Viral Heptatitis Flashcards by Emily Prazak

What are the viruses that cause viral hepatitis?

hep A
hep B
hep C
hep D
hep E

hep G

yellow fever

EBV and VZV can cause hepatitis during the course of their invections

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What set of three viruses make up 90% of all viral hepatitis?

hep A, B and C

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Which ones can form chronic infection as well as acute?

B C and D

A and E (the ends and the vowels) only do acute

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What is another name for the hepatitic virus?

GB virus C

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Hep G is in the same family as what other hepatitic-causing viruses?

HCV and YFV (Flavoviridae)

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What are the morphological characteristics of hepatitis G?

RNA virus, ss+ nonsegmented
icosahedral
enveloped

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How is hep G transmitted?

exposure to contaminated blood products in humans

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Individuals with Hep G are likely to be coinfected with what?

hep B and Hep C or both

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What kind of infection does Hep G cause?

hard to say - initially through to be associated with chronic hepatitis and hepatocelluar carcinoma

not probably not hepatocellualr carcinoma and maybe not even hepatitis at all - might infect lymphocytes (maybe important for HIV course)

it’s probably the coinfection with B and C that cause the hepatocellular damage

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What is the viral family for HAV?

Picornaviridae

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What is the viral family for HBV?

hepadnaviridae

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What is the viral family for HCV?

flaviviridae

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What is the viral family for Hep D?

deltavirus

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What is the viral family for HEV?

caliciviridae

CalicEEE

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Which three hepatitis viruses have ssRNA + DNA (group IV)?

HAV
HCV
HEV

also HGV I think

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Which hep virus has partially double stranded DNA (group 7)?

HBV

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Which hep virus has a negative sense ssRNA genome (group 5)?

hepatitis D

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Which two hepatitis viruses are not enveloped?

HAV and HEV are non-enveloped
B, C, and D are enveloped

this makes sense for transmission

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HAV has a protein that is covalently attached to the 5+ end of the genome. Wat is it?

the VPg protein

also has a polyA tail

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Describe the extent of HAV’s capsid resistance

stable at ph 1

resistant to many solvents, detergents and desiccation

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What substances can inactivate HAV?

chlorine treatment of drinking water
formalin treatment
UV radiation

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What’s the route of infection for HAV?

fecal oral

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What cells are first infected by HAV?

cells expressing the HAV receptor 1 glycoprotein (HAVCR-1) - liver and T cells

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How soon before the onset of jaundice does the virus start shedding in stool

10 days

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true or false: HAV is cytotoxic to hepatocytes, causing hepatitis.

false - it's the immune response to virally infected hepatocytes mediated by cytotoxic T cells that cause disease

What percentage of worldwide acute heptaitis cases are caused by HAV?

40%

True or false: 90% of children and 25-50% of infected adults will have asymptomatic, non-productive infections.

false - asymptomatic, but productive

What are the symptoms of an acute HAV infection?

4-6 days with fever, fatigue, nausea, loss of appetitie, abdominal pain, dark urine, jaundice

HAV infections resolve 99% of the time...except....

1 percent will have fulminant infection which is associated with an 80% mortality rate

How do you determine acute HAV infection with serology?

ELISA positive for anit-HAV IgM

WHat are the treatment options for HAV?

mostly just supportive for the actual patient 1. prophylaxis with immune globulin serum given to contacts of an HAV infected individual 2. killed HAV (formalin) vaccine given to children and adults at high risk for infection

HAV and HEV are clinically very similar. WHat are some differences?

HEV has a slightly longer incubation period but disease is slightly more severe with an overall mortality of 1-2%

HEV infection is particularly dangerous for what population?

pregnant women - mortality rate of 20%

Why might HEV be worse in pregnant women?

immunological and hormonal factors probably: maternal immune system is altered in that T cells are reduced up to the 20th week of gestation which may lead to an increased susceptibiltiy to viral infections levels of HCG are up and have a suppressive effect on cell-mediated immunity ultimately, the hepatitis virus doesn't have much cytotoxic effect but it can have some. If you let it go uncontrolled you can get more damage to the synovial cells that line the liver. When you damage those cells you expose the underlying hepatoytes. it's speculated that endotoxins from the gut will gain more access to the hepatitis which is EXTREMELY toxic to hepatocytes

What are the treatment sfor hepatitis E?

no treatments available unfortunately

Describe the morpholog of hep B?

partially DS circular DNA icosahedral enveloped only group 7 we'll learn about

The actual infectious HBV virion is called what?

the Dane particle

Some virions have HBsAg but only the particle and no core, so it's not infectious. Is it immunogenic?

yes - the surface antigen is what triggers the immune response

True or false: the worse you initial symptoms with HBV are, the more likely you are to have chronic HBV and hepatocellular carcinoma.

false - you get more severe symptoms if your immune response is robust so if you have a mild course initially, you're more likely to have chronic disease

Hepatitis B will infect liver cells expressing what?

1. transferring receptor 2. asialoglycoprotein receptor 3. human liver annexin V

What part of the HBV is actually doing the infecting?

HbsAg

What dictates the otucome of HBV infection?

individuals immune response to initial infection

What's the most sure-fire way to get a hep B infection?

contact with contaminated blood (but also in semen, saliva, milk, vaginal and menstrual secretions, and amniotic fluid)

Although the virus starts to replicate in the liver within 3 days of exposure, how long can it take for symptoms to arise?

may take up to 45 days

Worldwide, what proportion of people have been infected with HBV?

1 in 3

HBV serology...

How do you know if someone has effectively cleared an HBV infection completely

check for the HBV genome - if it's present, they're an asymptomatic carrier.

Those that are vaccinated against HBV will only have what on serology?

only anti-HBs | no anti-core or anti-e as you'd see in a resolved infection

Who gets the prophylaxis against hep B with immune globulin serum?

newborns of HBsAg positive moms - within 12 hours of birth individuals within a week of exposure to prevent disease

What are some treamtents available for chronic HBV infection?

lamivudine (RT inhibitory), adefovir, dipivoxil, famciclovir, and pegylated interferon alpha

What is hte morphology of hep D?

SS- circular RNA genome icosahdreal nucleocapside enveloped

How is hep D transmitted?

bloodborne pathogen

Why can Hep D only occur with a HBV infection?

it requires the HBsAg for packaging

How can you get a lab diagnsis for Hep D?

presence of HDV noted by detecting the RNA genome

What is hte morphology of hep C?

SS+ nonsegmented RNA icosahedral enveloped

What percentage of HCV infections become chronic?

70-80%

What can chronic infection with HCV lead to?

cirrhosis or hepatocellular carcinoma, liver failure

How long does it take before symptoms apear?

10-20 years post infection

HCV will infect liver cells expressing what?

CD81 tetraspanin surface receptor uses the lipoprotein receptor to facilitate uptake into hepatocytes

How do HCV proteins promote persistent infection?

they inhibit cellular apopotsis and interfoner alpha action

What is the treatment for HCV infection?

recombinant inferferon alpha or pegylated inferferon alpha, ribavirin, boceprevir and telaprevir

How does genotype affect this?

genotypes 2 and 3 will response to these treatments ,while genotypes 1 and 4 do not response well1

What is the most common genotype here?

1 (wo treatment is hard)

Why can't we develop a vaccine forr HCV?

It mutates too rapidly

What is the morphology of yellow fever virus?

ss+ nonsegmented RNA virus icosahedral enveloped

What are the surface glycoproteins seen on yellow fever virus?

E1 and E2

How is YFV spread?

the aedes mosquito

True or false: like the other haptitis-causing viruses, YFV is not directly cytotoxic, rather disease is caused by the inflammatory response.

false - this one is the only hepatitis that is directly cytotoxic but of course there is plenty of damage that occurs with the immune response still

Describe the presentation of YFV?

severe systemic disease with flu-like symptoms, loss of lvier/kidney/heart function, hemorrhagic fever and shock mortality rate as high as 50%

What's the treatment for YFV?

supportive care vector control measures and vaccination fo rpreventative measures