2. THE LIVER
FUNCTIONS OF THE LIVER:
– MAKES PROTEIN NEEDED FOR BLOOD
CLOTTING
– STORES VITAMINS, IRON AND GLYCOGEN
– METABOLIZES SUGAR, PROTEIN AND FAT
TO PRODUCE ENERGY
– REMOVES WASTE PRODUCTS AND
FILTERS TOXIC SUBSTANCES FROM
BLOOD
Enzymes (proteins) from the liver are normally
found in the blood as a result of normal aging
and degeneration of liver cells (called LFT’S –
liver function tests)
– ALT Almandine aminotransferase
– AST Aspartate aminotransferase
– GGTP Gamma -glutamyltransferase
3. HEPATITIS - INFLAMMATION OF THE LIVER
CAUSED BY:
VIRUSES - HEPATITIS A, B, C, D, E, G
OTHER INFECTIONS
(MONONUCLEOSIS)
CHEMICALS
ALCOHOL
ACETAMINOPHEN
Acute hepatitis is where the disease develops quickly, has symptoms and lasts
less than 6 months.
Chronic hepatitis is where the symptoms and disease last longer than 6 months.
ACUTE HEPATITIS CAN RESOLVE TOTALLY OR GO ON TO A
CHRONIC STAGE
4. Hepatitis Viruses. Diseases
Hepatitis A Hepatitis B Hepatitis C Hepatitis Delta Hepatitis E
Virus family Picornavirus Hepadnavirus Flavivirus
Circular RNA
similar to plant
viroid
Similar to
Calicivirus
Nucleic acid RNA (+ sense)
DNA (partially
double strand)
RNA (+ sense) RNA (- sense) RNA (+ sense)
Disease
caused
Infectious
hepatitis
Serum hepatitis
Non-A, non-B
hepatitis
Enteric non-A,
non-B hepatitis
Size ~ 28nm ~40nm 30 - 60nm ~ 40nm 30 - 35 nm
Envelope No Yes Yes Yes No
5. A B C D E G
Disease
Infectious
hepatitis
Serum
hepatitis
Non-A, non-B
hepatitis
Post
transfusion
hepatitis
Delta agent
Enteric
non-A,
non-B
hepatitis
Factors
of the
trasmiss.
Feces
Blood and
body fluids
Sexual
contact
Blood and
body fluids
Sexual
contact
Blood and
body fluids
Sexual contact
Feces
Blood and
body fluids
Transmission
Enteric
Fecal-Oral
Parenteral
Percutaneou
s
Permucosal
Parenteral
Percutaneou
s
Permucosal
Parenteral
Percutaneous
Permucosal
Enteric
Fecal-Oral
Parenteral
Percutaneous
Permucosal
Sexual
transmission
Yes
(especially
homosexu
al)
Chronic
infection
No Yes Yes Yes No Yes
Incubation 15 - 20
45 - 160 14 - 180 15 - 64 16 - 60 ?
6. A B C D E G
Carcino-
genesis
No
Hepatocellul
ar carcinoma
Hepatocellular
carcinoma
Hepatocellular
carcinoma
No ?
Cirrhosis No Yes Yes Yes No ?
Severity of
disease
Usually
mild.
Very low
mortality
Sometimes
severe
1 -2%
mortality
Usually (80%)
asymptomatic
Up to 4%
mortality
Super-infection
with HBV -
often very
severe with
high mortality
rate
Co-infection
with HBV -
often severe
Usually
mild
except in
pregnancy
Asymptomatic
to mild
Prevention Vaccine Vaccine
Behavior
Modification
Blood
screening
Behavior
Modification
HBV vaccine
Safe
water
No
vaccine
Chemo-
therapy
Peginterferon/
Ribovirin
7. Hepatitis A virus
Picornaviruses family
RNA, naked, icosahedral, 15-20 nm,
cubic type of the symmetry
• can be cultivated in а
variety of tissue cell
cultures, but growth in cell
cultures requires long
adaptation
8. HAV Symptoms
• Flu-like
– Fever, fatigue, nausea, vomiting, loss of
appetite, and general malaise
• Jaundice, pale colored stools, dark urine
• Children usually experience no symptoms
9.
10. HAV Prevention
• Hygiene (e.g., hand washing)
• Sanitation (e.g., clean water sources)
• Hepatitis A vaccine (pre-exposure)
– 2 shots within 6-12 months
– Twinrix
• Immune globulin (pre- and post-exposure)
Sterile preparation of concentrated antibodies (immunoglobulins) made
from pooled human plasma
– Only plasma tested negative for hepatitis B, HIV, and antibodies to
hepatitis C are used
• When administered within 2 weeks after an exposure to
hepatitis A virus, IG is 80 – 90% effective in preventing
hepatitis A
12. Three important HBV antigens are:
• (1) surface antigen (НВsАg),
- is produced during viral replication in amounts far in excess of that
needed for viral envelope production. It оссurs in the blood stream on
small spheres and filaments in quantities often 1,000 or more times
greater than complete virions.
- is responsible for the ability of the virus to infect its hosts;
! antibody to surface antigen (anti-НВsAg) confers immunity.
• (2) core antigen (НВcАg),
- represents the outer covering of the nucleocapsid.
! The presence of IgM antibody to НВcAg indicates acute rather than
chronic hepatitis В.
(3) е antigen (НВeAg),
а nonparticulate component of the viral core.
! The presence of НВeAg in the blood indicates а strong likelihood that
the blood is infectious.
13. Structure of HBV
Hepatitis B surface
antigen HBsAg
lipid layer
from host cell
nucleocapsid
Hepatitis В core antigen HBcAg proteins (coded by
viral genes)
Hepatitis В e antigen HBeAg
17. Three clinic forms are differentiated
• healthy HBV carriers,
• chronic persistent hepatitis (CPH) without viral
replication,
• chronic aggressive hepatitis (CAH) with viral
replication and a progressive course.
18. Symptoms
– Jaundice
– fatigue/abdominal pain
– appetite loss
– nausea/vomiting
– mild fever
– dark urine
• One third of adults & 90% of children have no symptoms
• Symptoms last 1-4 weeks up to 6 months
• 90-95% recover within 6 months with lifelong immunity
• 50% develop acute liver disease
19. • Clinical course – 10% of adults who are infected do not clear the
virus* and develop what is called Chronic HBV infection.
– These patients develop chronic liver disease which can be either
persistently mild or aggressive.
20 – 25% of these patients die prematurely due to cirrhosis or liver
failure.
* 30 – 50% of all infected 1 to 5 year olds and 80 – 90% of all
infants develop chronic infection
20. Hepatitis B virus infection
Of the total number of
those infected, a small
percentage die from
cirrhosis (top picture)
and primary liver
cancer (bottom picture)
24. Hepatitis B: Disease Progression
Acute
Infection
Chronic
Infection Cirrhosis Death
1. Torresi J et al. Gastroenterology. 2000.
2. Fattovich G et al. Hepatology. 1995.
3. Moyer LA et al. Am J Prev Med. 1994.
4. Perrillo R et al. Hepatology. 2001.
5%-10% 1
10-30% 1
23% within 5 years
Liver Cancer
(HCC)
Chronic HBV is the 6th
leading cause of liver
transplantation in the
US4
Liver
Transplantation
Liver Failure
(Decompensation)
2-6%
90% in perinatal
30-90% in children<5yrs old
5% in healthy adults
Higher in HIV, immune suppressed
25. Laboratory Diagnostics in HBV Infections
Status Diagnostic test
Acute infection HBc-IgM, HBs-Ag
Vaccine immunity HBs-IgG
Recovered, healed HBs-IgG, HBc-IgG
Chronic, patient infectious HBe and HBs-Ag, PCR
Exclusion of HBV HBc-IgG negative
Serology inconclusive, mutants,
therapeutic monitoring
Quantitative PCR
26. The HBV Panel - Interpretation
Test Results Interpretation
HBsAg
anti-HBcAg
anti-HBsAg
Negative
Negative
Negative
The patient is susceptible to an HBV
infection and has not been exposed
previously to the virus
The patient has not been vaccinated
HBsAg
anti-HBcAg
anti-HBsAg
Negative
Positive
Positive
The patient is immune to HBV as a result
of having been infected previously
(indicated by the presence of anti-HBc
antibodies which would not occur if the
patient had been vaccinated)
HBsAg
anti-HBcAg
anti-HBsAg
Negative
Negative
Positive
The patient is immune because of
vaccination against HBV
27. HBsAg
anti-HBcAg
anti-HBcAg
IgM
anti-HBsAg
Positive
Positive
Positive
Negative
The patient has an acute HBV infection. Any anti-
HBsAg antibodies that have been made are
complexed with the large amount of the antigen
and are thus undetectable
HBsAg
anti-HBcAg
anti-HBcAg
IgM
anti-HBsAg
Positive
Positive
Negative
Negative
The patient has a chronic HBV infection.
The IgM anti-HBc has waned
HBsAg
anti-HBcAg
anti-HBsAg
Negative
Positive
Negative
The patient may be in the recovery phase of an
acute HBV infection. This patient could be infected
and thus a carrier of HBV. The inability to detect
HBsAg may result from it being complexed with
anti-HBsAg antibodies in the "window" phase
Other possible interpretations are that the patient is
distantly immune to HBV but the test was too
insensitive to detect anti-HBsAg.
There may also have been a false positive for anti-
HBcAg and the patient is actually uninfected.
28.
29. Treatment
• Supportive care is the major treatment. Anti-HBV immune globulin
is effective soon after exposure. It can also be given neonatally to
children of HBsAg-positive mothers. Ideally, the immune globulin
should be administered within 24 hours of birth or exposure and is
probably not effective after one week from exposure.
• There are three FDA-approved drugs for treating hepatitis B.
- Interferon-alpha 2b (Intron A - Schering-Plough) is a protein that
mimics the cell’s natural defenses against viral infection.
- Hepsera (Adefovir Dipivoxil – Gilead Sciences) is a nucleotide
analog that inhibits HBV DNA polymerase (reverse transcriptase).
Use is indicated for the treatment of chronic hepatitis B in adults
with evidence of active viral replication and either evidence of
persistent elevations in serum aminotransferases (ALT or AST) or
histologically active disease.
- Lamivudine (Epivir HBV - Glaxo SmithKlein). This is 3TC which is
a reverse transcriptase inhibitor that is also approved for use inn HIV
infections. As with all reverse transcriptase inhibitors, the appearance
of resistant mutants is a problem. Hepsera can be used in patients
with Epivir-resistant mutant virus.
30. Vaccination
• This is the best preventative strategy. The current vaccines are subunit
vaccines made in yeast that has been transfected with a plasmid that
contains the S gene (that codes for HBsAg). The HBV vaccines go
under the names of Recombivax-HB (Merke) and Energix-B (Glaxo).
In addition, there is an approved vaccine against both HAV and HBV
(Twinrix – Glaxo). Another formulation for infants (Pediarix – Glaxo)
contains vaccines against diphtheria, tetanus, pertussis (whooping
cough), polio and HBV.
• There are normally three vaccinations for children (birth, 1 and 6
months) or adults to provide protective immunity. The vaccine is
recommended for children up to 18 years and for adults at high risk.
31. Hepatitis D Virus
Now this virus belongs to
Togaviridae family,
genus Deltavirus
is defective RNA,
enveloped,
has same with HBV surface
Ag – HBsAg,
Modes of transmission:
•Percutanous exposures
– injecting drug use
•Permucosal exposures
– sex contact
32. Hepatitis D (HDV) or delta agent is a defective virus with
some similarities to plant viroids.
It cannot code for its own surface protein and thus in order to
produce more virus particles, it needs a helper virus;
this is HBV.
HDV is either acquired along with HBV (co-infection) or as
a super-infection of an already HBV-infected individual.
• Coinfection < 5%
- severe acute disease.
– low risk of chronic infection.
• Superinfection80%
– usually develop chronic HDV infection.
– high risk of severe chronic liver disease.
– may present as an acute hepatitis.
• Fulminant: 2 – 7.5%
33.
34.
35.
36. Hepatitis D - Prevention
• HBV-HDV Coinfection
– Pre or postexposure prophylaxis to prevent HBV
infection.
• HBV-HDV Superinfection
– Education to reduce risk behaviors among persons
with chronic HBV infection.
37. Hepatitis Е virus (HEV)
• is а small (32-34 nm in diameter),
nonenveloped single-stranded
+ ve RNA virus of the Calicivirus
family
• 13 variants are divided into three
groups.
• very labile and sensitive
• Can only be cultured recently
38. • Clinical Features
– The period of infectivity following acute infection has not been
determined but virus excretion in stools has been demonstrated up
to 14 days after illness onset.
– In most hepatitis E outbreaks, the highest rates of clinically evident
disease have been in young to middle-age adults
– No evidence of chronic infection has been detected in long-term
follow-up of patients with hepatitis E.
• Incubation period: Average 40 days, range 15-60 days
• Case-fatality rate: Overall, 1%-3%
Pregnant women, 15%-25%
• Illness severity is increased with age
• Chronic sequelae: None identified
39.
40. Hepatitis E -
Epidemiologic Features
• Most outbreaks associated with faecally contaminated drinking water.
• Several other large epidemics have occurred since in the Indian
subcontinent and the USSR, China, Africa and Mexico.
• In the United States and other nonendemic areas, where outbreaks of
hepatitis E have not been documented to occur, a low prevalence of
anti-HEV (<2%) has been found in healthy populations. The source of
infection for these persons is unknown.
• Minimal person-to-person transmission.
41.
42. Prevention
– Prevention of hepatitis E relies primarily on the provision of
clean water supplies.
– Prudent hygienic practices that may prevent hepatitis E and other
enterically transmitted diseases among travelers to developing
countries include avoiding:
• drinking water (and beverages with ice) of unknown purity
• uncooked shellfish
• uncooked fruits or vegetables that are not peeled or prepared
by the traveler
– No products are available to prevent hepatitis E.
43. Hepatitis C Virus - “non-A-non-B (NANB)
hepatitis.”
family Flaviviridae,
the genus Hepacivirus
6 genotypes of HCV are
known
44. Hepatitis C - Clinical Features
• Incubation period: Average 6-7 wks
Range 2-26 wks
• Clinical illness (jaundice): 30-40% (20-30%)
• Chronic hepatitis: 70%
• Persistent infection: 85-100%
• Immunity: No protective antibody
response identified
45. Chronic Hepatitis C Infection
• The spectrum of chronic hepatitis C infection is essentially the same
as chronic hepatitis B infection.
• All the manifestations of chronic hepatitis B infection may be seen,
albeit with a lower frequency i.e. chronic persistent hepatitis, chronic
active hepatitis, cirrhosis, and hepatocellular carcinoma.
• Risk Factors Associated with Transmission of HCV
- Transfusion or transplant from infected donor
- Injecting drug use
- Hemodialysis (yrs on treatment)
- Accidental injuries with needles/sharps
- Sexual/household exposure to anti-HCV-positive contact
- Multiple sex partners
- Birth to HCV-infected mother
46. Hypothetical model of the HCV replication cycle. Upon infection of the host cell
(large rectangle) the plus-strand RNA genome (RNA) is liberated into the cytoplasm
and translated. The polyprotein is processed and viral proteins remain tightly
associated with membranes of the ER. Minus-strand RNA (–RNA) is synthesized by
the replicase composed of NS3–5B and serves as template for production of excess
amounts of plus strand. Via interaction with the structural proteins plus-strand RNA
is encapsidated. Particles are enveloped by budding into the lumen of the ER and
virus particles are exported via transit through the Golgi complex.
51. 1. NIH Consensus Development Conference Statement; March 24-26, 1997.
2. Davis GL et al. Gastroenterol Clin North Am. 1994;23:603-613.
3. Koretz RL et al. Ann Intern Med. 1993;119:110-115.
4. Takahashi M et al. Am J Gastroenterol. 1993;88:240-243.
HCV infection
Chronic HCV Cirrhosis Hepatic Failure
Liver Cancer
Liver Transplant
Candidates
60-85%1
~20%4
~ 20%3
20%-50%2
HCV: Disease Progression
Time: 20-30 years
52. Identification and Planning
Common Schedule and Type of HCV
Testing
Identification and Planning Treatment
Diagnosis
• HCV Ab
• HCV RNA
Prognosis
• Liver biopsy
• Comorbidities
Treatment
Decision
• Genotyping
• Quant HCV
RNA
• IL28B genotype
Assess Response
and Resistance
• Quant HCV RNA
Decision to Treat Process
Stage
Assay
Genotypes: 1-6 associated with response to therapy:
G1: 65-75% SVR
G2/3: 70-80% SVR
53.
54. Hepatitis G
• is a newly discovered form of liver inflammation caused by hepatitis
G virus (HGV), a distant relative of the hepatitis C virus.
– HGV, also called hepatitis GB virus, was first described early in
1996.
– HGV is a positive-strand RNA virus belonging to the family
Flaviviridae.
– Little is known about the frequency of HGV infection, the nature
of the illness, or how to prevent it. What is known is that
transfused blood containing HGV has caused some cases of
hepatitis.
55. Clinical manifestation
– Some researchers believe that there may be a group of GB viruses,
rather than just one. Others remain doubtful that HGV actually
causes illness. If it does, the type of acute or chronic (long-lasting)
illness that results is not clear.
– Diagnosis is made by confirming the presence of HGV in the
blood by detecting HGV-RNA.
– When diagnosed, acute HGV infection has usually been mild and
brief.
– There is no evidence of serious complications, but it is possible
that, like other hepatitis viruses, HGV can cause severe liver
damage resulting in liver failure.
56. Transmission
–Transfused blood containing HGV has caused some cases of hepatitis.
For this reason, patients with hemophilia and other bleeding conditions
who require large amounts of blood or blood products are at risk of
hepatitis G.
•HGV has been identified in between 1-2% of blood donors in the
United States.
•Also at risk are:
–Patients with kidney disease who undergo hemodialysis
–Injection drug users
–It is possible that an infected mother can pass on the virus to her
newborn infant
–Sexual transmission also is a possibility
