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10.13 Viral Hepatitis A, C, and E
at 1pm by Dr. Amedee
93
Microbiology
Professional
10/14/2011

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Cards

Term
T/F Hepatitis can be caused by protozoa.
Definition
true
Term
What is the genome of hep A?
Definition
+ssRNA
Term
What is the genome of hep C?
Definition
+ssRNA
Term
What is the genome of hep D?
Definition
-ssRNA
Term
What is the genome of hep E?
Definition
+ssRNA
Term
What is the genome of hep G?
Definition
+ssRNA
Term
Which viral hepatitises do we have a vaccine for?
Definition
hep A, hep B
hep E is forthcoming
Term
What viral family is hep A apart of? What is the structure of its virion?
Definition
picornavirus; icosahedral, non-enveloped
Term
How many serotypes of hep A are there?
Definition
1
Term
T/F Hep A is shed in the feces before symptoms.
Definition
true
Term
What is the incubation of HAV?
Definition
"short" 15-45 days (3 weeks)
Term
What are the symptoms of HAV?
Definition
prodrome: fever, nausea, anorexia, pain in RUQ, dark urine, clay-colored stool
icteric: jaundice, pruritis, hepatomegally
Term
T/F Many people infected with HAV do not become icteric.
Definition
true
Term
What percent of HAV infections result in fulminant liver failure?
Definition
.1%
Term
How do you diagnose hep A?
Definition
IgM anti-HAV
Term
How does HAV cause disease?
Definition
viral replicaiton in the liver leads to lymphoid cell infiltration, necrosis of parenchymal cells, proliferation of kupffer cells, biliary stasis and CTL damage to hepatocytes
Term
T/F Chronic infections due to HAV can occur.
Definition
true but they are extremely rare
Term
What abnormal laboratory finding coincides exactly with the symptoms of HAV?
Definition
increased ALT
Term
What's teh infection: disease ratio for HAV in adults? children?
Definition
A 1:1
C 20:1
Term
How long does the patient have IgM and IgG anti-HAV?
Definition
IgM anti-HAV for 3-6 months; IgG anti-HAV for lifetime
Term
Besides the traditional hep a, b, c, etc. what other viruses cause hepatitis?
Definition
CMV, EBV, coxsackievirus, etc.
Term
In a patient presenting with symptoms of hep a, what else should also be in your differential?
Definition
other viral hepatitis, other infecitons (toxoplasmosis and others), drugs, alcohol, gallbladder disease, pancreatitis, autoimmune liver disease
Term
What two tests should you order on a person presenting with symptoms of hep A?
Definition
hepatitis serologies and ultrasound
Term
What are the risk factors for HAV?
Definition
personal contact, poor hygeine, overcrowding, day care, nursing homes, contaminated food (shellfish, vegetables, milk, water), illicit drug use, international travel, MSM
Term
How much has the incidence of HAV declined from 1995 to 2007?
Definition
92%
Term
What percent of adults of US and world have serological evidence of HAV infection?
Definition
<50% of US
>90% of world
Term
How do you treat hep A?
Definition
supportive= anti-itch meds, anti-emetics, rest, adequate nutrition
isolate pt if uncontrolled diarrhea
Term
How do you prevent hepatitis A?
Definition
prophylaxis (improve hygiene or vaccinate)
post exposure: passive immunity with Ig (.02 ml/kg IM)
Term
What type of vaccine is the HAV vaccine?
Definition
inactivated whole virus vaccine (cell culture-adapted virus, inactivated wtih formalin)
Term
What are the commercial names for the hep A vaccine?
Definition
Havrix (glaxosmithkline) and vaqta (merck)
Term
How many doses of the HAV vaccine are there?
Definition
2 doses 6-12 months apart
Term
What is twinrix?
Definition
a vaccine for hep a and b
Term
Who should get the HAV vaccine?
Definition
in1996 the CDC recommended only the at risk population but in 2006 it was recommended as part of routine vaccination of all children
Term
How do you administer HAV Ig? Is it effective?
Definition
administer .02 mL/kg within 2 weeks and it is 80-90% effective
Term
What can you offer a person exposed to HAV to help prevent them getting the diseaes?
Definition
single dose of hep A or Ig asap (give Ig for persons aged >40 years or those with underlying medical condition)
Term
What did hep c used to be called?
Definition
non-A, non-B
Term
Describe the three genes that make the large precursor polyproten of hep C?
Definition
C= nucleocapsid, core protein; conserved
E= envelope (E1 and E2), hypervariable
NS= nonstructural proteins
Term
T/F Envelope proteins and transmembrane proteins are both structural proteins of hep C.
Definition
FALSE! envelope glycoproteins are structure; transmembrane proteins are nonstructural (both are part of hep c)
Term
T/F Hep C does not grow well in tissue culture.
Definition
true
Term
ANtigenic variation for hep C is predominant in what protein?
Definition
envelope glycoprotein E2
Term
How is hep C able to establish such a chronic infeciton?
Definition
exists as a quasispecies which enables immune escape
Term
How many genotypes of hep C are there?
Definition
6
Term
What are the most common strains of hep C in the world? in the US?
Definition
1a and 1b in the world
1a in the US
Term
What is the most common chronic bloodborne infection in the US?
Definition
HCV infection; approximately 3.2 million persons are chronically infected in the US
Term
What is the trend of HCV incidence in the US?
Definition
declined after peak in 1992, since 2003, rates have plateaued
Term
What is the most common risk factor for HCV?
Definition
injection drug-use
Term
How is HCV transmitted?
Definition
percutaneous exposure to infectious blood
Term
Wheredoes HCV replicate?
Definition
initally in monocytes, B and T cells then spread to liver where they replicate in hepatocytes with a high rate of infection
Term
What percent of hepatocytes are infected by HCV and how many virions are produced per day?
Definition
10% of hepatocytes
1x10^12 virions per day
Term
What percent of people with HCV clear the virus and don't develop chornic infection?
Definition
15-25%
Term
What percent of people experience HAV like symptoms 4-12 weeks after infection with HCV?
Definition
20-30%
Term
Infection with HCV results in a chronic carrier state in up to ___% of adults.
Definition
85%
Term
HCV infection is often diagnosed as a result of...
Definition
routine examinations that reveal elevated ALT or when they are screened for blood donation
Term
T/F Chronic HCV diseaes is always severe.
Definition
false, can range from mild to severe
Term
What is the average duration of time from infection with HCV to development of chronic hepatitis?
Definition
10-18 years
Term
What are the late sequalae of chronic hepatitis?
Definition
cirrhosis and HCC
Term
What percent of those chronically infected with hep C go on to cirrhosis?
Definition
20%
Term
What percent of those with chronic HCV go on to develop HCC?
Definition
5%
Term
What percent of those chronically infected with HCV go on to experience fulminant liver failure?
Definition
.1%
Term
What causes disease in HCV infection?
Definition
mainly immune mediated cytokine storm (TH1, CTL, gamma interferon, perforins, apoptosis via NK cells, immune complex formation)
Term
How do certain viral proteins of HCV directly inhibit the immune response?
Definition
inhibit interferon; HCV core binds to TNF receptor
Term
What is the leading cause of liver transplants?
Definition
hep C
Term
What can affect the progression of hep C?
Definition
genetics, immune status, behavioral factors, severeity increased with smoking and alcohol abuse and other co-infections
Term
How many deaths per year are due to hep C?
Definition
8,000-10,000
Term
What are the different tests you can use to check for hep c infection and the pros and cons of each?
Definition
hep c antigens are not detectable in the blood so we screen for antibodies. Antibodies are not found for 1-3 weeks after clinical onset and are absent in some patients. You can measure Ab to multiple hep C antigens by ELISA or other immunoassay
PCR for viral RNA may be more sensitive
Term
What are the three tests used to test for hep C infection?
Definition
check for anti-HCV antibodies via EIA/ELISA
HCV recombinant immunoblot assay (HCV RIBA)
nucleic acid test (NAT) for HCV RNA
Term
What is the treatment for Hep C?
Definition
peglyated interferon alpha plus ribavirin for 24-48 weeks
Term
Pegylated interferon alpha plus ribavirin leads to rapid improvements in ALT levels are disappearance of detectable HCV RNA in up to ___% of patients.
Definition
70%
Term
A response to HCV treatment is considered "sustained" if...
Definition
HCV RNA remains undetectable for 6 months or more after stopping therapy
Term
What is the new treatment for HCV/
Definition
telaprevir (Incivek) from vertex
beceprevir (victrelis) from merck
Term
What is the cure rate when a protease inhibitor is added to conventional hep C treatment?
Definition
80% cure rate
Term
Which hep virus has no family?
Definition
hep E, similar to calici and rubella viruses
Term
What is the genus of hep E?
Definition
hepeviridae
Term
What is the genome and structure of hep E?
Definition
+ssRNA
nonenveloped, icosahedral
Term
How many genotypes/serotypes of hep E are there?
Definition
4 genotypes but only 1 serotype
Term
Is hep E zoonotic?
Definition
man is the natural host but antibodies to HEV like viruses have been detected in primates and other animals. May be found in pigs and associated with eating undercooked pig liver. Also in boars, deer, and camels
Term
What is the major cause of acute hepatitis worldwide?
Definition
HEV, most cases are in developing countries with poor sanitation
Term
T/F Hep E is frequently subclnical.
Definition
true
Term
What percent of hep E results in fulminant liver failure?
Definition
1-3%
(more common in pregnant women 15-25%)
Term
Which people who get hep E are most likely to have symptoms?
Definition
adolescents and young adults (aged 15-44 yoa) and pregnant women
In developed countries, symptoms are more common among older people (>45 yoa) particularly men
Term
Which population usually has mild or no symptoms when infected with hep E?
Definition
children
Term
How long is the incubation period of hep E/
Definition
40 days
Term
What causes the disease in hep E?
Definition
immune response to virus and antigen/antibody complexes
Term
What are the risk factors for hep E/
Definition
poor sanitation
person to person is uncommon and there is no evidence of sexual transmission or tranmission by transfusion
Term
Hwo do you prevent hep E?
Definition
avoid drinking water of unknown purity, uncooked shellfish, and uncooked fruit/vegetables not peeled or prepared by traveler.
passive immunization= high titer IgG (monoclonal antibodies in monkeys)
working on vaccine: virus like particles made in insect cells or bacteria
Term
How do you diagnose hep E?
Definition
should test with IgM but it's not available. Can get IgG in the US but its not routine. antigen test and PCR-feces test are in development
Term
What type of virus is hepatitis G? (family, genome)
Definition
flavivirus; + ssRNA
Term
How common is hepatitis G infection?
Definition
2% of blood donors are positive; 35% of HIV patients are positive
Term
How do you transmit HGV?
Definition
blood borne, maybe sexually, vertically
Term
Where does hep G replicate?
Definition
lymphocytes, not hepatocytes (not shown to cause acute or chronic hepatitis)
Term
How do you diagnose HGV?
Definition
HGV RNA
Term
Being coinfected with HGV can possibly benefit patients infected with...
Definition
HIV
Term
What percent of viral hepatitis is caused by either HAV, HBV, or HCV?
Definition
>95%
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