likely to get jaundice?
If they become infected with HAV as an older child/adult.
Conversely, very young children and babies rarely develop jaundice when infected
What type of vaccine is available for HAV?
Inactivated virus vaccine
The vaccine has high efficacy in protecting from infection
If exposed to HAV, post-exposure prophylaxis:
1) Vaccination within 2 weeks of exposure
2) But if older and the risk of complications is high, or immunocompromised, or have preexisting lier damage, the recommendation is for both the vaccine and IgG at distal sites
3) Babies under one year of age should get IgG only
Describe the structure of Hepatitis E virus (HEV)
Own Family-Hepevirus = Hep E virus, _ssRNA, Naked virus
What is the primary route of infection for HEV?
contaminated drinking water and fecal/oral
HEV is a significant source of ________ outbreaks worldwide but not in the US
hepatitis
What type of infection is HEV?
Acute, no chronic
How does HEV affect pregnancy?
A high fatality rate in pregnancy
Think H E V with the E standing for expecting
What is the Vaccine for HEV?
No available vaccine or post-exposure prophylaxis
Describe the structure of Hepatitis C Virus (HCV)
Flavivirus, +ssRNA, enveloped
How is HCV spread?
-Primary spread is through shared needles, but it can spread through sex and vertical transmission
-Not fecal-oral
-Bloodborne infection
What is the risk of infection of HCV from a needle stick exposure?
0.2% (old number is 3%)
What is HCV known for?
-Its high number of chronic infections (H C V, the C is for chronic)
-If infected, about 80% will become chronically infected
-It is known as the silent infection because many do not know they’re infected
What effect can HCV have on the liver?
-After several years of infection, can develop cirrhosis or liver disease (some never develop the disease)
-HCV infection is one of the top reasons for a liver transplant in the US
In HCV, what are the CD8+ CTLS causing?
Liver damage by killing infected cells
What is the vaccine for HCV?
-No vaccine and no post-exposure tx to prevent infection
(Even though there are drugs to treat HCV, there is NO recommended post-exposure prophylaxis if a healthcare worker is exposed)
There is a treatment with HCV specific antivirals; the 3 classes are against the:
1) Viral protease - stops replication after the translation of the +ssRNA. The protease can’t cleave the polyprotein, no viral polymerase is liberated, and no viral replication takes place
2) Viral polymerase - stops the virus from replicating the viral genome
3) Viral protein NS5A - interferes with genome replication and assembly
What is the cure rate of HCV when treated with antivirals?
-Depending on the genotype of HCV, the cure rate is over 90%, but a person can become re-infected if re-exposed
-Tx is expensive
Describe the structure of Hepatitis B Virus (HBV)
Hepadnavirus (Hepa DNA virus), -ss/ds DNA virus, enveloped
How does HBV replicate?
-Through an RNA intermediate
-*HVB has a reverse transcriptase
T/F: HBV is a bloodborne pathogen
TRU
How is HBV spread?
sexual contact, needle sharing (IDU)/needle stick, during pregnancy/delivery
How long can HBV last on a surface?
Can last for 7 days dried on a surface, even though it is an enveloped virus
**If a needle stick with a known HBV positive source, _____ will become infected if not protected by vaccination
30%
If infected with HBV as an adult, what is the chance you will become chronically infected? An infant?
-If infected as an adult, there’s only a 5% chance
-If infected as an infant through vertical transmission, there’s a >90% chance of becoming chronically infected
For Hepatitis B, the presence of __________ means you are actively infected and can infect other people.
HBsAg (Hepatitis B surface antigen)
For Hepatitis B, if you also have _______, you have a high level of virus in your blood and are very infectious
HBeAg (Hepatitis B e antigen)
An HBV ________ vaccine is recommended for all infants and anyone with potential contact with HBV
subunit
-Some people do not respond to the vaccine from the first 3 doses are are revaccinated.
The HBV subunit vaccine contains only the ______
HBsAg
Describe tx after an exposure event with the following scenarios:
-If you are unvaccinated or have low titers
-If you are a vaccine non-responder
-Baby born to infected people
-If you are unvaccinated or have low titers, you will receive the vaccine and HBIG (Hepatitis B
Immunoglobulin) in different arms
-If you are a vaccine non-responder, you get 2 shots of the HBIG one month apart
-Babies born to infected people will also receive one shot of HBIG and the vaccine series soon after birth.
There are treatments for HBV. The ___________ is the target of the antivirals
HBV reverse transcriptase
-The tx is rarely a cure, and, once started, usually goes on for life
Describe the structure of Hepatitis D Virus (HDV)
A defective/enveloped Negative strand circular RNA virus, Deltavirus family
HDV must infect a cell already infected with ______ to produce infectious virus
HBV
-Cannot productively infect a cell on its own
What does HDV use to coat its’ virus?
HBV’s surface antigen, HBsAg
What is the transmission of HDV
Same as HBV (bloodborne)
What is the vaccine for HDV?
There is a vaccine to prevent HDV infection if you are not already infected with HBV. It is the HBV vaccine. If you are not infected with HBV and are protected against the HBV infection, you cannot be infected with HDV
(If she asks if HDV can be prevented with a vaccine, the answer is yes)
T/F: Infection with HBV alone is much worse than an infection of both HDV and HBV
FALSE - Chronic infection with both HDV and HBV is much worse than infection with HBV alone
Why?
-Higher levels of cirrhosis
-Higher chance of liver failure and potentially a higher risk of hepatocellular cancer
What treatment makes symptoms better for HDV infections?
Type I interferon (but it helps only some infected people)
What are the two ways to get infected with HDV?
-Co-infection
-Superinfection
What is co-infection?
HBV and HDV infections occur at the same time
In co-infection, only ____ go on to chronic infection with HDV and HBV
2%
What post-exposure prophylaxis is used with co-infection?
The one that is used for HBV is used here
(Vaccine and HBIG)
What is superinfection?
Here you are already infected with HBV, and then you get infected with HDV
What can happen with superinfection?
-Get acute hepatitis
-80-90% will develop chronic infection with HDV
What post-exposure prophylaxis is used with superinfection?
Since you are already infected with HBV, there is NO effective post-exposure prophylaxis
