Viral hepatitis_RDP

VIRAL HEPATITIS
MRS.RISHITA D PATEL
PHARMACOLOGY
DEPARTMENT

VIRAL HEPATITIS
The term viral hepatitis is used to describe infection of the liver caused by
hepatotropic viruses.
Currently there are 5 main varieties of these viruses causing distinct types of viral
hepatitis:
Hepatitis A virus (HAV), causing a faecally-spread selflimiting disease.
Hepatitis B virus (HBV), causing a parenterally transmitted disease that may
become chronic.
 Hepatitis C virus (HCV), previously termed non-A, non-B (NANB) hepatitis virus
involved chiefly in transfusion-related hepatitis.
Hepatitis delta virus (HDV) which is sometimes associated as superinfection with
hepatitis B infection.
 Hepatitis E virus (HEV), causing water-borne infection.
While HBV is a DNA virus, all other human hepatitis viruses are RNA viruses
In addition to the nominal hepatitis viruses, other viruses that can also cause liver

CLINICAL TERMS
 Hepatitis: inflammation of liver;
 Acute Viral Hepatitis: symptoms last less than 6 months
 Acute Hepatic Failure: is the appearance of severe complications rapidly after
the first signs of liver disease (such as jaundice), and indicates that the liver
has sustained severe damage (loss of function of 80-90% of liver cells).Massive
hepatic necrosis with impaired consciousness within 8 weeks of onset of
illness.
Chronic Hepatitis: Inflammation of liver for at least 6 months
Cirrhosis: Replacement of liver tissue
fibrosis(scar tissue):These changes lead to loss of liver function.
Fulminant Hepatitis: severe impairment of hepatic functions or severe necrosis
of hepatocytes in the absence of preexisting liver disease.

Hepatitis A (formerly known as ―infectious hepatitis or epidemic jaundice)
is an acute infectious disease caused by Hepatitis A virus (HAV).
The disease is heralded by non-specific symptoms such as fever, chills,
headache, fatigue, generalized weakness and aches and pains, followed by
anorexia, nausea, vomiting, dark urine and jaundice.
The disease is benign with complete recovery in several weeks.

EPIDEMIOLOGICAL DETERMINANTS
Agent factors
a) AGENT: The causative agent, the hepatitis A virus, is an enterovirus of the
Picornaviridae family. It multiplies only in hepatocytes.
b) RESISTANCE: The virus is fairly resistant to heat and chemicals.
-Withstands heating to 600 C for 1 hr. and is not affected by chlorine in
doses usually employed for chlorination.
-Formalin is stated to be an effective disinfectant.
-The virus is inactivated by ultraviolet rays and by boiling for 5 minutes or
autoclaving.
RNA Naked RNA virus

c) RESERVOIR OF INFECTION: The human cases are the only reservoir of
infection.
d) PERIOD OF INFECTIVITY : The risk of transmitting HAV is greatest from 2
weeks before to 1 week after the onset of jaundice.
e) INFECTIVE MATERIAL : Mainly man’s faeces.
f) VIRUS EXCRETION: HAV is excreted in the faeces for about 2 weeks before
onset of jaundice and for up to 2 weeks thereafter.

Host factors
a) AGE: Infection with HAV is more frequent among children than in adults.
However, people from all ages may be infected if susceptible.
b) SEX: Both sexes are equally susceptible.
c) IMMUNITY: Immunity after attack probably lasts for life.
Environmental factors
Cases may occur throughout the year.
In India the disease tends to be associated with periods of heavy rainfall.

PATHOGENESIS
Hepatitis A virus is present in the liver and replicates there.
 It is present in the liver, bile, blood and stools in the pre-icteric incubation
period but viraemia and viral shedding in stool is diminished after jaundice
appears.
Evidence that hepatitis caused by HAV has an immunologic basis comes from
demonstration of following antibodies acting as serum markers for hepatitis A
infection
1. IgM anti-HAV antibody appears in the serum at the onset of symptoms of
acute hepatitis A.
 2. IgG anti-HAV antibody is detected in the serum after acute illness and
remains detectable indefinitely. It gives lifelong protective immunity against
reinfection with HAV.

Incubation period
10-50 days (usually 25 to 30 days).
Mode of Transmission
a) FAECAL-ORAL ROUTE: Major route of transmission. By contaminated water,
food or milk.
b) PARENTERAL ROUTE (Rarely): By blood and blood products or by skin
penetration through contaminated needles.
c) SEXUAL TRANSMISSION: May occur mainly among homosexual men because
of oral-anal contact.
Diagnosis
1. Demonstration of Virus in feces, blood, bile: By: Immunoelectron
microscopy
2. Virus Isolation
3. Detection of Antibody :By ELISA
4. Biochemical tests: I) Alanine aminotransferase (ALT) II) Bilirubin III) Protein

PREVENTION
hygienic measures and sanitation
passive immunization Human Immunoglobulin (Gamma globulin) given before
exposure to virus or early during the incubation period, will prevent or attenuate
a clinical illness.
active immunization Several inactivated or live attenuated vaccines against
hepatitis A have been developed.
Treatment:
nospecific, dietary food and long rest

Hepatitis B (serum hepatitis) caused by HBV infection has a longer
incubation period (30-180 days) and is transmitted parenterally such as
in recipients of blood and blood products, intravenous drug addicts,
patients treated by renal dialysis and hospital workers exposed to blood,
and by intimate physical contact such as from mother to child and by
sexual contact.
The disease may occur at any age.
HBV infection causes more severe form of illness that includes: acute
hepatitis B, chronic hepatitis, progression to cirrhosis, fulminant hepatitis
and an asymptomatic carrier stage.

HBV SHOW 3 FORMS OF VIRAL PARTICLES OF 2 SIZES: SMALL
(SPHERES
AND TUBULES/FILAMENTS) AND LARGE (SPHERES) AS UNDER:

i)Small particles are most numerous and exist in two forms— as 22 nm
spheres, and as tubules 22 nm in diameter and 100 nm long. These are
antigenically identical to envelope protein of HBV and represent excess of
viral envelope protein referred to as hepatitis B surface antigen (HBsAg).
ii) Large particles, 42 nm in diameter, are double-shelled spherical particles,
also called as Dane particles. These are about 100 to 1000 times less in
number in serum compared to small 22 nm particles and represent intact
virion of HBV.
Out of 3 morphology forms, only the Dane particle is considered infectious,
other circulating morphology forms are not infectious.

GENOMIC STRUCTURE OF
HEPATITIS B VIRUS

•S gene codes for the surface envelope protein, hepatitis B surface antigen
(HBsAg); this product is major protein.
•HBsAg is present on the outer surface of the large spherical particles as well
as in small spherical and tubular structures. Pre-S1 and pre-S2 regions of
genome are upstream of S gene and code for pre-S gene protein products
that includes receptor on the HBV surface and for hepatocyte membrane
proteins.
• The protein product of S-gene plus adjacent pre-S2 region is the middle
protein, while the protein products of pre-S1 plus pre-S2 regions is the
large protein.
•Large protein coming from both pre-S proteins is rich in complete virions.
•2. P gene is the largest and codes for DNA polymerase.
•3. C gene codes for two nucleocapsid proteins, HBeAg and a core protein
termed HBcAg.
•4. X gene codes for HBxAg which is a small non-particulate protein. HbxAg
has a role in transactivation the transcription of both viral and cellular
genes. Expression of HBxAg and its antibodies associated with enhanced

RESERVOIR OF INFECTION:
Men is the only reservoir of infection which can be spread either from carriers or from
cases.
 Infective material: -Contaminated blood is the main source, -Virus has been found in
body secretion such as saliva, vaginal secretion & Semen in infected material.
 Resistance: Readily destroyed by sodium hypochlorite, as is by heat sterilization in an
autoclave for 30-60 min.
Host factor
AGE:
Acute hepatitis B: 90% resolve by themselves; <1% develop fulminant hepatic failure. -
occurs in approx.:
Perinatal -1%
Childhood -10%(1-5 yr. age)
Late infection -30%(>5 yr. age)
Chronic hepatitis B: 2-10% progress to chronic state. -occur in approx.
Perinatal -95%
Childhood -80%
After 5 yr. of age -5-10%

High Risk Group:
People from endemic regions
Babies of mothers with chronic HBV
 Intravenous drug abusers
People with multiple sex partners
 Hemophiliacs and other patients requiting blood and blood product
treatments
 Health care personnel who have contact with blood
 Patients who are immunocompromised.

PATHOGENESIS
There is strong evidence linking immune pathogenesis with hepatocellular
damage:
i) Since a carrier state of hepatitis B without hepatocellular damage exists, it
means that HBV is not directly cytopathic.
ii) It has been observed that individuals with defect or deficiency of cellular
immunity have more persistent hepatitis B disease instead of clearing HBV
from their blood.
iii) In support of cell-mediated mechanism in hepatocellular damage by HBV
comes from observation that viral antigens (in particular nucleocapsid
proteins HbcAg and HbeAg) are attacked by host cytotoxic CD8+T
lymphocytes.
iv) The host response of CD8+T lymphocytes by elaboration of antiviral
cytokines is variable in different individuals and that determines whether
an HBV-infected person recovers, develops mild or severe disease, or
progresses to chronic disease.

MODE OF TRANSMISSION
Parenteral- IV drug abusers, health workers are at increased risk.
Sexual- sex workers and homosexuals are particular at risk.
 Perinatal (Vertical) – mother (HBeAg+) →infant. Mothers who are HBeAg
positive are much more likely to transmit to their offspring than those who
are not. Perinatal transmission is the main means of transmission in high
prevalence populations.

DIAGNOSIS
Serology
Liver Chemistry tests AST, ALT, ALP, and total Bilirubin
Histology- Immunoperoxidase staining
 HBV Viral DNA-Most accurate marker of viral DNA and detected by PCR
Liver Biopsy-to determine grade(Inflammation) and stage(Fibrosis) in
chronic Hepatitis

SEROLOGIC EVENTS
1) HBsAg :- It is the first marker to appear in blood after infection.
2) Anti-HBs(HBsAb) :Disappearance of HBsAg and the appearance of anti-HBs signals
recovery from HBV infection, non-infectivity.
3) Anti-HBc :- IgM anti-HBc appears shortly after HBsAg is detect (HBcAg alone dose
not appear in serum)
IgM-HBc may also or can persist for 3-6 months or longer.
IgG-HBc also appear during acute hepatitis B but persist indefinitely.
4) HBeAg : HBeAg appear in blood concurrently with HBsAg, or soon afterwards.
HBeAg is a soluble protein found only in HBeAg positive serum.
HBeAg indicate viral replication and infectivity.
Persistence of HBeAg in serum beyond 3 month indicate an increased like hood of
chronic hepatitis B.

Prevention
 Vaccination - highly effective recombinant vaccines
 Hepatitis B Immunoglobulin (HBIG) -exposed within 48 hours of the
incident/neonates whose mothers are HBsAg and HBeAg positive.
Other measures -screening of blood donors, blood and body fluid
precautions.

The diagnosis of this major category of hepatitis was earlier made after
exclusion of infection with other known hepatitis viruses in those times and
was initially designated non-A, non-B (NANB) hepatitis.
 However, now it has been characterised and is called hepatitis C.
Hepatitis C infection is acquired by blood transfusions, blood products,
haemodialysis, parenteral drug abuse and accidental cuts and needle-pricks
in health workers.
 About 90% of post-transfusion hepatitis is of hepatitis C type. About 1-2%
of volunteer blood donors and up to 5% of professional blood donors are
carriers of HCV.
Hepatitis C has an incubation period of 20-90 days (mean 50 days).
Clinically, acute HCV hepatitis is milder than HBV hepatitis but HCV has a
higher rate of progression to chronic hepatitis than HBV.
Persistence of infection and chronic hepatitis are the key features of HCV.
Occurrence of cirrhosis after 5 to 10 years and progression to hepatocellular
carcinoma are other late consequences of HCV infection.
Currently, HCV is considered more important cause of chronic liver disease
worldwide than HBV.

HEPATITIS C VIRUS (HCV)
HCV is a single-stranded,
enveloped RNA virus, having
a diameter of 30-60 nm.
HCV genome has about
3000 amino acids.
The genomic organisation
of HCV shows a 5’ terminal
end, C (capsid) region and
the envelope regions E1 and
E2 in the exons.
The half life of the virus
particles in the serum is
around 3 hours and may be
as short as 45 minutes.
 In addition to replicating in
the liver the virus can
multiply in lymphocytes.

INCUBATION PERIOD : 40-120 DAYS
Mode of Transmission :
Intravenous Drug Use
Healthcare Exposure: Blood Transfusion, transfusion of Blood products,
Organ Transplant without HCV screening carry significant risk of
infection.
Hemodialysis
Accidental injuries with needles/sharps
 Sexual/household exposure to anti-HCV-positive contact
 Multiple sex partners
 Vertical Transmission: Vertical transmission of hepatitis C from an
infected mother to her child

DIAGNOSI
S
•HCV antibody –
ELISA used to diagnose hepatitis C infection.
Not useful in the acute phase as it takes at least 4 weeks after infection
before antibody appears.
• HCV-RNA - various techniques are available e.g. PCR and branched
DNA.
May be used to diagnose HCV infection in the acute phase. However, its
main use is in monitoring the response to antiviral therapy.
•HCV-antigen - an EIA (enzyme immunoassay) for HCV antigen is
available. It is used in the same capacity as HCV-RNA tests but is much

PREVENTION
 Only General Prophylaxis, such as blood, tissue, organ
screening, is possible.
No specific active or passive immunizing agent is available.
Treatment
Interferon - may be considered for patients with chronic active
hepatitis.
The response rate is around 50% but 50% of responders will
relapse upon withdrawal of treatment. Ribavirin - there is less
experience with ribavirin than interferon. However, recent
studies suggest that a combination of interferon and ribavirin is

HEPATITIS D
Hepatitis D, also referred to as hepatitis D virus (HDV) and
classified as Hepatitis delta virus, is a disease caused by a small
circular enveloped RNA virus.
 HDV is considered to be a subviral satellite because it can
propagate only in the presence of the hepatitis B virus (HBV).
Hepatitis D virus VIRION:
spherical, 36-38 nm particle with an outer coat composed of the
HBsAg surrounding ssRNA genome.
Satellite virus : replicates only in the presence of HBV

Incubation Period
2-12 weeks
Mode of Transmission
The primary route of Transmission are believed to be similar to those
of HBV, though HDV does not appear to be sexually transmitted
disease.
Clinical Features
Infection is dependent on HBV replication, as HBV provides an HBsAg
envelop for HDV.
 Two types of infection are recognisesd, coinfection and
superinfection.
In Coinfection, delta and HBV are transmitted together at the same
time.
In Superinfection, delta infection occurs in a person already carrier of

DIAGNOSIS
 Delta antigen is primarily expressed in liver cell nuclei,
where it can be demonstrated by immunofluorescence.
 Anti-delta antibodies appear in serum and can be
identified by ELISA.
IgM antibody appears 2-3 weeks after infection and is soon
replaced by the IgG antibody in acute delta infection.

HDV RNA is detectable in the blood and liver just before
and in the early days of acute symptomatic disease.
IgM anti-HDV antibody is the most reliable indicator of
recent HDV exposure, although its appearance is late and
frequently short-lived.
Nevertheless, acute co-infection by HDV and HBV is best
indicated by detection of IgM against both HDAg and
HBcAg (denoting new infection with hepatitis B).
With chronic delta hepatitis arising from HDV
superinfection, HBsAg is present in serum, and anti-HDV
antibodies (IgG and IgM) persist for months or longer.
Vaccination for HBV also prevents HDV infection.

PREVENTION
HBV-HDV Coinfection
Pre or post exposure prophylaxis to prevent HBV infection.
Screening of blood donor for HBsAg.
 HBV-HDV Superinfection
Education to reduce risk behaviors among persons with
chronic HBV infection.

HEPATITIS E
 Hepatitis E is a viral hepatitis (liver inflammation) caused by
infection with a virus called hepatitis E virus (HEV).
 Although Hepatitis E often causes an acute and self-limiting
infection (in that it usually goes away by itself and the patient
recovers) with low mortality rates.
 It bears a high risk of developing chronic hepatitis in
immunocompromised patients with substantial mortality rates.
Hepatitis E occasionally develops into an acute, severe liver
disease, and is fatal in about 2% of all cases.
 In pregnant women the disease is more often severe and is
associated with a clinical syndrome called fulminant hepatic
failure.

HEPATITIS E VIRUS
HEV is spherical nonenveloped virus, 29-nm to 32 nm in
diameter, with a ssRNA genome.
 The surface of the virion shows indentation and spikes.
 The Virus is very labile.
 has been classified in the genus Herpes virus under the
family Caliciviridae.
Incubation Period : 2-9 weeks
Animal Reservoir: Pigs

SIGNS AND SYMPTOMS
Acute Infections:
•The incubation period of hepatitis E varies from 3 to 8 weeks.
After a short prodromal phase symptoms lasting from days to weeks follow.
1. They may include jaundice, fatigue and nausea.
2. Viral RNA becomes detectable in stool and blood serum during
incubation period.
3. Serum IgM and IgG antibodies against HEV appear just before onset of
clinical symptoms.
4. Recovery leads to virus clearance from the blood, while the virus may
persist in stool for much longer.
5. Recovery is also marked by disappearance of IgM antibodies and increase
of levels of IgG antibodies.

Chronic Infections:
While usually an acute disease, in
immunocompromised subjects, particularly in solid
organ transplanted patients, hepatitis E may cause a
chronic infection.
Occasionally this may cause liver fibrosis and
cirrhosis.

MODE OF TRANSMISSION
It is spread mainly by the fecal-oral route due to
fecal contamination of water supplies or food;
person-to-person transmission is uncommon.

DIAGNOSIS
ELISA kits are available for IgG and IgM antibodies,
using recombinant and synthetic peptide antigens.
Prevention Sanitation: Avoid drinking water of
unknown purity, uncooked shellfish, and uncooked
fruit/vegetables not peeled or prepared by traveller.

HEPATITIS G
 GB virus C (GBV-C), formerly known as hepatitis G virus
(HGV) and also known as HPgV is a virus in the Flaviviridae
family and a member of the Pegivirus genus, is known to
infect humans, but is not known to cause human disease.
 HGV RNA has been found in patients with acute, chronic
and fulminant hepatitis, patients with multiple transfusions
and hemodialysis, intravenous drug addicts and blood
donors.

Viral hepatitis_RDP

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