Transcript Document

Hepatitis viruses. Features of
structure and main biological
properties
Vinnitsa National Pirogov Memorial
Medical University / Department of
microbiology


1.
2.
The term “viral hepatitis” refers to a
primary infection of the liver by any
one of a heterogeneous group of
“hepatitis viruses”. It consists of
types A, B, C, D, E, G.
Hepatitis viruses are taxonomically
unrelated (DNA and RNA viruses). The
features common to them are:
hepatotropism
ability to cause a similar icteric illness

1.
2.
3.

By epidemiological and clinical criteria,
two types of viral hepatitis had been
recognised for long:
A first type (this type was called infective or
infectious hepatitis)
Occurred sporadically or as epidemics;
Affecting mainly children and young
adults;
Transmitted by the fecal-oral route.
A second type (this type had been given
various names such as serum hepatitis or
transfusion hepatitis) transmitted mainly
by parenteral route
Type A virus hepatitis (HAV)


Belongs to the Picornaviridae family
Morphology.
1. HAV is a spherical ss(+)RNAincluding virus
2. 27-30 nm in diameter
3. Non enveloped
Classification of viral hepatitis
 Hepatitis
A virus
 Hepatitis B virus
 Hepatitis C virus
 Hepatitis D virus
 Hepatitis E virus
 Hepatitis G virus
HAV is transmitted by the fecal-oral
route
Pathogenesis
 The
clinical disease consists of two stages:
the prodromal (or preicteric) and the icteric
stage
Laboratory diagnosis
1.
2.
3.
IEM
Serology
Detection of viral antigens in stool
samples
Prophylaxis


1.
2.
General prophylaxis consists of:
Specific prophylaxis
Active
Passive
Treatment is symptomatic. No specific
antiviral drug is available
Type B hepatitis (HBV)
Antigen Structure
 HBsAg
 HBcAg
 HBeAg
 HBxAg
There are three important modes of
transmission of HBV infection:
parenteral, perinatal, sexual
Laboratory diagnosis
Detection of hepatitis B antigens and
antibodies (viral markers).
Prophylaxis


Prophylaxis includes:
General preventive measures
 Immunisation
1.
2.
Passive
Active.
Type C hepatitis (HCV)
 Hepatitis
C virus belongs to the family
Flaviviridae
 HCV is a 50-60 nm virus with a linear single
stranded RNA of positive polarity
(ss(+)RNA)
 Enclosed within a core and surrounded by
an envelope, carrying glycoprotein spikes
Laboratory diagnosis

It can be established by detection of anti-HCV by
ELISA.
 Viral genome (HCV RNA) detection
Type D (Delta) hepatitis (HDV)
 HDV
is a defective RNA virus depending on
the helper function of HBV for its replication
and expression. It belongs to genus
Deltavirus
Its mode of transmission is the
same as for HBV

1.
2.
Two types of infection are recognized
Coinfection
Superinfection
Laboratory diagnosis
 Delta
antigen
 Anti-delta antibodies